Chapter 8 nutrition
liver damage
high doses of nicotonic acid can also cause _____
true
Long-term vitamin E deficiency damages the nervous system and results in nerve damage, loss of neuromuscular control, and blindness
vitamin supplements
People who are unable to absorb vitamins may need to take large oral doses of __________just to enable small amounts of the vitamins to be absorbed.
vitamin A
Miscarriage and birth defects may result when excessive amounts of _____ are taken early in pregnancy.
ascorbic acid
Most animals do not need dietary sources of vitamin C (__________) because they can synthesize all the vitamin they need. Humans and guinea pigs are among the few species that are unable to make vitamin C, and for these animals, the micronutrient is essential.
Antioxidants
Protect cells by giving up electrons to radicals
radical
Substance with an unpaired electron
mucus
Certain epithelial cells secrete _____, a sticky fluid that keeps the tissue moist and forms a barrier against many environmental pollutants and infectious agents.
Vitamins
Certain types of bacteria and algae produce _______. These organisms can be grown in laboratory settings for the purpose of "harvesting" their vitamins to use in supplement production
antibodies
Certain white blood cells produce _____, which are proteins that participate in the body's immune response. this can help destroy infectious agents such as bacteria.
keratin
Epithelial cells are among the first to become affected by a deficiency of vitamin A. In skin, vitamin A-deficient epithelial cells produce too much ______, a tough protein found in hair, nails, and the outermost layers of skin.
xerophthalmia
Eventually, the epithelial cells harden and stop producing mucus. This condition is called _______ or "dry eye." Corneas affected by this can be damaged easily by dirt and bacteria. Unless a person with xerophthalmia receives vitamin A, the condition eventually leads to blindness.
vitamin D
Fish liver oils and fatty fish, especially salmon, herring, and catfish, are among the few foods that naturally contain _______.
macula
age-related macular degeneration (AMD) is associated with with changes in the ______, the region within the eye that provides the most detailed central vision.
vitamin E
Harvesting, processing, storage, and cooking methods influence the amount of ______ retained in food.
B-12
Health experts are considering whether vitamin ________ should be included as an enrichment nutrient
rickets
vitamin D defieciency disorder in children
true
During the milling process, most of the vitamin E that is in whole grains is lost, and it is not restored by enrichment. Furthermore, vitamin E is highly susceptible to destruction by exposure to oxygen, metals, and light, as well as high temperatures that occur when heating oil for deep-fat frying.
food-cobalamin malabsorption
People with this condition develop vitamin B-12 deficiency disorder despite consuming diets that contain the vitamin. In addition to advanced age, chronic alcoholism, gastric bypass surgeries for weight reduction, and certain medications, particularly those that reduce stomach acid secretion, can contribute to __________. People with this form of malabsorption produce intrinsic factor, so they can absorb synthetic forms of the vitamin in dietary supplements that contain B-12.
Vegetables
Vitamin A precursors Vitamins K, E (carrots)
vitamin absorption
Diseases or conditions that affect the GI tract can reduce ________ and result in deficiencies of these micronutrients.
true
Vitamin C does not function as part of a coenzyme as do B vitamins, but the vitamin serves as a nutrient cofactor that facilitates certain chemical reactions.
true
Vitamin C is very unstable in the presence of heat, oxygen, light, alkaline conditions, and the minerals iron and copper. Storing vitamin C-rich foods in cool conditions, such as in the refrigerator, will help preserve the micronutrient. Because vitamin C is easily lost during cooking, eat raw fruits and vegetables whenever possible.
collagen
Vitamin C participates in reactions that form and maintain ______
nicotinic acid
megadoses of dietary supplements containing ______, a form of naicin, can reduce elevated LDL cholesterol levels and increase beneficial HDL cholesterol levels in blood.
Oxidized
When an atom or molecule loses one or more electrons, it has been
parathyroid hormone (PTH)
When blood calcium levels drop, vitamin D works with _________ to signal bones to release calcium.
hemoglobin
During red blood cell production, the coenzyme participates in the synthesis of heme. Heme is the iron-containing portion of _____, the protein in red blood cells (RBCs) that transports oxygen.
neural tube
During the first few weeks after conception, the ______forms in the human embryo. It eventually develops into the brain and spinal cord.
blind
Each year, thousands of children in developing nations, especially in Africa and Southeast Asia, become ______because of severe vitamin A deficiency.
