ch16: life cycle nutrition: infancy, childhood, and adolescence
infant formula
After a year of breastfeeding, a nursing mother can wean her baby directly to cow's milk if she chooses, but if she wants to provide a substitute for breast milk within the first year, she must select an appropriate infant formula and learn to prepare it. Cow's milk is inappropriate during the first year of life. Infant Formula Composition Formula manufacturers copy the nutrient composition of breast milk as closely as possible. Figure 16-4 illustrates the energy-nutrient balance of breast milk, infant formula, and cow's milk. All formula-fed infants should be given iron-fortified infant formulas. Use of iron-fortified formulas has increased over the past few decades and accounts for the decline in iron-deficiency anemia observed among infants in the United States.
hyperactivity and hyper behavior
All children are naturally active, and many of them become overly active on occasion—for example, in anticipation of a birthday party. Such behavior is markedly different from true hyperactivity. Hyperactivity Children who are hyperactive have trouble sleeping, cannot sit still for more than a few minutes at a time, act impulsively, and have difficulty paying attention. These behaviors interfere with social development and academic progress. The causes of hyperactivity remain unknown, but the condition affects about 9 percent of young school-age children. To resolve the problems surrounding hyperactivity, physicians often recommend specific behavioral strategies, special educational programs, and psychological counseling. If these interventions are ineffective, they may prescribe medication. Research on hyperactivity has focused on several nutritional factors as possible causes or treatments. Parents often blame sugar. They hopefully believe that simply eliminating candy and other sweet treats will solve the problem. Studies have found no convincing evidence that sugar causes or worsens hyperactivity but dietary changes may still be helpful. Sugar-sweetened foods and beverages displace more nutritious choices from the diet, and, as stated previously, nutrient deficiencies may cause behavioral problems. Food additives have also been blamed for hyperactivity and other behavior problems in children, but scientific evidence to substantiate the connection has been elusive. Limited research suggests that food additives such as artificial colors or sodium benzoate preservative (or both) may exacerbate hyperactive symptoms such as inattention and impulsivity in some children. Additional studies are needed to evaluate the findings and to determine which, if any, additives may be responsible for specific negative behaviors. Misbehaving Even a child who is not truly hyperactive can be difficult to manage at times. Michael may act unruly out of a desire for attention, Jessica may be cranky because of a lack of sleep, Christopher may react violently after watching too much television, and Ashley may be unable to sit still in class because she lacks time to exercise. All of these children may benefit from more consistent care—regular hours of sleep, regular mealtimes, and regular outdoor activity.
special needs of preterm infants
An estimated one out of ten pregnancies in the United States results in a preterm birth. The terms preterm and premature signify that there is incomplete fetal development, or immaturity, of many body systems. As might be expected, preterm birth is a leading cause of infant deaths. Preterm infants face physical independence from their mothers before some of their organs and body tissues are ready. The rate of weight gain in the fetus is greater during the last trimester of gestation than at any other time. A preterm infant, who misses out on this crucial developmental time, is most often a low-birthweight infant as well. A premature birth deprives the infant of the nutritional support of the placenta during the time of maximal growth. The last trimester of gestation is also a time of building nutrient stores. Being born with limited nutrient stores intensifies the already precarious situation for the infant. The physical and metabolic immaturity of preterm infants further compromises their nutrition status. Nutrient absorption from an immature GI tract is limited, and preterm, low-birthweight infants commonly experience deficiencies of the fat-soluble vitamins, and the minerals calcium, iron, and zinc. Preterm breast milk is well suited to meet a preterm infant's needs. During early lactation, preterm breast milk contains higher concentrations of protein and is lower in volume than term breast milk. The low milk volume is advantageous because preterm infants consume small quantities of milk per feeding, and the higher protein concentration allows for better growth. In many instances, supplements of nutrients specifically designed for preterm infants are added to the mother's expressed breast milk and fed to the infant from a bottle. When fortified with a preterm supplement, preterm breast milk supports growth at a rate that approximates the growth rate that would have occurred within the uterus.
energy nutrients in breast milk
Carbohydrate The main carbohydrate in breast milk (and standard infant formula) is the disaccharide lactose. In addition to being easily digested, lactose enhances calcium absorption. The carbohydrate component of breast milk also contains abundant oligosaccharides, which are present only in trace amounts in cow's milk and infant formula made from cow's milk. Breast milk oligosaccharides help protect the infant from infection by preventing the binding of pathogens to the infant's intestinal cells. Fat and Fatty Acids As for the lipids, breast milk contains a generous proportion of the essential fatty acids linoleic acid and linolenic acid, as well as their longer-chain derivatives arachidonic acid and DHA. DHA accumulation in the brain is higher in breastfed infants than in formula-fed infants. Research has focused on the mental and visual development of breastfed infants and infants fed standard formula with and without DHA added. Results of these studies are mixed, perhaps because of slight differences in experimental design. Adding DHA to standard infant formulas has no adverse effects, and most standard formulas are currently fortified with both DHA and arachidonic acid. Protein The amount of protein in breast milk is less than in cow's milk, but this quantity is actually beneficial because it places less stress on the infant's immature kidneys to excrete urea, the major end product of protein metabolism. Much of the protein in breast milk is alpha-lactalbumin, which is efficiently digested and absorbed. Vitamins With the exception of vitamin D, the vitamins in breast milk are ample to support infant growth. The vitamin D in breast milk is low, however, and vitamin D deficiency impairs bone mineralization. Vitamin D deficiency is most likely in infants who are not exposed to sunlight daily, have darkly pigmented skin, and receive breast milk without vitamin D supplementation. Reports of infants in the United States developing the vitamin D-deficiency disease rickets and recommendations to limit sun exposure in infants younger than 6 months of age prompted revisions in vitamin D guidelines. The American Academy of Pediatrics recommends a vitamin D supplement for all infants who are breastfed exclusively and for all infants who do not receive at least 1 liter (1000 milliliters, roughly 1 quart, or 32 ounces) of vitamin D-fortified formula daily. Minerals The calcium content of breast milk is ideal for infant bone growth, and the calcium is well absorbed. Breast milk contains relatively small amounts of iron, but the iron has high bioavailability. Zinc also has high bioavailability, thanks to the presence of a zinc-binding protein. Breast milk is low in sodium, another benefit for the infant's immature kidneys. Fluoride promotes the development of strong teeth, but breast milk is not a good source. Supplements Many pediatricians routinely prescribe liquid supplements containing vitamin D, iron, and fluoride as outlined in Table 16-2. In addition, infants receive a single dose of vitamin K at birth to protect them from bleeding to death. (See Chapter 11 for a description of vitamin K's role in blood clotting.)
nutrition during adolescence
As children pass through adolescence on their way to becoming adults, they experience distinctive, crucial, developmental changes. Their physical changes make their nutrient needs high, and their emotional, intellectual, and social changes make meeting those needs a challenge. Teenagers make many more choices for themselves than they did as children. They are not fed, they eat. Food choices made during the teen years profoundly affect present and future health. At the same time, social pressures thrust choices at them, such as whether to drink alcoholic beverages and whether to develop their bodies to meet extreme ideals of slimness or athletic prowess. Their interest in nutrition—both valid information and misinformation—derives from personal, immediate experiences. They are concerned with how their dietary choices can improve their lives now—they engage in fad dieting in order to fit into a new bathing suit, avoid greasy foods in an effort to clear acne, or eat a plate of spaghetti to prepare for a big sporting event. In presenting information on the nutrition and health of adolescents, this section includes many topics of interest to teens.
energy intake and activity in childhood
As mentioned, children's energy needs vary widely, depending on their growth and physical activity. A 1-year-old child needs about 800 kcalories a day; an active 6-year-old child needs twice as many kcalories a day. By age 10, an active child needs about 2000 kcalories a day. Total energy needs increase slightly with age, but energy needs per kilogram of body weight actually decline gradually. Physically active children of any age need more energy because they expend more, and inactive children can develop obesity even when they eat less food than the average. Unfortunately, our nation's children are becoming less and less active; child care programs and schools would serve our children well by offering more activities to promote physical fitness. Children who learn to enjoy physical play and exercise, both at home and at school, are best prepared to maintain active lifestyles as adults. Some children, notably those adhering to vegan diets, may have difficulty meeting their energy needs. Grains, vegetables, and fruits provide plenty of fiber, adding bulk, but may provide too little energy to support growth. Soy products, other legumes, and nut or seed butters offer more concentrated sources of energy to support optimal growth and development.
