Exam 4 Nutrition
How are carbohydrates, fat, and protein used to supply energy during a 100-meter sprint? During a weight-lifting session? During a 3-mile walk?
A 100-meter sprint is a short burst of intense activity; carbohydrates will primarily (about 85% of energy needs) be used to fuel the muscles with only minor contributions from fat (10%) and protein (<5%). During a weight-lifting session, most of the session is spent at rest with only short bursts of intense activity; fat supplies about 60% of energy needs, carbohydrates supply about 35%, and protein supplies about 5%. During a 3-mile walk, fat and carbohydrates will supply roughly equal amounts of calories (40 - 50%), with a minor contribution (about 5%) from protein.
Define the term food additive, and give examples of four intentional food additives. What are their specific functions in foods? What is their relationship to the GRAS list?
A food additive is a substance that has deliberately been added to food. Food additives fall into two categories: those intentionally added to foods and those that incidentally appear in foods. Some examples of intentional food additives are calcium lactate and sodium hydroxide, which both adjust the pH of foods. Alternative sweeteners such as saccharin and sucalose are also food additives. They sweeten foods without adding more than a few calories. These are all on the GRAS list, which stands for generally recognized as safe according to FDA.
Put into perspective the benefits and risks of using additives in food. Point out an easy way to reduce the consumption of food additives. Do you think this is worth the effort in terms of maintaining health? Why or why not?
Additives provide benefits such as preventing enzyme destruction of food products and improving the uniformity and smoothness of foods. However, some may also have negative effects, such as causing food sensitivities or cancer. An easy way to limit additives is to buy less processed food. A person may think, however, that this is not worth the effort because additives do much more good than harm. In addition, many substances naturally present in foods are more toxic than the small amount of synthetic food additives used in the food supply.
You have set a goal to increase muscle mass and decrease body fat. Plan a weekly fitness regimen using the FITT principle.
An example of a weekly fitness program to increase muscle mass and decrease body fat that illustrates frequency, intensity, time and type (FITT) of exercises: Sunday: Rest Monday: cardio kick-boxing class for 60 minutes (includes 10-minute warm-up, 40-minute combination of aerobic boxing and resistance exercises to achieve 70% MHR, and 10-minute cool-down) Tuesday: workout on elliptical machine for 30 minutes at 60% MHR; series of resistance exercises on weight machines, including 2 repetitions of 8 - 10 exercises that work all muscle groups; stretching exercises that work all muscle groups for 20 minutes Wednesday: cardio kick-boxing class for 60 minutes (includes 10-minute warm-up, 40-minute combination of aerobic boxing and resistance exercises to achieve 70% MHR, and 10-minute cool-down) Thursday: light jogging outdoors for 30 minutes (about 2 miles); series of resistance exercises on weight machines, including 2 repetitions of 8 - 10 exercises that work all muscle groups; stretching exercises that work all muscle groups for 20 minutes Friday: Vinyasa yoga class for 40 minutes achieving about 55% MHR Saturday: outdoor cycling for 60 minutes (about 6 miles) with a friend For progression in this exercise program, gradually increase speed of the elliptical machine, jogging, and cycling to reach a higher intensity (i.e., higher %MHR); gradually increase resistance on weight machines; and gradually increase range of motion in stretching exercises
Which types of foods are most likely to be involved in foodborne illness? Why are they targets for contamination?
Foods that are most likely to be involved in foodborne illness are those that are high in protein content, left at an unsafe temperature for a long time, and subject to cross-contamination. These foods are targets for contamination because they provide the type of environment in which viruses, bacteria, and fungi thrive.
What is the difference between anaerobic and aerobic exercise? Explain why aerobic metabolism is increased by a regular exercise routine.
Anaerobic exercise consists of short bursts of intense activity that typically only last about 30 seconds to 2 minutes. The small amount of ATP that is stored in the muscle will quickly be used to supply energy, and phosphocreatine will be used to resupply ATP. Within this short time frame of intense activity, glucose can be partially metabolized to generate some ATP. These metabolic pathways do not require oxygen. Aerobic exercise is longer in duration (> 2 minutes) and less intense, which allows time for complete and efficient metabolism of glucose, fatty acids, and amino acids to supply ATP through metabolic processes that require oxygen. A regular exercise routine induces a training effect. The number of mitochondria in muscle cells increases to allow for more efficient aerobic metabolism. The heart gets stronger and is able to pump blood more efficiently. Additional blood vessels increase the supply of oxygen and nutrients to the exercising muscles.
What are the typical characteristics of a person with anorexia nervosa? What may influence a person to begin rigid, self-imposed dietary patterns?