UV radiation
Earth's atmosphere blocks _______. In North America, the 37th parallel extends from about southern Virginia through southern Missouri to San Francisco, California
heat, alkaline substances, light, and air
Exposure to excessive ________ can destroy certain vitamins, especially vitamin C.To reduce such losses, trim, peel, and cut raw fruits and vegetables just before eating or serving them. The darker leaves of vegetable greens generally contain more vitamins than the inner, paler color leaves or stems. Therefore, lightly trim away the outer leaves of lettuce and cabbage, and keep edible peels intact—just remove rotten or shriveled parts.
The body requires vitamins in milligram or microgram amounts, but needs grams of macronutrients
Food generally contain much smaller amounts of vitamins than of macronutrients
glucose, fatty acid's, and amino acids
Although the body does not use the vitamins directly for energy, many vitamins participate in the chemical reactions that release energy from
Vitamins
Although_____our organic molecules in foods, they are distinctly different from carbohydrates, fat, and proteins
true
Babies are generally born with low vitamin K stores, and a deficiency of the vitamin can occur soon after birth. Vitamin K-deficient infants are at risk of serious bleeding because their bodies are unable to make certain blood-clotting factors. To prevent vitamin K deficiency from developing during infancy, newborns generally receive a single injection of vitamin K.
true
Because many of folate's metabolic roles are related to those of vitamin B-12, diets that lack either vitamin produce a number of identical deficiency signs and symptoms. For example, being deficient in folate or vitamin B-12 can cause megaloblastic anemia.
platelets
Blood contains inactive clotting factors and cell fragments called _____that are necessary for blood clotting to occur. When a blood vessel is cut, blood in the injured area undergoes a complex series of steps to form a clot that stops the bleeding
Oxidized
By sacrificing electrons, antioxidants protect molecules such as polyunsaturated fatty acids in the membrane or DNA in the nucleus from being ___
rickets
By the 1700s, some people in parts of northern Europe had learned that exposing children to sunlight or giving the youngsters fish liver oil could prevent or treat ____.
beta-carotene
Carrots, spinach and other leafy greens, pumpkin, sweet potatoes, broccoli, mangoes, and cantaloupe are rich sources of
Vitamin E
Cells regulate oxidation reactions by using antioxidants such as
vitamin K
Major food sources of _____ are green leafy vegetables such as kale, turnip greens, salad greens, cabbage, and spinach; broccoli; and green beans.Other reliable sources of the vitamin are soybean and canola oils, and products made from these oils, such as margarine and salad dressing. The chemical structure is very stable and resists being destroyed by usual cooking methods.
true
Many nutrition experts are concerned that by substituting such human-made products for more natural foods and beverages, Americans may consume excessive amounts of a few vitamins while reducing their intake of others.
true
Many of the chemical reactions involved in the metabolism of carbohydrates, fats, and amino acids involve coenzymes that contain B vitamins.Thiamin, riboflavin, niacin, vitamin B-6, and pantothenic acid function as part of coenzymes involved in energy metabolism. Coenzymes containing these vitamins are also necessary for synthesizing glucose, amino acids, and certain lipids.
Vitamin A
Most vitamins have more than one chemical form that functions in the body. For example, retinol, retinal, and retinoic acid are chemically related types of _____ that have roles in the body
Enrichment
Helps protect Americans from developing the deficiency diseases associated with the lack of these nutrients
anemia
Hemolysis can cause _____, a disorder characterized by too few red blood cells (RBC)
True
However, enrichment does not replace the vitamin E, vitamin B-6, potassium, magnesium, several other micronutrients, and fiber that were naturally in the unrefined grains. This is the major reason dietitians and other nutrition experts promote regular consumption of whole grain products, such as whole wheat bread and brown rice
pellagra
If the affected person continues to consume a niacin-deficient diet, the condition worsens and _______develops. The classic signs and symptoms of this are dermatitis, diarrhea, dementia, and death—the "4 Ds of ___"
Oxidation
If the loss of electrons is uncontrolled, a chain reaction can occur in which excessive ______ takes place and affects many cells
True
If you are healthy and usually follow a nutritionally adequate diet, your cells should contain a supply of vitamins that can last for several days and possibly years , depending on the vitamin
true
If you have dark skin, you may need to spend even more time in the sun to form adequate amounts of the vitamin. Otherwise, you should consider consuming foods that contain the vitamin or a vitamin D supplement regularly.
true
If your usual diet is nutritionally adequate but you occasionally have low intakes of vitamins, you are unlikely to develop vitamin deficiency diseases, because your cells store these micronutrients to some extent.
vitamin D
In 1922, scientists discovered a fat-soluble factor in cod liver oil that was needed for proper bone health and preventing rickets. The scientists thought the factor that cured rickets was a vitamin, and they named the substance ____.
family history
In addition to advanced age,_______ is a risk factor for pernicious anemia.