frequency and duration of breastfeeding
Breast milk is more easily and completely digested than formula, so breastfed infants usually need to eat more frequently than formula-fed infants do. During the first few weeks, approximately 8 to 12 feedings a day—on demand, as soon as the infant shows early signs of hunger such as increased alertness, activity, or suckling motions—promotes optimal milk production and infant growth. Crying is a late indicator of hunger. An infant who nurses every 2 to 3 hours and sleeps contentedly between feedings is adequately nourished. As the infant gets older, stomach capacity enlarges and the mother's milk production increases, allowing for longer intervals between feedings. Even though infants obtain about half the milk from the breast during the first 2 to 3 minutes of suckling, they should be encouraged to breastfeed on the first breast for as long as they are actively suckling, before being offered the second breast. The next feeding begins on the breast offered last. The infant's suckling, as well as the complete removal of milk from the breast, stimulates milk production. Energy Nutrients The energy-nutrient composition of breast milk differs dramatically from that recommended for adult diets (see Figure 16-3). Yet for infants, breast milk is nature's most nearly perfect food, providing the clear lesson that people at different stages of life have different nutrient needs.
carbs and fiber in childhood
Carbohydrate recommendations are based on the brain's glucose needs. After 1 year of age, the brain's use of glucose remains fairly constant and is within the adult range. Carbohydrate recommendations for children older than 1 year are therefore the same as for adults (see the inside front cover). Fiber recommendations derive from adult intakes shown to reduce the risk of heart disease and are based on energy intakes. Consequently, fiber recommendations for younger children with low energy intakes are less than those for older ones with high energy intakes (see the inside front cover).
mealtimes at home
Child's influence over family food decisions -Teaching consumer skills Children's preferences -Make mealtimes fun Learning through participation -Help plan and prepare meals avoid power struggles -how much and whether to eat the food choking prevention -adult should be present when child is eating playing first -More attentive during meal times snacking -limit access to concentrated sweets --preference for sweets is innate --healthy snack ideas Table 16-13, page 510 preventing dental caries -behaviors to encourage --brush and floss after meals --brush or rinse after eating snacks --avoid sticky foods --select crisp or fibrous food frequently be a role model
malnutrition-lead connection
Children who are malnourished are vulnerable to lead poisoning. They absorb more lead if their stomachs are empty; if they have low intakes of calcium, zinc, vitamin C, or vitamin D; and, of greatest concern because it is so common, if they are iron deficient. In a vicious cycle, iron deficiency weakens the body's defenses against lead absorption, and lead poisoning can cause iron deficiency. Common to both iron deficiency and lead poisoning are a low socioeconomic background and a lack of immunizations against infectious diseases. Another common factor is pica—a craving for nonfood items. Many children with lead poisoning eat dirt or chips of old paint, two common sources of lead The anemia brought on by lead poisoning may be mistaken for a simple iron deficiency and therefore may be incorrectly treated. Like iron deficiency, mild lead toxicity has nonspecific symptoms, including diarrhea, irritability, and fatigue. Adding iron to the diet does not reverse the symptoms; exposure to lead must stop and treatment for lead poisoning must begin. With further exposure, the symptoms become more pronounced, and children develop learning disabilities and behavioral problems. Still more severe lead toxicity can cause irreversible nerve damage, paralysis, and death. Approximately half a million children between the ages of 1 and 5 in the United States have blood lead concentrations above 5 micrograms per deciliter, the level at which the Centers for Disease Control and Prevention recommend that public health actions be launched. Sometimes lead toxicity in young children comes from their own behaviors and activities—putting their hands in their mouths, playing in dirt and dust, or chewing on nonfood items such as crayons. Unfortunately, the body readily absorbs lead during times of rapid growth and hoards it possessively thereafter. Lead is not easily excreted and accumulates mainly in the bones, but also in the brain, teeth, and kidneys. Tragically, a child's neuromuscular system is also maturing during these first few years of life. No wonder children with elevated lead levels experience impairment of balance, motor development, and the relaying of nerve messages to and from the brain. Deficits in intellectual development are only partially reversed when blood lead levels decline. Federal laws mandating reductions in leaded gasoline, lead-based solder, and other products over the past several decades have helped reduce the amounts of lead in food and in the environment in the United States. As a consequence, the prevalence of lead toxicity in children has declined dramatically for most of the country, but lead exposure is still a threat in certain communities. Table 16-8 presents strategies for defending children against lead toxicity. Unfortunately, regulations and precautions to protect people from lead contamination sometimes fail. In Flint, Michigan, dangerous levels of lead and other toxins in the water supply occurred when the city switched water sources to cut costs. Residents of Flint, including many children, were exposed to the health risks posed by lead-contaminated water.
energy and nutrient needs
Children's appetites begin to diminish around 1 year, consistent with their slowing growth. Thereafter, children spontaneously vary their food intakes to coincide with their growth patterns; they demand more food during periods of rapid growth than during slow growth. Sometimes they seem insatiable, and at other times they seem to live on air and water. Children's energy intakes also vary widely from meal to meal. Even so, their total daily intakes remain remarkably constant. If children eat less at one meal, they typically eat more at another. Children who are overweight do not always adjust their energy intakes appropriately, however, and may eat in response to external cues such as television commercials, disregarding hunger and satiety signals.
choice of complementary foods
Complementary foods should provide variety, balance, and moderation. Commercial baby foods offer a variety of palatable, nutritious foods in a safe and convenient form. Caregivers should not feed directly from the jar; instead, spoon the needed portion into a dish and feed from there, leaving the leftovers in the jar uncontaminated by a used spoon. Homemade infant foods can be as nutritious as commercially prepared ones, so long as the cook uses fresh, whole foods without added salt, sugar, or seasonings. Pureed food can be frozen in ice cube trays, providing convenient-size blocks of food that can be thawed, warmed, and fed to the infant. To guard against foodborne illnesses, hands and equipment must be kept clean. Nutrients of Concern With respect to nutrient needs, the nutrients needed earliest are iron, zinc, and vitamin C. Rapid growth demands iron. At about 4 to 6 months of age, the infant begins to need more iron than body stores plus breast milk or iron-fortified formula can provide. In addition to breast milk or formula, infants can get iron from iron-fortified cereals, and once they readily accept complementary foods, meats and legumes can also provide iron (see Photo 16-4). Note that food labels provide insufficient information about the iron in foods. Iron-fortified cereals might be expected to contribute a significant amount of iron to an infant's diet, but the iron's bioavailability is poor. Caregivers can enhance iron absorption from iron-fortified cereals by serving vitamin C-rich foods with meals. The concentration of zinc in breast milk is high initially, but decreases sharply over the first few months of lactation. The high efficiency of an infant's zinc absorption does not compensate for its low concentration over time. Infant formulas are fortified with zinc at levels higher than those found in breast milk. Thus, breastfed infants depend more on complementary foods to provide adequate zinc intakes than formula-fed infants do. Infant cereals are not routinely fortified with zinc, so the best sources are protein foods such as meats, poultry, seafood, eggs, and (to a lesser extent) legumes. (Zinc is not as well absorbed from legumes as it is from other protein foods.) The best sources of vitamin C are fruits and vegetables (see Chapter 10, Vitamin C Food Sources). It has been suggested that infants who are introduced to fruits before vegetables may develop a preference for sweets and find the vegetables less palatable, but no evidence supports this notion. Fruit juice is a good source of vitamin C, but excessive juice intake can lead to diarrhea in infants and young children. Furthermore, too much fruit juice contributes excessive kcalories and displaces other nutrient-rich foods. The American Academy of Pediatrics recommends feeding no fruit juice in the first year and limiting juice for children 1 to 3 years old to 4 ounces per day. For the sake of a child's dental health, fruit juices should be served in cups, not in bottles.