Anorexia nervosa is most common among adolescent females. Commonly, a person with anorexia nervosa would be described by peers as high-achieving, competitive, and perfectionist. The disorder usually starts with dieting in early puberty and proceeds to the near-total refusal to eat. Early warning signs include intense concern about weight gain and dieting, as well as abnormal food habits, such as cooking food that they won't allow themselves to eat. Research now indicates that there is a genetic predisposition for eating disorders, but they are triggered by environmental events, such as abuse, conflict, or a stressful life change.
What is the current thinking concerning use of medications for treatment of anorexia nervosa, bulimia nervosa, and binge-eating disorder?
Antidepressants are typically prescribed to treat these diseases. The concern with the medication is that these individuals have a serious problem, such that they also need psychological therapy to help develop healthy eating patterns.
How does greater physical fitness contribute to better overall health? Explain the process.
As physical activity increases, more fat is used to supply cells with energy. Physical activity also helps heart function, lessens injuries, and improves sleep habits. Overall, it promotes health in many ways.
Should competitive athletes take amino acid supplements? Why or why not?
Athletes can benefit from the ergogenic properties of a few dietary substances. These ergogenic aids include sufficient water and electrolytes, adequate carbohydrates, and a balanced and varied diet consistent with MyPlate. Protein and amino acid supplements are not among those aids because athletes can easily meet protein needs from foods. The FDA does not closely regulate dietary supplements, including amino acid supplements, so it is very difficult to know what is effective and what is not, or how much of the purported active ingredients are even present. Most adults consume 2 to 3 times as much protein as they need as part of a balanced and varied diet, so protein or amino acid supplements are not necessary. Any excess protein or amino acids will be metabolized as fuel or stored as fat and will not directly translate into increased muscle mass. For people with functional digestive tracts, there is no need to consume amino acids; the digestive tract can efficiently digest and absorb amino acids from whole proteins. Furthermore, some amino acids share common transport mechanisms, so consuming individual amino acids may cause amino acid imbalances. During endurance exercise, most of the energy supplied from protein comes from metabolism of the branched-chain amino acids: leucine, isoleucine, and valine. A normal diet provides ample branched-chain amino acids to supply this amount of fuel, so protein or amino-acid supplements are not typically needed. It is much more effective to spend time and effort on improving training routines rather than buying supplements that may or may not have any positive effect.
List five specific nutrients that athletes need and the appropriate food sources from which these nutrients can be obtained.
Athletes need a variety of nutrients to be able to achieve optimal performance. Carbohydrate intake should be at least 5 grams per kilogram of body weight. Pasta is an excellent source of carbohydrates. Fat should be consumed up to 35 percent of total calorie intake. Canola oil is an excellent source. Protein needs range from 0.8 - 1.7 grams per kilogram of body weight. Lean meat, poultry, and fish are excellent sources of protein. Iron is of special concern for female athletes. Lean meat is an excellent source of iron, as are enriched grains. Meeting the RDA for calcium is also important to support bones. Milk is an excellent source of calcium.
How does binge-eating disorder differ from bulimia nervosa? Describe the factors that contribute to the development of binge-eating disorder.
Both bulimia and binge-eating disorder involve consumption of an abnormally large amount of food within a short time. However, in binge-eating disorder, the binge is not followed by purging, as would be the case in bulimia nervosa. Deep emotional issues, such as depression resulting from abuse, are usually the underlying cause of this disease.
Describe the federal process that governs the use of food additives, including the Delaney Clause.
Both intentional and unintentional food additives are regulated by FDA in the United States. In 1958, with the Food Additives Amendment, the U.S. Congress established a list of food additives that were generally recognized as safe (GRAS) for human consumption - they had been in use for a long time and there were no reported adverse effects from consuming them. Since 1958, foods have been removed from the list (e.g., research showed red dye #3 was linked to cancer) and added to the list (e.g., new food substances have been tested and deemed safe for consumption by experts). To determine safety, food additives are tested on at least two animal species to determine the highest dose of the additive that causes no observable effects in the animals, and this maximum dose is divided by at least 100 to establish a margin of safety for human consumption. The Delaney Clause to the 1958 Food Additives Amendment prohibits use of any intentional food additive that is shown to cause cancer in laboratory animals or humans. In addition to this safety testing, food manufacturers must also provide information that identifies the new food additive, gives its chemical composition, states how it is manufactured, and specifies laboratory procedures used to measure its presence in the food supply.
Identify three major classes of microorganisms responsible for foodborne illness.
Classes of organisms responsible for foodborne illness are viruses, bacteria, fungi, and parasites.