Vitamin supplements
In addition to foods, _________ are another source of these micronutrients
rhodopsin
In dark conditions, retinal binds to a protein called opsin to form _____(visual purple)
Wernicke-Korsakoff syndrome
In the United States, the degenerative brain disorder associated with thiamin deficiency is called _________. Most cases of this syndrome occur in alcoholics, because alcohol reduces thiamin absorption and increases the vitamin's excretion
fortification and enrichment
In the United States,________ of foods have improved vitamin intakes of Americans.
thiamin
In the body, _____is used to make a coenzyme that participates in chemical reactions involved in the release of energy from carbohydrates. Additionally, containing coenzyme plays a role in the metabolism of certain amino acids, and the coenzyme may be necessary for the synthesis of neurotransmitters.
tetrahydrofolic acid
In the body, cells convert all forms of folate to a group of folate-containing coenzymes collectively called _________ or simply THFA.
vitamin K
In the early 1930s, Danish researcher Henrick Dam discovered a factor in alfalfa that played a role in blood clotting (coagulation). Dam named the factor _____ after koagulation,
true
In the early twentieth century, pellagra was widespread in the southeastern United States. Today, the disease is rare in Western societies, but it still occurs among impoverished populations in developing countries, particularly in regions of Africa, India, and China.
true
Infants who are born too early (premature infants) may have low vitamin E stores, because the vitamin is transferred from mother to fetus late in pregnancy. If premature infants develop signs of vitamin E deficiency, they can be given special infant formulas and supplements that provide the vitamin.
true
Initially, folate deficiency affects cells that rapidly divide, such as red blood cells. Mature RBCs do not have nuclei, and they live for only about 4 months. Thus, the body must replace old or worn-out RBCs constantly.
true
Major sources of vitamin B-12 in the typical American's diet are meat, milk and milk products, poultry, fish, shellfish, and eggs. Although liver is not a popular food, it is one of the richest sources of vitamin B-12. Many soy products, such as soy milk, and ready-to-eat cereals are fortified with synthetic vitamin B-12.
multivitamin supplements
Many adult Americans take ________ that contain two or more vitamins and may also supply one or more minerals
Oxidation
Many medical researchers suspect excess ____ is responsible for promoting chemical changes in cells that ultimately lead to heart attack, stroke, cancer, Alzheimer's disease, and even the aging process
true
Nobel prize winning american chemist Dr. Linus Pauling published Vitamin C and the common cold. The bestselling book established the popular belief that megadoses of Vitamin C could prevent colds. many americans take megadoses of the micronutrient when they notice the cold symptoms.
vitamin A
Normal bone growth and development also require ______. Although your bones do not appear to change their shape, they are constantly remodeled by processes that involve tearing down and rebuilding the tissues to meet the physical demands that you place on them each day; Vitamin A participates with other vitamins and minerals in the bone remodeling process.
true
Only bacteria, fungi (for example, mushrooms and molds), and algae can synthesize vitamin B-12. Animals obtain the vitamin from these sources. Plants do not make vitamin B-12; therefore, we rely almost entirely on animal foods to supply the vitamin naturally.
nervous tissue and immune system
Other roles for vitamin E include maintaining _____ function.
vitamin C, thiamin, and folate
Other vitamins—particularly ________—are easily destroyed or lost by improper food storage and cooking methods. Fresh produce is more likely to retain its natural vitamin content when stored at temperatures near freezing, in high humidity, and away from air. Therefore, you should keep most fresh fruits and vegetables in plastic packaging and chilled until you are ready to use them. Tomatoes, bananas, and garlic should be stored at room temperature. Although precut, packaged salad greens and other vegetables may be convenient to use, they are highly perishable and should be used soon after purchasing.
cystic fibrosis
People with the inherited disease _______ are unable to digest fat properly, because the disease causes blockages to form in ducts that convey pancreatic enzymes to the small intestine. As a result, it reduces fat absorption, and people suffering from the disease often develop deficiencies of fat-soluble vitamins.
isotretinoin (Retin-A)
Physicians may prescribe medications derived from vitamin A, such as ______, to treat severe acne and other skin disorders. Although these medications are less toxic than natural vitamin A, ingesting excessive amounts can produce harmful symptoms.
microwaving, steaming, and stir-frying
Quick cooking methods that involve little contact between produce and water, such as ____________, can conserve much of the vitamin content of the food.
true
RDA/AI values for Fat-Soluble Vitamins are for adults 19 to 50 years of age, excluding pregnant or breastfeeding women
true
Removing too much calcium from bones can weaken them, but calcium is essential for normal heartbeat and other muscle contractions.If bones did not supply calcium for such vital functions, a person could experience serious, even fatal consequences.