nutrition during childhood
Each year from age 1 to adolescence, a child typically grows taller by 2 to 3 inches and heavier by 5 to 6 pounds. Growth charts provide valuable clues to a child's health. Weight gains out of proportion to height gains may reflect overeating and inactivity, whereas measures significantly less than the standard suggest inadequate nutrition. Increases in height and weight are only two of the many changes growing children exhibit (see Figure 16-7). At age 1, children can stand alone and are beginning to toddle; by 2, they can walk and are learning to run; and by 3, they can jump and climb with confidence. Bones and muscles increase in mass and density to make these accomplishments possible. Thereafter, lengthening of the long bones and increases in musculature proceed unevenly and more slowly until adolescence.
how to introduce complementary foods
Early feeding strategies are critical in establishing healthy food preferences and habits that last throughout life. Infants (and toddlers) learn from their caregivers what, when, and how to eat. Caregivers must therefore understand how infants signal hunger and satiety (see Table 16-4) and how to respond appropriately—a process known as responsive feeding. By clearly and consistently responding to a child's needs at mealtimes, the child learns to identify internal hunger, thirst, and satiety signals; to ask for foods or beverages when hungry or thirsty; and to stop eating when full. One approach for introducing foods, called baby-led weaning, offers graspable, soft finger foods instead of spoon-feeding pureed foods. Baby-led weaning promotes hand-eye coordination, self-regulation, and independence. Many parents use a combination of spoon feeding and baby-led weaning, depending on the infant's acceptance.
energy intake and activity in infants
Energy Intake and Activity A healthy infant's birthweight doubles by about 5 months of age and triples by 1 year, typically reaching 20 to 25 pounds. The infant's length changes more slowly than the weight, increasing by about 10 inches from birth to 1 year. By the end of the first year, infant growth slows considerably, and during the second year, an infant typically gains less than 10 pounds and grows about 5 inches in length. By the age of 2, healthy children have attained approximately half of their adult height. Not only do infants grow rapidly, but their energy requirements are remarkably high—about twice those of adults, based on body weight. A newborn baby requires about 450 kcalories per day, whereas most adults require about 2000 kcalories per day. Expressed in terms of body weight, this difference is remarkable. Infants require about 100 kcalories per kilogram of body weight per day, whereas most adults need fewer than 40 (see Table 16-1). If an infant's energy needs were applied to an adult, a 170-pound adult would require more than 7000 kcalories a day. After 6 months, the infant's energy needs decline as the growth rate slows, but some of the energy saved by slower growth is spent in increased activity
energy and nutrient needs in adolescence
Energy and nutrient needs are greater during adolescence than at any other time of life (see Photo 16-14), except pregnancy and lactation. In general, nutrient needs rise throughout childhood, peak in adolescence, and then level off or even diminish as the teen becomes an adult.
food allergy and intolerance
Food allergy is frequently blamed for physical and behavioral abnormalities in children, but only about 8 percent of children younger than 4 years of age are diagnosed with true food allergies. Food allergies diminish with age, until in adulthood they affect less than 4 percent of the population. The prevalence of food allergy, especially peanut allergy, is on the rise, however. Reasons for an increase in peanut allergy are not yet clear, but possible contributing factors include genetics, composition and diversity of GI microbiota during infancy, food preparation methods (roasting peanuts at very high temperatures makes them more allergenic), and exposure to medicinal skin creams containing peanut oil. A true food allergy occurs when fractions of a food protein or other large molecule are absorbed into the blood and elicit an immunologic response. (Recall that proteins are normally dismantled in the digestive tract to amino acids that are absorbed without such a reaction.) The body's immune system reacts to these large food molecules as it does to other antigens—by producing antibodies, histamines, and other defensive agents. Detecting Food Allergy Allergies may have one or two components. They always involve antibodies, but they may or may not involve symptoms. Therefore, allergies cannot be diagnosed from symptoms alone. Even symptoms exactly like those of an allergy may not be caused by an allergy. Food allergy should be considered when an individual, especially a young child, experiences symptoms such as skin rash, respiratory difficulties, vomiting, diarrhea, or anaphylactic shock (described later) within minutes to hours after eating. Diagnosis of food allergy requires medical testing and food challenges. Once a food allergy has been diagnosed, the required treatment is strict elimination of the offending food. Children with allergies, like all children, need all their nutrients, so it is important to include other foods that offer the same nutrients as the eliminated foods. Nutrition counseling and growth monitoring are recommended for all children with food allergies. Allergic reactions to food may be immediate or delayed. In either case, the antigen interacts immediately with the immune system, but the timing of symptoms varies from a few minutes to 24 hours after consumption of the antigen. Identifying the food that causes an immediate allergic reaction is fairly easy because the time interval from ingestion to symptoms is short. Identifying the food that causes a delayed reaction is more difficult because the symptoms may not appear until much later. By this time, many other foods may have been eaten, complicating the picture. Anaphylactic Shock The life-threatening food allergy reaction of anaphylactic shock is most often caused by shellfish, peanuts, wheat, milk, fish, tree nuts, soy, and eggs (see Photo 16-8). Among these foods, peanuts, milk, soy, and eggs most often cause problems in children. Children are more likely to outgrow allergies to milk, soy, and eggs than allergies to peanuts. Peanuts cause more life-threatening reactions than do all other food allergies combined. Research is currently under way to help people with peanut allergies to tolerate small doses, thus saving lives and minimizing reactions. Families of children with a life-threatening food allergy and the school personnel who supervise those children must guard them against any exposure to the allergen. The child must learn to identify which foods pose a problem and then learn and practice refusal skills for all foods that may contain the allergen. Parents of children with allergies can pack safe lunches and snacks and ask school officials to strictly enforce a "no swapping" policy in the lunchroom. The child and caregivers must be able to recognize symptoms of impending anaphylactic shock: Tingling sensation in the mouth Swelling of the tongue and throat Irritated, reddened eyes Difficulty breathing, asthma Hives, swelling, rashes Vomiting, abdominal cramps, diarrhea Drop in blood pressure Loss of consciousness Any person with food allergies severe enough to cause anaphylactic shock should wear a medical alert bracelet or necklace. Finally, the child and the school staff should be prepared with injections of epinephrine, which prevents anaphylactic shock after exposure to the allergen by opening the airways and maintaining the heartbeat and blood pressure. Many preventable deaths occur each year when people with food allergies accidentally ingest the allergen but have no epinephrine available. Food Labeling As Chapter 2 describes, food labels must list the presence of common allergens in plain language. For example, a food containing "textured vegetable protein" must say "soy" on its label. People with food allergies rely heavily on the accuracy of food labels. The FDA is considering adding sesame to its list of major food allergens that require label disclosure as allergy to sesame has increased significantly over the past two decades. Technology may soon offer new solutions. New drugs are being developed that may interfere with the immune response that causes allergic reactions. Also, through genetic engineering, scientists may one day create allergen-free peanuts, soybeans, and other foods to make them safer. Food Intolerances Not all adverse reactions to foods are food allergies, although even physicians may describe them as such. Signs of adverse reactions to foods include stomachaches, headaches, rapid pulse rate, nausea, wheezing, hives, bronchial irritation, coughs, and other such discomforts. Among the causes may be reactions to chemicals in foods, such as the flavor enhancer monosodium glutamate (MSG), the natural laxative in prunes, or the mineral sulfur; digestive diseases, obstructions, or injuries; enzyme deficiencies such as lactose intolerance; and even psychological aversions. These reactions involve symptoms but no antibody production. Therefore, they are food intolerances, not allergies. Pesticides on produce may also cause adverse reactions. Pesticides that were applied in the fields may linger on foods. Health risks from pesticide exposure may be low for healthy adults, but children are vulnerable. Therefore, government agencies have set a tolerance level for each pesticide by first identifying foods that children commonly eat in large amounts and then considering the effects of pesticide exposure during each stage of development. Chapter 19 revisits the issues surrounding the use of pesticides on food crops. Hunger, lead poisoning, hyperactivity, and allergic reactions can all adversely affect a child's nutrition status and health. Fortunately, each of these problems has solutions. They may not be easy solutions, but programs are in place and improvements are evident. As for the most pervasive health problem for children in the United States today—obesity—health experts and researchers understand much about the causes, the consequences, and even the solutions, but putting this knowledge into actions that produce success is an ongoing challenge.