Your neighbor is planning to run a 5-kilometer race. Summarize for her what you have learned about fluid intake before, during, and after the event.
Drink as much water 24 hours before the event as possible, even if not thirsty. Drink 1 ½ to 2 cups of fluid at least 4 hours before the event. During the event, consume fluid about every 20 to 30 minutes - enough to prevent weight loss, but not so much as to promote water weight gain during the event. After the event, 2 to 3 cups of fluid should be consumed for every pound lost.
Is fat from adipose tissue used as an energy source during exercise? If so, when?
During exercise of long duration and low intensity, fat is used to meet most energy needs. This occurs predominantly when exercise remains at a moderate rate for more than 20 minutes.
Explain the role of excessive exercise in eating disorders.
Excessive exercise may be used to purge calories if an individual feels like he or she has eaten too much. For example, a person may perform exercise for 3 hours to compensate for a binge. This can lead to many problems, including a loss of menstruation in females.
You plan to participate in a half-marathon. Plan your menu for the day of the event, being sure to include appropriate levels of macronutrients and fluids before, during, and after the athletic event.
Freely drink beverages during the 24 hours before the event to ensure adequate hydration prior to the event. In the days leading up to the event, a diet high in carbohydrates can help to maximize muscle glycogen stores. For breakfast, the goals are to supply carbohydrates to top off muscle and liver glycogen stores, prevent hunger during the event, and provide fluid for adequate hydration. This pre-event meal occurs 2 - 4 hours before the event. Road races typically take place early in the morning, so this plan provides a light breakfast just 2 hours before the event: 1 bagel with jelly and light cream cheese, 1 hard-boiled egg, 1 medium banana, and 1 cup orange juice, 1 cup water. During this endurance event, replenish fluids, carbohydrates, and electrolytes by consuming enough water and sports drinks to prevent >2% weight loss, as determined during training. For example, this athlete may consume about 2 cups per hour of sports drinks during the half-marathon. Within about 30 minutes of finishing the event, consume a snack to replenish glycogen stores and fluids. A snack rich in carbohydrates and moderate in protein is ideal for replenishing glycogen: 1 packet of Carnation Instant Breakfast mixed with 1-1/2 cups of skim milk, 1 medium banana with 2 tablespoons peanut butter. Lunch: sandwich with 1 oz turkey, 1 oz cheese, lettuce, and tomato on whole-grain bread; baby carrots with light ranch dressing; apple, 2 cups water. Snack: 1 oz pretzel rods; 1 oz cubed cheese; 1 cup water. Dinner: Mexican casserole made with brown rice, black beans, tomatoes, and cheese and topped with sliced avocado; 1 cup cooked greens; 1 cup grapes; 1-1/2 cups iced tea.
Name three nutrients often lacking in the diets of undernourished people. What effects can be expected with each deficiency?
Iron, vitamin B-12, and zinc are often lacking in the diets of individuals in developing countries. These are all mostly found in animal sources, which are scarce. These deficiencies result in anemia and poor growth and development.
Describe the difference between malnutrition and undernutrition.
Malnutrition can occur when a food supply is either scarce or abundant. The resulting deficiency conditions and degenerative diseases contribute to poor health. Undernutrition is the most common form of malnutrition in developing countries. It results from inadequate intake, absorption, or use of nutrients or food energy.
List four techniques other than thorough cooking that are important in preventing foodborne illness.
Other techniques that help avoid foodborne illness are frequent hand washing, avoiding cross-contamination, storing foods at the proper temperature, and carefully washing foods, such as vegetables
Describe how sustainable agriculture and biotechnology can improve food availability worldwide
Sustainable agriculture refers to agricultural systems that provide a stable living for farm families, maintain the natural environment, protect natural resources, support the rural community, and offer respect and fair treatment to all involved. By using farming practices that do not deplete the land, sustainable agriculture can help to ensure an adequate food supply for a growing population. In addition, by providing a stable living for farm families, sustainable agriculture bolsters small, rural economies and improves the access of farm families to food, shelter, and clean water. Biotechnology refers to processes, such as genetic engineering, that improve the characteristics of crops and livestock. Biotechnology can decrease the costs of raising food and increase yields. These changes can help to ensure an adequate food supply for a growing population. In addition, some types of biotechnology may increase certain nutrients in food. For example, golden rice, which has greater beta-carotene, vitamin C, and vitamin E content than most varieties of rice, may help to address specific nutrient deficiencies in some parts of the world.
How might parents or other role models contribute to the development of an eating disorder? Suggest an attitude that a parent or an adult friend of yours displayed that may not have been conducive to developing a healthy relationship to food.