foods to omit
Foods and beverages with added sugars, including baby food "desserts," deserve no place in the diets of infants and toddlers during the first two years of life. They convey no nutrients to support growth, and the surplus food energy they deliver can lead to obesity. Products containing sugar alcohols such as sorbitol should also be limited because they may cause diarrhea. Canned vegetables are also inappropriate for infants because they often contain too much sodium. Honey and corn syrup should never be fed to infants because of the risk of botulism. Infants and even young children cannot safely chew and swallow any of the foods listed in Table 16-5; they can easily choke on these foods, a risk not worth taking. Nonfood items may present even greater choking hazards. Parents and caregivers must conscientiously eliminate choking hazards from children's environments.
foods at one year
Ideally, a 1-year-old will sit at the table, eat many of the same foods everyone else eats, and drink liquids from a cup, not a bottle. Whole cow's milk (2 to 3 cups a day) can become a major source of many of the nutrients the infant needs. More milk than this can displace iron-rich foods and can lead to milk anemia. If powdered milk is used, it should contain some fat. Despite some infant formula brands' aggressive marketing of "toddler milks," (sugar-sweetened milk-based drinks for toddlers) and misconceptions about their benefits, these drinks are not recommended for toddler consumption. In fact, pediatric experts specifically recommend against feeding toddler milks to young children because children do not need them and the drinks contain added sugars. Other foods—meats, other protein foods, iron-fortified cereals, enriched or whole-grain breads, fruits, and vegetables—should be supplied in variety and in amounts sufficient to round out total energy needs
psychological development in childhood obesity
In addition to the physical penalties, childhood obesity imposes a host of emotional and social problems on children. Because people frequently judge others on appearance more than on character, children who are overweight or obese are often victims of prejudice and bullying. Many suffer discrimination by adults and rejection by their peers. They may have poor self-images, a sense of failure, and a passive approach to life. Television shows, which exert a major influence in children's lives, often portray the person who is overweight as the bumbling misfit. Children who are overweight may come to accept this negative stereotype in themselves and in others, which can lead to additional emotional and social problems. Researchers investigating children's reactions to various body types find that both children who are healthy weight and those who are underweight respond unfavorably to overweight bodies.
breast milk
In the United States, the two dietary practices that exert the most significant effect on an infant's nutrition are the milk the infant receives and the age at which complementary foods are introduced. A later section discusses the introduction of complementary foods, but as to the milk, the American Academy of Pediatrics strongly recommends breastfeeding for healthy full-term infants, except where specific contraindications exist. The Academy of Nutrition and Dietetics also advocates breastfeeding for the nutritional health of the infant as well as for the many other benefits it provides both infant and mother (review Table 15-10). Breast milk excels as a source of nutrients for infants. Its unique nutrient composition and protective factors promote optimal infant health and development throughout the first year of life (see Photo 16-2). Ideally, infants will receive exclusive breastfeeding for 6 months, and breastfeeding with complementary foods for at least 12 months. Experts add, though, that iron-fortified formula, which imitates the nutrient composition of breast milk, is an acceptable alternative. After all, the primary goal is to nourish the infant in a relaxed and loving environment. Chapter 15 discusses maternal nutrition to support successful breastfeeding; this section focuses on infants' nutrition.
risks of formula feeding
Infant formulas contain no protective antibodies for infants, but in general, vaccinations, purified water, and clean environments in developed countries help protect infants from infections. Formulas can be prepared safely by following the rules of proper food handling and by using water that is free of contamination. Of particular concern is lead-contaminated water, a major source of lead poisoning in infants. Because the first water drawn from the tap each day is highest in lead, a person living in a house with old, lead-soldered plumbing should let the water run a few minutes before drinking or using it to prepare formula or food. Water supplies contain variable concentrations of minerals, including fluoride. As mentioned in Chapter 13, optimal fluoride concentrations protect against dental caries, but too much fluoride during tooth development can cause structural defects and discoloration of the teeth known as fluorosis. Experts urge caregivers who use well water to have it analyzed and those who depend on the community water supply to check with local health departments to determine its fluoride content. In making formulas from powdered or concentrated liquid preparations, caregivers should reconstitute them with optimally fluoridated water (0.7 to 1.2 parts per million). If water fluoride levels are excessive, ready-to-feed formulas or formulas prepared with fluoride-free or low-fluoride water can be used. Such waters are labeled "purified," "demineralized," "deionized," or "distilled." If fluoride levels are inadequate, formulas should be prepared with fluoridated bottled water once the infant is 6 months of age. In developing countries and in the United States when family incomes fall below the poverty threshold, formula may be unavailable, prepared with contaminated water, or overdiluted in an attempt to save money. Contaminated formulas may cause infections, leading to diarrhea, dehydration, and malabsorption. Without sterilization and refrigeration, formula is an ideal breeding ground for bacteria. Whenever such risks are present, breastfeeding can be a lifesaving option: breast milk is sterile, and its antibodies strengthen an infant's defenses against infections
physical health in childhood obesity
Like adults who are overweight, children who are overweight or obese display a blood lipid profile indicating that atherosclerosis is beginning to develop—high levels of total cholesterol, triglycerides, and LDL cholesterol. Children who are overweight or obese also tend to have high blood pressure; in fact, obesity is a leading cause of pediatric hypertension. Their risks for developing type 2 diabetes and respiratory diseases (such as asthma) are also exceptionally high. These relationships between childhood obesity and chronic diseases are discussed fully in Highlight 16.
protein in childhood
Like energy needs, total protein needs increase slightly with age, but when the child's body weight is considered, the protein requirement actually declines slightly (see the inside front cover). Protein needs of children are well covered by typical US diets and well-planned vegetarian diets.
childhood obesity
Like their parents, US children are becoming obese; their numbers have increased dramatically over the past five decades. Today, an estimated 35 percent of those who are 2 to 19 years old are either overweight or obese. This statistic is based on data from the BMI-for-age growth charts, which categorizes children and adolescents as overweight at the 85th percentile and obese at the 95th percentile and above. There are exceptions to the use of the 85th and 95th percentile cutoff points. For older adolescents, a BMI at the 95th percentile is higher than a BMI of 30, the adult obesity cutoff point. Therefore, obesity is defined as a BMI at the 95th percentile or a BMI of 30 or greater, whichever is lower. For children younger than 2 years of age, BMI values are not available. For this age group, weight-for-height values above the 95th percentile are classified as overweight. How To 16-2 presents the BMI for children and adolescents, indicating cutoff points for obesity and overweight. For children 2 years of age and older, a BMI greater than or equal to 120 percent of the 95th percentile or a BMI of 35 or greater, whichever is lower, defines severe obesity in childhood. Unfortunately, severe obesity in children is becoming more prevalent. Many of these children have multiple risk factors for cardiovascular disease and high risks of severe obesity in adulthood. The special risks and treatment needs of children who are severely obese need to be recognized. The problem of childhood obesity is especially troubling because children who are overweight may become adults who are obese with all the social, economic, and medical ramifications that often accompany obesity. They have additional problems, too, involving their growth, physical health, and psychological development. In trying to explain the rise in childhood obesity, researchers point to both genetic and environmental factors.
nutrition at school
Meals at school -administered by USDA --school Breakfast Program --national School Lunch Program --nutritional adequacy - 1/3 of recommended intakes --dietary Guidelines for Americans -educational benefits -child and Adult Care Food Program (CACFP) competing influences at school -Short lunch periods and long waiting lines -Competing foods
prevention and treatment of childhood obesity
Medical science has worked wonders in preventing or curing many of even the most serious childhood diseases, but obesity remains a challenge. Once excess fat has been stored, it is difficult to lose. In light of all this, parents are encouraged to make major efforts to prevent childhood obesity starting at birth, or to begin treatment at least before adolescence. Researchers studying more than 50,000 children determined that most excessive weight gains happen early—between the ages of 2 and 6 years of age—and persist into adolescence. Table 16-9 presents guidelines to prevent obesity in children in an easy-to-remember numerical format.
hunger and malnutrition in children
Most children in the United States have access to regular meals, but hunger and malnutrition are not uncommon, especially among children in families whose income falls below the poverty threshold. An estimated 12 million US children live in households that sometimes have no food available. Chapter 20 examines the causes and consequences of hunger in the United States and around the world. Hunger and Behavior Both short-term and long-term hunger exert negative effects on behavior and health. Short-term hunger, such as when a child misses a meal, impairs the child's ability to pay attention and be productive. Hungry children are irritable, apathetic, and uninterested in their environment. Long-term hunger impairs growth and immune defenses. Food assistance programs such as the WIC program (discussed in Chapter 15) and the National School Breakfast and School Lunch Programs (discussed later in this chapter) are designed to protect against hunger and improve children's health. A nutritious breakfast is a central feature of a child's diet that supports healthy growth and development (see Photo 16-6). Children who skip breakfast typically fail to make up the deficits at later meals—they simply have lower intakes of energy, vitamins, and minerals than those who eat breakfast. Children who eat no breakfast are more likely to be overweight, may have shorter attention spans, and may be more likely to perform poorly in tasks requiring concentration, although more research is needed to substantiate these findings. Common sense dictates that it is unreasonable to expect anyone to learn and perform without fuel. For the child who hasn't had breakfast, the morning's lessons may be lost altogether. Even if a child has eaten breakfast, discomfort from hunger may become distracting by late morning. Teachers aware of the late-morning slump in their classrooms wisely request that midmorning snacks be provided; snacks improve classroom performance all the way to lunchtime. Iron Deficiency and Behavior Iron deficiency has well-known and widespread effects on children's behavior and intellectual performance. In addition to carrying oxygen in the blood, iron transports oxygen within cells, where it participates in energy metabolism. Iron is also used to make neurotransmitters—most notably, those that regulate the ability to pay attention, which is crucial to learning. Consequently, iron deficiency not only causes an energy crisis, but also directly impairs attention span and learning ability. Iron deficiency is often diagnosed by a quick, easy, inexpensive hemoglobin or hematocrit test that detects a deficit of iron in the blood. A child's brain, however, is sensitive to low iron concentrations long before the blood effects appear. Iron deficiency weakens the motivation to persist in intellectually challenging tasks and impairs overall intellectual performance. Children with anemia perform poorly on tests and are disruptive in the classroom; iron supplementation improves learning and memory. When combined with other nutrient deficiencies, iron-deficiency anemia exhibits synergistic effects that are especially detrimental to learning. Furthermore, children who had iron-deficiency anemia as infants continue to perform poorly as they grow older, even if their iron status improves. The long-term damaging effects on intellectual development make prevention and treatment of iron deficiency during infancy and early childhood a high priority. Other Nutrient Deficiencies and Behavior A child with any of several nutrient deficiencies may be irritable, aggressive, and disagreeable, or sad and withdrawn. Such a child may be labeled "hyperactive," "depressed," or "unlikable," when in fact these traits may be due to simple, even marginal, malnutrition. Parents and medical practitioners often overlook the possibility that malnutrition may account for abnormalities of appearance and behavior. Any departure from healthy appearance and behavior is a sign of possible poor nutrition. In any such case, inspection of the child's diet by a registered dietitian nutritionist or other qualified health care professional is in order. Any suspicion of dietary inadequacies, no matter what other causes may be implicated, should prompt steps to identify and correct those inadequacies immediately.
infant formula standards
National and international standards have been set for the nutrient contents of infant formulas. In the United States, the standard developed by the American Academy of Pediatrics reflects "human milk taken from well-nourished mothers during the first or second month of lactation, when the infant's growth rate is high." The FDA mandates the safety and nutritional quality of infant formulas. Formulas meeting these standards have similar nutrient compositions. Small differences among formulas are sometimes confusing, but they are usually unimportant; all support infant growth and health The FDA's quality control procedures further ensure that infant formulas are safe and support healthy growth. These standards specify how and when manufacturers must inform the FDA about new formulas and changes to formulas, and require testing for contamination with harmful bacteria such as Salmonella.
genetic and environmental factors of childhood obesity
Parental obesity predicts an early increase in a young child's BMI, and more than doubles the chances that a young child will become an adult who is obese. Children whose parents are not obese have a less than 10 percent chance of becoming obese in adulthood, whereas teens who are overweight with at least one parent who is obese have a greater than 80 percent chance of being adults who are obese. The link between parental and child obesity reflects both genetic and environmental factors (as Chapter 9 describes). Poor diet and physical inactivity are the two strongest environmental factors explaining why children are heavier today than they were 50 or so years ago. Since that time, the prevalence of childhood obesity throughout the United States more than doubled for young children and more than tripled for children 6 to 11 years of age and adolescents. As a society, our eating and activity patterns changed considerably. In many families, both parents work outside the home and work longer hours; more emphasis is placed on convenience foods and foods eaten away from home; meal choices at school are more diverse and often less nutritious; sedentary activities such as watching television and playing video or computer games occupy much of children's free time; and opportunities for physical activity and outdoor play both during and after school have declined. All of these factors and many others influence children's eating and activity patterns. Children learn food behaviors from their families, and research confirms the significant roles parents play in providing nutrient-dense foods, teaching their children about healthy food choices, and serving as role models. When parents eat fruits and vegetables frequently, their children do too. The more fruits and vegetables children eat, the more vitamins, minerals, and fiber, and the less saturated fat, in their diets. In children 2 to 18 years of age, about one third of the total energy intake comes from solid fats and added sugars—in other words—empty kcalories. The top contributors of these empty kcalories are sugar-sweetened beverages, dairy desserts (ice cream, frozen yogurt, sorbet, sherbet, pudding, and custard), grain desserts (cakes, cookies, pies, cobblers, donuts, and granola bars), pizza, and whole milk. Not surprisingly, when researchers ask "Are today's children eating more kcalories than those of 50 years ago?" the answer is yes. As Highlight 4 discusses, while the prevalence of obesity among both children and adults has surged over the past five decades, so has the consumption of added sugars and, especially, high-fructose corn syrup—the easily consumed, energy-dense liquid sugar added to soft drinks. Each 12-ounce can of soft drink provides the equivalent of about 10 teaspoons of sugar and 150 kcalories. Over the past decade, the consumption of sugar-sweetened beverages by children and adolescents has declined, but children and teens still drink too many of these high-kcalorie, sugar-sweetened beverages. More than half of school-age children consume at least one soft drink each day at school; adolescent males consume the most—two or more cans daily. Research shows, of course, that soft drink consumption is associated with increased energy intakes and body weights. While the tremendous increase in soft drink consumption plays a major role, much of the obesity epidemic can also be attributed to lack of physical activity. Children have become more sedentary, and children who are sedentary are more often overweight. Television watching may contribute most to this trend. Children 8 to 18 years of age spend an average of 4.5 hours per day watching television, and long television times are linked with overweight in children. Television fosters overweight and obesity because it: Requires no energy beyond basal metabolism Replaces vigorous activities Encourages snacking Promotes a sedentary lifestyle A child who spends more than an hour or two each day in front of a television, computer monitor, or other media can become overweight even while eating fewer kcalories than a more active child. Too much screen time and not enough activity time also contributes to a child's psychological distress. Children who have television sets in their bedrooms spend more time watching TV, less time being physically active, and less time sleeping than other children. Watching television influences food intake as well as physical activity (see Photo 16-9). Children who watch a great deal of television are most likely to be overweight and least likely to eat family meals or fruits and vegetables. They often snack on the nutrient-poor, energy-dense foods that are advertised. Child-targeted food ads on television peddle foods high in sugar, saturated fat, and salt such as sugar-coated breakfast cereals, candy bars, chips, fast foods, and carbonated beverages. More than half of all food advertisements are aimed specifically at children and market products as fun, exciting, and cool, oftentimes using sports heroes. Not surprisingly, the more time children spend watching television, the more they request these advertised foods and beverages—and their requests are granted about half of the time. The most popular foods and beverages are marketed to children and adolescents on the Internet as well, using "advergaming" (advertised product as part of a game), cartoon characters or "spokes-characters," and designated children's areas. Food marketing to children, including TV ads and Internet ads, as well as marketing to children in their local communities by way of store giveaways, restaurant promotions, school activities, and sporting events exerts a profound effect on children's nutrition and health. Despite initiatives by the food industry to respond to public health concerns about child-targeted advertising, much remains to be done to reduce the marketing of unhealthy foods to children. The physically inactive time spent watching television is second only to time spent sleeping. Children also spend more time playing computer and video games. In most cases, these activities use no more energy than resting, displace participation in more vigorous activities, and foster snacking on high-fat foods. Compared to sedentary screen-time activities, playing active video games that demand at least moderate physical activity does expend more energy and may improve physical fitness. More research is needed to ascertain whether playing active video games increases habitual physical activity or reduces sedentary behaviors. Simply shortening the amount of time spent watching television (and playing sedentary video games) can improve a child's BMI. The American Academy of Pediatrics recommends no television viewing before 2 years of age, and limiting daily screen time to one hour between 2 and 5 years of age and 2 hours for older children.