Overall, parents are likely to have a large impact on the development of a child's eating and physical activity habits. First, parental role modeling of eating and exercise behaviors may influence a child's life-long attitudes towards food. For example, a girl who grows up with a mother who makes negative comments about her own body weight or who diets excessively may learn that a negative body image and obsessive food restriction is normal. A parent plays a huge role the development of a child's self-esteem, as well. Parents must take care not to place too much emphasis on physical appearance as a measure of self-worth. Dysfunctional family relationships may also serve as triggers for the development of eating disorders. Children exposed to conflict or abuse may overeating or refusal to eat as a way to cope with stressful situations. Parents must strike a balance between being overly permissive and being overbearing - they must let a child develop a sense of responsibility for themselves, but still maintain appropriate limits on behavior. It is very common for parents to use food as a bribe or means of comfort. For example, a parent may offer a piece of pie after dinner if the child finishes her vegetables. Forcing a child to clean his plate when he is not hungry may lead to a lifelong habit of ignoring natural hunger and satiety cues. These types of behaviors foster unhealthy relationships with food.
How important is population control in addressing the problem of world hunger now and in the future? Support your answer with three main points.
Population control is extremely important in addressing the problem of world hunger. The growth of the food supply will eventually be unable to keep up with the growth of the population. Also, population growth exceeds economic growth in many developing countries, causing an increase in poverty. Resources for the production of food such as farmland, water, fertilizer and pesticide are even becoming depleted in developing nations.
Describe some of the advances in agricultural science that are positively affecting our food supply.
Positive attitudes toward organic, local, and sustainable food production practices are on the rise and appear to be increasing the quality of diets. Organic foods are increasingly available in supermarkets, specialty stores, farmers markets, and restaurants. The organic food market received a boost in 2009 when USDA offered new funding to encourage greater production of organic food in the United States. Consumers may choose to eat organic foods to reduce their pesticide intake, to protect the environment, and out of the belief that they will improve the nutritional quality of their diets. Interest in personal and environmental health has contributed to the increasing availability and sales of organic foods. Sustainable agriculture is an integrated system of plant and animal production that will, over the long-term, satisfy human food needs, enhance environmental quality, efficiently use nonrenewable resources, sustain the economic viability of farm operations, and enhance the quality of life for farmers and society as a whole. A culture of sustainability has emerged, including a clear trend for sustainable food choices manufactured in an environmentally responsible way. Sustainable practices such as crop rotation, intercropping (growing two or more crops in proximity), as well as step farming, (also known as terrace farming), have increased productivity many fold in countries in South America. The locavore movement has gained prominence due to food-safety concerns by consumers and the search for local, sustainable foods. It encourages consumers to buy from farmers markets or produce their own food, with the argument that fresh, local products are more nutritious and taste better. A locavore is defined as someone who eats food grown or produced locally or within a certain radius, such as 50, 100, or 150 miles. Stemming from the interest in locally grown food, there is growing national support for local food collaboratives and community supported agriculture. Community supported agriculture programs (CSA) involve a partnership between local food producers and local consumers.
What three trends in food purchasing and production have led to a greater number of cases of foodborne illness?
Several purchasing and food production trends have contributed to increases in cases of foodborne illness. People are now more interested in high-protein foods in an undercooked state, such as sushi. Protein-rich foods that have not been cooked thoroughly provide an ideal growth medium for pathogens that cause foodborne illness. Consumers are demanding more foods prepared outside the home, whether from restaurants or supermarkets. Oftentimes, these foods are prepared in central kitchens and shipped out to food outlets. The number of people handling the food and the extended time these foods may spend in the danger zone present risks. Greater consumption of ready-to-eat food imported from other countries, which may not have strict food inspection standards, also increases risk for transmission of foodborne illness.
Why is solving the problem of undernutrition a key factor in the ability of developing countries to reach their full potential?
Solving the problem of undernutrition would ensure that developing countries have the human resources needed to succeed and become more independent
What are some typical measures used to assess whether an athlete's calorie intake is adequate?
Some typical methods to assess the adequacy of an athlete's diet include monitoring body weight, maintaining a food diary, or determining body fat with anthropometric measurements, such as a skinfold thickness test.
Name some substances that occur naturally in foods but may cause illness.
Substances that occur naturally in foods and may cause illness include solanine (found in potatoes), safrole (found in sassafras, mace, and nutmeg), mushroom toxins, avidin (in eggs), thiaminase (in raw fish, clams, and mussels), tetrodotoxin (found in puffer fish), oxalic acid (found in spinach), and senna or comfrey (found in some herbal teas). In the small doses normally consumed, these compounds usually produce no measurable effects, but in large doses, they can cause illness or even death.
What federal programs are available to address the problem of undernutrition in the United States?
Table 12-3 outlines twelve federally subsidized food assistance programs in the United States. Four of the most widely used programs are summarized here. The Supplemental Nutrition Assistance Program provides an EBT card for purchase of food for low-income families. The Special Supplemental Nutrition Program for Women, Infants, and Children provides vouchers for the purchase of infant formula and specific foods that are rich sources of nutrients of concern (e.g., iron, vitamin A, vitamin C) for pregnant or lactating mothers and their infants and children up to age 5. The National School Lunch Program and School Breakfast Program provide free or reduced-price lunch and breakfast for low-income, school-age children.
What do you believe are the major factors contributing to undernutrition in wealthy nations, such as the United States? What are some solutions to this problem?
The biggest problem contributing to undernutrition in the United States is poverty. Although there is an abundance of food available in the United States, impoverished people are unable to access it. One solution is to create more work, as well as study opportunities for those in low skill jobs. These could be ways to help get people on the road to self-sufficiency.
List the three components of the female athlete triad. What is the major health risk associated with loss of menstrual periods in the female athlete?
The female athlete triad consists of disordered eating, loss of menstrual periods, and osteoporosis. The loss of menstrual periods and related decline in blood estrogen greatly weakens bones, causing some young women with this disorder to have bone mineral density equivalent to that of a 60-year-old woman.
Provide an example of the way society contributes to development of eating disorders.
The media has greatly contributed to eating disorders. Magazines show only airbrushed, beautiful people, and this misleads the public into thinking that this is what people should look like.
Describe in a short paragraph any evidence of undernutrition that you saw while you were growing up, such as on television. What are or were the likely roots of these problems?
The most salient forms of undernutrition a person may have seen were on television, such as commercials soliciting sponsors to provide monetary aid to provide food (and shelter, sanitation, clothing, etc.) for children in developing countries. The biggest problems appear to be poverty and inadequate access to food.
Outline how war and civil unrest in developing countries have worsened problems of chronic hunger over the past few years.
The war and civil unrest in developing countries have greatly increased famine and hunger. These countries are already very poor, but now much of their money goes to war efforts and not food. Also, in these countries at war, it is almost impossible to get food and aid safely into the areas that need it most.
Describe four recommendations for reducing the risk of toxicity from environmental contaminants.
To reduce the risk of toxicity from environmental contaminants, know which foods pose a risk, emphasize variety and moderation in food selections, thoroughly rinse foods such as vegetables and fruits, and remove the outer leaves of leafy vegetables.
Provide two recommendations to reduce the problem of eating disorders in our society
Two possible recommendations would be to stress to young children that a variety of body shapes are normal and that a healthy lifestyle is much more important than trying to look like a fashion model.
List three long-term consequences of undernutrition during fetal development or infancy.
Undernutrition during critical stages of gestation or infancy can lead to poor growth, improper cognitive development, and impaired immune function.
List the detrimental physical effects of bulimia nervosa. Describe important goals of the psychological and nutrition therapy used to treat bulimic patients.
Vomiting as a means of purging is especially destructive to the body. It can cause severe tooth decay, stomach ulcers, irritation of the esophagus, low blood potassium, and other problems. Psychological effects of bulimia include low self-esteem and depression. Treatment of bulimia nervosa includes psychological as well as nutritional counseling. During treatment, bulimic persons learn to accept themselves and to cope with problems in ways that do not involve food. Regular eating patterns are developed as these patients begin to plan meals in a more informed, healthful manner.
Based on your knowledge of good nutrition and sound dietary habits, answer the following questions: a. How can repeated bingeing and purging lead to significant nutrient deficiencies? b. How can significant nutrient deficiencies contribute to major health problems in later life? c. A friend asks you, the nutrition expert, if it is okay to "cleanse" the body by eating only grapefruit for a week. What is your response?
a. During binges, healthy foods are not typically consumed. What nutrients are consumed may be lost during purges. Frequent vomiting leads to loss of electrolyte minerals, especially potassium. This combination of poor dietary quality and loss of important minerals may lead to significant nutrient deficiencies. Nutrient deficiencies can greatly harm growth and development. For example, if a person is continually deficient in calcium, it is very likely that he or she will develop osteoporosis later in life. Potassium imbalances may lead to heart arrhythmias. No, it is not okay to eat only grapefruit for a week. Your body needs a variety of foods to function properly; eating only grapefruit is not giving your body all of the nutrients that it needs.