special formulas
Standard formulas are inappropriate for some infants. Special formulas have been designed to meet the dietary needs of infants with specific conditions such as prematurity or inherited diseases. Some infants allergic to milk protein can drink formulas based on soy protein. Soy formulas also use cornstarch and sucrose instead of lactose and so are also recommended for infants with lactose intolerance. They are also useful as an alternative to milk-based formulas for vegan families. Despite these limited uses, soy formulas account for about 15 percent of the infant formulas sold today. Soy formulas support the growth and development of infants, but for infants who don't need them, they offer no advantage over milk formulas. Some infants who are allergic to cow's milk protein may also be allergic to soy protein. For these infants, special formulas based on hydrolyzed protein are available. The protein in these formulas is a mixture of free amino acids, dipeptides, tripeptides, and short-chain peptides that do not elicit allergic reactions in most infants. Inappropriate Formulas Caregivers must use only products designed for infants. Soy beverages, for example, are nutritionally incomplete and inappropriate for infants. Goat's milk is also inappropriate for infants in part because of its low folate content. An infant receiving goat's milk is likely to develop "goat's milk anemia," an anemia characteristic of folate deficiency. Nursing Bottle Tooth Decay An infant must not be allowed to sleep with a bottle because of the potential damage to developing teeth. Salivary flow, which normally cleanses the mouth, diminishes as the infant falls asleep. Prolonged sucking on a bottle of formula, milk, or juice bathes the upper teeth in a carbohydrate-rich fluid that nourishes decay-producing bacteria. (The tongue covers and protects most of the lower teeth, but they, too, may be affected.) The result is extensive and rapid tooth decay (see Figure 16-5). To prevent nursing bottle tooth decay, no infant should be put to bed with a bottle of nourishing fluid.
food choices and health habits in adolescence
Teenagers like the freedom to come and go as they choose. They eat what they want if it is convenient and if they have the time. With a multitude of after school, social, and job activities, they almost inevitably fall into irregular eating habits. At any given time on any given day, a teenager may be skipping a meal, eating a snack, preparing a meal, or consuming food prepared by a parent or restaurant. Adolescents who frequently help prepare and eat meals with their families, however, eat more fruits, vegetables, grains, and calcium-rich foods, and drink fewer soft drinks, than those who seldom eat with their families. Many adolescents also begin to skip breakfast on a regular basis, missing out on important nutrients that are not made up at later meals during the day. Teenagers who eat breakfast are therefore more likely to meet their nutrient recommendations. Ideally, parents continue to play the role of gatekeepers, providing nutritious, easy-to-grab foods in the refrigerator (meats for sandwiches; low-fat cheeses; fresh, raw vegetables and fruits; fruit juices; and milk) and more in the cabinets (whole-grain breads and crackers, peanut butter, nuts, popcorn, and cereal). In many households today, adults work outside the home and teenagers help with some of the gatekeepers' tasks, such as shopping for groceries or choosing fast or prepared foods. Snacks Snacks typically provide about 25 percent of the average teenager's daily food energy intake. If chosen carefully, snacks can contribute some needed nutrients (see Table 16-13). In contrast, energy-dense, nutrient-poor snack foods can contribute to higher total energy, fat, and sugar intakes. Beverages Most frequently, adolescents drink soft drinks instead of fruit juice or milk with lunch, supper, and snacks. About the only time they select fruit juice is at breakfast. When teens drink milk, they are more likely to consume it with a meal (especially breakfast) than as a snack. Because of their greater food intakes, boys are more likely than girls to drink enough milk to meet their calcium needs. Soft drinks, when chosen as the primary beverage, may affect bone density, partly because they displace milk from the diet. Over the past three decades, teens (especially girls) have been drinking more soft drinks and less milk. Adolescents who drink soft drinks regularly have higher energy intakes and lower calcium intakes than those who do not. Soft drinks containing caffeine present another problem if caffeine intake becomes excessive. Many adolescents consume energy drinks regularly and these beverages contain much more caffeine than soft drinks. Caffeine seems to be relatively harmless when used in moderate doses (less than 100 milligrams per day, roughly the equivalent of fewer than three 12-ounce cola beverages a day). In greater amounts, however, caffeine can cause symptoms associated with anxiety, such as sweating, tenseness, and inability to concentrate. Teens with certain conditions such as diabetes, heart abnormalities, and mood disorders and those taking certain medications may encounter more severe consequences such as seizures, heart failure, and death. Eating Away from Home Adolescents eat about one-third of their meals away from home, and their nutritional welfare is enhanced or diminished by the choices they make. A lunch consisting of a hamburger, a chocolate shake, and french fries supplies substantial quantities of many nutrients at a kcalorie cost of about 800, an energy intake some adolescents can afford. When they eat this sort of lunch, teens can adjust their breakfast and dinner choices to include fruits and vegetables for vitamin A, vitamin C, folate, and fiber and lean meats and legumes for iron and zinc (see Photo 16-16). Fortunately, many fast-food restaurants are now offering more nutritious choices than the standard hamburger meal. Peer Influence Physical maturity and growing independence present adolescents with new choices. The consequences of those choices will influence their health and nutrition status both today and throughout life. Many of the food and health choices adolescents make reflect the opinions and actions of their peers. When others perceive milk as "babyish," a teen may choose soft drinks instead; when others skip lunch and hang out in the parking lot, a teen may join in for the camaraderie, regardless of hunger. Some teenagers begin using drugs, alcohol, and tobacco; others wisely refrain. Adults can set the environment so that nutritious foods are available and can stand by with reliable information and advice about health and nutrition, but the rest is up to the adolescents. Ultimately, they make the choices.
introducing cow's milk
The American Academy of Pediatrics advises that substituting cow's milk in place of breast milk or infant formula is not appropriate during the first year. For some infants, particularly those younger than 6 months of age, cow's milk may cause intestinal bleeding, which can lead to iron deficiency. Cow's milk is also a poor source of iron, so it both causes iron loss and fails to replace iron. Furthermore, the bioavailability of iron from infant cereal and other foods is reduced when cow's milk replaces breast milk or iron-fortified formula during the first year. Compared with breast milk or iron-fortified formula, cow's milk is higher in calcium and lower in vitamin C, characteristics that further reduce iron absorption. In addition, the higher protein concentration of cow's milk can stress the infant's kidneys. In short, infants need breast milk or iron-fortified infant formula as their milk source, not cow's milk. Based on updated food allergy guidelines, when infants begin complementary foods (between 4 and 6 months of age) it is acceptable to introduce cow's milk protein in the form of whole-milk yogurt or as an ingredient baked or cooked into other age-appropriate foods. Ideally, by 1 year, the infant is obtaining at least two thirds of total daily food energy from a balanced mixture of protein foods, cereals, vegetables, fruits, and other foods. At this time, whole cow's milk is an acceptable and recommended beverage to accompany a diet that supplies 30 percent of kcalories from fat. If there is concern about obesity or a family history of cardiovascular disease, reduced-fat milk can be considered starting at 1 year of age. After the age of 2, a transition to low-fat or nonfat milk can take place, but care should be taken to avoid excessive restriction of dietary fat.
energy intake and activity in adolescence
The energy needs of adolescents vary greatly, depending on the current rate of growth, sex, body composition, and physical activity. Boys' energy needs may be especially high; they typically grow faster than girls and, as mentioned, develop a greater proportion of lean body mass. An exceptionally active boy of 15 may need 3500 kcalories or more a day just to maintain his weight. Girls start growing earlier than boys and attain shorter heights and lower weights, so their energy needs peak sooner and decline earlier than those of their male peers. A 15-year-old girl who is sedentary and whose growth is nearly at a standstill may need fewer than 1800 kcalories a day if she is to avoid excessive weight gain. Thus adolescent girls need to pay special attention to being physically active and selecting nutrient-dense foods that will meet their nutrient needs without exceeding their energy needs. The problems of obesity become ever more apparent in adolescence and often continue into adulthood. Without intervention, adolescents who are overweight face numerous physical and emotional consequences. The consequences of obesity are so dramatic and our society's attitude toward thin people is so intense that even teens who are healthy-weight or underweight may perceive a need to lose weight. Data from a large national nutrition survey show that nearly 40 percent of adolescents tried to lose weight in the past year. When taken to extremes, restrictive diets bring dramatic physical consequences of their own, as Highlight 8 explains. vitamin D Several of the vitamin recommendations for adolescents are similar to those for adults, including recommendations for vitamin D. Vitamin D is essential for bone growth and development and many adolescents are at risk of vitamin D deficiency. Adolescents may need as many as 4 cups per day of low-fat or nonfat milk or other low-fat milk products to provide adequate vitamin D (and calcium) for strong bones. Adolescents who do not receive enough vitamin D from fortified foods such as milk and cereals, or from sun exposure each day, may need vitamin D supplements. iron The need for iron increases during adolescence for both females and males, but for different reasons. Iron needs increase for females as they start to lose blood through menstruation and for males as their lean body mass develops. Hence the iron RDA increases at age 14 for both males and females. For females, the RDA remains high into late adulthood. For males, the RDA returns to preadolescent values in early adulthood. In addition, iron needs increase when the adolescent growth spurt begins, whether that occurs before or after age 14. Therefore, boys in a growth spurt need an additional 2.9 milligrams of iron per day above the RDA for their age; girls need an additional 1.1 milligrams per day. Iron recommendations for girls before age 14 do not reflect the iron losses of menstruation. The average age of menarche (first menstruation) in the United States is 12.5 years; many girls younger than 14 have started to menstruate, and an additional 2.5 milligrams of iron per day is recommended for these girls. Thus the RDA for iron depends not only on age and sex but also on whether the individual is in a growth spurt or has begun to menstruate. iron intakes often fail to keep pace with increasing needs, especially for females, who typically consume fewer iron-rich foods such as meat and fewer total kcalories than males. Not surprisingly, then, iron deficiencies are most prevalent among adolescent girls. calcium Adolescence is a crucial time for bone development, and the requirement for calcium reaches its peak during these years. Unfortunately, many adolescents, especially females, have calcium intakes below recommendations. Low calcium intakes during times of active growth, especially if paired with physical inactivity, can compromise the development of peak bone mass, which is considered the best protection against adolescent fractures and adult osteoporosis. Increasing milk and milk products in the diet to meet calcium recommendations greatly increases bone density. Once again, however, teenage girls are most vulnerable because their milk—and therefore their calcium—intakes begin to decline at the time when their calcium needs are greatest. Furthermore, women have much greater bone losses in later life than men do. In addition to dietary calcium, physical activity helps bones to grow stronger (see Photo 16-15). Because some high schools do not require students to participate in physical education classes, many adolescents are not as physically active as healthy bones demand.
diet as prevention and treatment of childhood obesity
The initial goal for children who are overweight is to reduce the rate of weight gain; that is, to maintain weight as the child grows taller. Continued growth will then accomplish the desired change in BMI. Weight loss is usually not recommended because diet restrictions can interfere with growth and development. Diet and activity strategies begin with those listed in Table 16-9 and progress to more structured family meal plans when necessary. The child or the parent may be instructed to keep detailed records of dietary intake and physical activity.
physical activity as treatment and prevention of childhood obesity
The many benefits of physical activity are well known but often are not enough to motivate people, especially children, to be active. Yet regular vigorous activity can improve a child's weight, body composition, bone health, mental well-being, and physical fitness. Ideally, parents will limit sedentary activities and encourage at least 1 hour of daily physical activity to promote strong skeletal, muscular, and cardiovascular development and instill in their children the desire to be physically active throughout life. Opportunities to be physically active can include team, individual, and recreational activities. Most importantly, parents need to set a good example (see Photo 16-10). Physical activity is a natural and lifelong behavior of healthy living. It can be as simple as riding a bike, playing tag, jumping rope, or doing chores. The American Academy of Pediatrics supports the efforts of schools to include physical activity in the curriculum and encourages parents to support their children's participation.
vegetarian diets during infancy
The newborn infant consumes a lactovegetarian diet. As long as the infant has access to enough iron-fortified infant formula or breast milk (plus a vitamin D supplement) from a mother who eats an adequate diet, the infant will thrive during the early months. "Health-food beverages," such as rice milk, are inappropriate choices because they lack the protein, vitamins, and minerals infants and toddlers need. In fact, their use can lead to nutrient deficiencies. Infants older than about 6 months of age present a greater challenge in terms of meeting nutrient needs by way of vegetarian and, especially, vegan diets. Continued breastfeeding or formula feeding is recommended, but supplementary feedings are necessary to ensure adequate energy and iron intakes. Infants and young children in families who omit meat should be given iron-fortified infant cereals well into the second year. Mashed or pureed legumes, tofu, and cooked eggs can be added to their diets in place of meats. Infants who receive well-balanced vegetarian diets that include milk products and a variety of other foods can easily meet their nutritional requirements for growth. This is not always true for infants fed vegan diets: the growth of these infants slows significantly after weaning from breast milk to complementary foods. Deficiencies of protein, vitamin D, vitamin , iron, zinc, and calcium have been reported in infants fed vegan diets. Vegan diets that are high in fiber, other complex carbohydrates, and water will fill infants' stomachs before meeting energy needs. This problem can be partially alleviated by providing more energy-dense foods, such as mashed legumes, tofu, and avocado. Using soy formulas (or soy milk) fortified with calcium, vitamin , and vitamin D and including vitamin C-containing foods at meals to enhance iron absorption will help prevent some nutrient deficiencies in vegan diets. A parent or caregiver who chooses to feed an infant a vegan diet should consult with the pediatrician and registered dietitian nutritionist frequently to ensure a nutritionally adequate diet that will support growth.
mealtimes with toddlers
The nurturing of a young child involves more than nutrition. Those who care for young children are responsible not only for providing nutritious foods, milk, and water, but also a safe, loving, secure environment in which the children may grow and develop. In light of toddlers' developmental and nutrient needs and their often contrary and willful behavior, a few feeding guidelines may be helpful: Discourage unacceptable behavior, such as standing at the table or throwing food. Be consistent and firm, not punitive. For example, instead of saying "You make me mad when you don't sit down," say "The fruit salad tastes good; please sit down and eat some with me." The child will soon learn to sit and eat. Let toddlers explore and enjoy food, even if this means eating with fingers for a while. Learning to use a spoon will come in time. Children who are allowed to touch, mash, and smell their food while exploring it are more likely to accept it (see Photo 16-5). Don't force food on children. Rejecting new foods is common, and acceptance is more likely as children become familiar with new foods through repeated opportunities to taste them. Instead of saying "You cannot go outside to play until you taste your carrots," say "You can try the carrots again another time." Provide nutritious foods and let children choose which ones, and how much, they will eat. Gradually, they will acquire a taste for different foods. Limit sweets. Infants and young children have little room for empty-kcalorie foods in their daily energy allowance. Do not use sweets as a reward for eating meals. Make the dining table a place of peace. Make mealtimes enjoyable. Teach healthy food choices and eating habits in a pleasant environment. Mealtimes are not the time to fight, argue, or scold.
vitamins and minerals in childhood
The vitamin and mineral needs of children increase with age (see the inside front cover). A balanced diet of nutritious foods can meet children's needs for these nutrients, with the notable exception of iron, and possibly vitamin D. Iron-deficiency anemia is a major problem worldwide and is prevalent among US children, especially toddlers 1 to 2 years of age. During the second year of life, toddlers progress from a diet of iron-rich infant foods such as breast milk, iron-fortified formula, and iron-fortified infant cereal to a diet of adult foods and iron-poor cow's milk. In addition, their appetites often fluctuate—some become finicky about the foods they eat, and others prefer milk and juice to solid foods. These attitudes can interfere with children's eating iron-rich foods at a time that is critical for brain growth and development. To prevent iron deficiency, children's foods must deliver 7 to 10 milligrams of iron per day. To achieve this goal, snacks and meals should include iron-rich foods, and milk intake should be reasonable so that it will not displace lean meats, fish, poultry, eggs, legumes, and whole-grain or enriched products. (Chapter 13 describes iron-rich foods and ways to maximize iron absorption.) According to the DRI committee, children's intakes of vitamin D-fortified foods—including milk, ready-to-eat cereals, and juices—should provide 15 micrograms of vitamin D each day to maximize calcium absorption and ensure healthy bone growth. Children who do not meet their RDA from these sources should receive vitamin D supplements. Note that sunlight is also a source of vitamin D, especially in tropical climates and warm seasons.
food allergies
To prevent allergies and to facilitate prompt identification should they occur, experts recommend introducing single-ingredient foods, one at a time, in small portions, and waiting 3 to 5 days before introducing the next new food. For example, an infant cereal such as oatmeal may be first, followed by meats, vegetables, and fruits. If a food causes an allergic reaction (evidenced by a skin rash, digestive upset, or respiratory discomfort), it should be discontinued before introducing the next food. Food allergies in the United States have increased over the past few decades, especially allergies to peanuts. New guidelines recommend introducing peanut-based foods between 4 and 6 months of age to prevent peanut allergies. Infants at high risk—those with severe eczema or egg allergies—need medical approval and oversight, but for most other infants, parents may start adding peanut-containing foods such as watered down peanut butter or peanut puffs to the diet in the same way oatmeal and mashed vegetables are introduced. As mentioned earlier, introducing cow's milk protein in the form of yogurt or cooked into other age-appropriate foods is also acceptable, as is introducing small amounts of other commonly allergenic foods such as eggs, wheat, soy, and fish.
planning childrens meals
To provide all the needed nutrients, children's meals should include a variety of foods from each food group—in amounts suited to their appetites and needs. Table 16-6 provides USDA Food Patterns for several kcalorie levels. Estimated daily kcalorie needs for sedentary children of various ages are shown in Table 16-7. Individuals who are more physically active may need more kcalories per day. MyPlate online resources for preschoolers (2 to 5 years) translate the eating patterns into messages that can help parents ensure that the foods they provide meet their child's needs (see Figure 16-8). For older children (6 to 11 years), the site provides an interactive "Blast Off" game and other resources for teachers, parents, and children themselves. These guidelines and resources also stress the importance of balancing kcalorie intakes with kcalorie expenditures through adequate physical activity to promote growth without increasing the risks of developing obesity. Childhood obesity is the topic of a later section in this chapter. children whose diets follow the patterns presented in Table 16-6 can meet their nutrient needs fully, but many children do not eat according to these recommendations. For example, on any given day, about 30 percent of toddlers 1 to 2 years of age do not eat any vegetables. Preschool children today consume more salty snack foods, pizza, sweet snacks, candy, and fruit juices than in previous decades. On a positive note, children consume slightly more fruit than before. Overall, many children between the ages of 2 and 11 do not meet recommendations for fruits, vegetables, grains, and milk. Parents and caregivers of young children need to offer a much greater variety of nutrient-dense foods at meals and snacks to support adequate nutrition. Among other nutrition concerns for US children are inadequate intakes of vitamin E, potassium, and fiber, and excessive intakes of sodium and saturated fat.
psychological support and behavioral changesas treatment and prevention of childhood obesity
Weight-loss programs that involve parents and other caregivers in treatment report greater success than those without parental involvement. Because obesity in parents tends to correlate with that in their children, both benefit when they participate together in weight-loss programs. Parental attitudes about food greatly influence children's eating behaviors, so it is important that the influence be positive. Otherwise, eating problems may grow worse. Behavioral Changes In contrast to traditional weight-loss programs that focus on what to eat, behavioral programs focus on how to eat. These techniques involve learning new habits that lead a child to make healthy choices. Drugs The use of weight-loss drugs to treat obesity in children merits special concern because the long-term effects of these drugs on growth and development have not been studied. The drugs may be used in addition to structured lifestyle changes for carefully selected children or adolescents who are at high risk for severe obesity in adulthood. Only one prescription weight-loss medication has been approved for use in adolescents 12 years of age and older. Over the-counter weight-loss products should not be given to anyone younger than age 18.
supplements in childhood
With the exception of specific recommendations for fluoride, iron, and vitamin D during infancy and childhood, the American Academy of Pediatrics and other professional groups agree that well-nourished children need no vitamin and mineral supplements. Despite this, many children and adolescents take supplements. Researchers are still studying the safety of supplement use by children. The Federal Trade Commission has warned parents not to give supplements advertised to prevent or cure childhood illnesses such as colds, ear infections, or asthma. Dietary supplements on the market today include many herbal products that have not been tested for safety and effectiveness in children.
growth and development in adolescence
With the onset of adolescence, the steady growth of childhood speeds up abruptly and dramatically, and the growth patterns of females and males become distinct. Hormones direct the intensity of the adolescent growth spurt, profoundly affecting every organ of the body, including the brain. After 2 to 3 years of intense growth and a few more at a slower pace, physically mature adults emerge. In general, the adolescent growth spurt begins at age 10 to 11 for females and at 12 to 13 for males. It lasts about years. Before puberty, male and female body compositions differ only slightly, but during the adolescent spurt, differences between the sexes become apparent in the skeletal system, lean body mass, and fat stores. In females, fat assumes a larger percentage of total body weight, and in males, the lean body mass—principally muscle and bone—increases much more than in females (review Figure 1-1). During adolescence, males grow an average of 8 inches taller, and females, 6 inches taller. Healthy weight gain for males is approximately 45 pounds, and for females, about 35 pounds.
fats and fatty acids in childhood
no RDA for total fat has been established, but the DRI Committee recommends a fat intake of 30 to 40 percent of energy for children 1 to 3 years of age and 25 to 35 percent for children 4 to 18 years of age. As long as children's energy intakes are adequate, fat intakes less than 30 percent of total energy do not impair growth, but children who eat low-fat diets tend to have low intakes of some vitamins and minerals. Recommended intakes of the essential fatty acids are based on average intakes (see the inside front cover).
introducing complementary foods
the high nutrient needs of infancy are met first by breast milk and/or formula only and then by the limited addition of selected foods over time. Infants gradually develop the ability to chew, swallow, and digest the wide variety of foods available to adults. The caregiver's selection of foods that are suitable for each stage of development supports the infant's optimal growth and health. When to Introduce Complementary Foods In addition to breast milk or formula, an infant can begin eating complementary foods between 4 and 6 months. The American Academy of Pediatrics supports exclusive breastfeeding for 6 months but recognizes that infants are often developmentally ready to accept complementary foods as early as 4 months of age. The main purpose of introducing complementary foods is to provide needed nutrients that are no longer supplied adequately by breast milk or formula alone. The foods chosen must be those that the infant is developmentally capable of handling both physically and metabolically. As digestive secretions gradually increase throughout the first year of life, the digestion of complementary foods becomes more efficient. The exact timing depends on the individual infant's needs and developmental readiness (see Table 16-4), which vary from infant to infant because of differences in growth rates, activities, and environmental conditions.
(t/f) An infant grows fast during the first year, as Figure 16-1 shows. Growth directly reflects nutrient intake and is the major factor used to assess the nutrition status of infants and children. Health care professionals measure the height and weight of an infant or child at intervals and compare the measurements with standard growth charts for sex and age and with previous measures of that infant or child
true