true
Riboflavin's chemical structure is fairly stable, but exposure to light causes the vitamin to break down rapidly. Therefore, riboflavin-rich foods, such as milk and milk products, should not be packaged or stored in clear glass containers.
retinal
Rods remove retinol from the bloodstream and convert it to ______.
true
Signs of Wernicke-Korsakoff syndrome include abnormal eye movements, staggering gait, and distorted thought processes. Treatment involves avoiding alcohol and obtaining thiamin injections. Without prompt treatment, people with Wernicke-Korsakoff syndrome can become disabled permanently or die.
melanin
Skin contains _____, the brown pigment that can reduce the skin's ability to produce vitamin D from sunlight. Darker skin contains more of this than lighter skin.
vitamin K
Some ______ is stored in the liver and some is incorporated in lipoproteins for transport in the bloodstream. The liver also breaks down the vitamin and eliminates the vitamin's by-products by adding them to bile.
true
Some people take the prescribed medication warfarin because their blood clots too easily. Vitamin K can interfere with warfarin's "blood-thinning" activity, so people who take the medication should not consume vitamin K supplements. Additionally, these patients should try to maintain consistent dietary intakes of the vitamin each day.
Precursors
Some vitamins have ________(provitamins) that do not function as vitamins until the body converts them into active forms
niacin and D
Some vitamins, such as _______, resist destruction by usual food storage conditions or preparation methods.
Hormones
Some vitamins, such as vitamin D, act as
Biological activity
The natural form of vitamin E has more ________, that is, it produces more effects in the body, than synthetic vitamin E
ultraviolet radiation
The body can make vitamin D when skin cells are exposed to the sun's ________(UVB, in particular), which explains why the nutrient is often called the "sunshine vitamin." The radiation converts a substance in skin that is derived from cholesterol into a prohormone (vitamin D3).
A vitamin needs the following criteria:
The body cannot synthesize the compound or make enough to maintain good health; the compound naturally occurs in commonly eaten foods; signs and symptoms of a health problem open parentheses deficiency disorder) eventually occur when the substance is missing from the diet; and good health is restored, if the deficiency disorder is treated early by supplying the missing substance
B-6
The body requires vitamin _____ to make a coenzyme needed for amino acid metabolism, including the conversion of the amino acid tryptophan to niacin and transamination reactions that form nonessential amino acids
retinol
The retina, the light-sensitive area inside each eye, contains rods and cones, specialized nerve cells that are essential for vision. Rods enable you to adapt to poorly lit environments and see objects as shades of black. Cones are responsible for color vision and function in well-lit environments. Rods and cones need vitamin A, particularly _____, to function properly.
vitamin K
The presence of dietary fat, bile, and pancreatic juice help _____ be absorbed in the small intestine.
circulatory, urinary, skeletal, and nervous system defects
The results of animal studies suggest that women who are vitamin A deficient during pregnancy may give birth to infants with ______________
true
When excess vitamin D is consumed, the small intestine absorbs too much calcium from foods and the mineral is deposited in soft tissues, including the kidneys, heart, and blood vessels. The calcium deposits can interfere with cells' ability to function and cause cellular death. Other signs and symptoms of vitamin D toxicity include muscular weakness, loss of appetite, diarrhea, vomiting, and mental confusion
true
Today, severe vitamin deficiencies are uncommon in the United States, thanks in part to modern food preservation practices, food enrichment and fortification, and the year-round, widespread availability of fresh fruits and vegetables from other countries. Many Americans, however, consume considerably less than recommended amounts of certain vitamins, particularly E, D, and the vitamin-like compound choline
melanoma
Ultraviolet radiation is a major risk for skin cancer, including _______, the most deadly form of skin cancer.
retinol
Vitamin A is actually a family of compounds that includes ______.
Fruits
Vitamin A precursors Vitamin E (mangos)
true
Vitamin C plays a role in the body's immune function, and the vitamin is necessary for the synthesis of bile and certain neurotransmitters. Vitamin C is also involved in the production of various hormones, including the "stress hormone" cortisol; adolsterone, a hormone involved in blood pressure regulation; and thyroxin, the thyroid hormone that regulates energy metabolism.
120, 90
Vitamin K: AIs for the vitamin are ___mcg/day for men and ___mcg/day for women. The AIs can be met easily be eating a salad that contains 1 cup of leafy vegetables and 2 tablespoons of salad dressing made with soybean oil.
true
Vitamin deficiency also reduces the effectiveness of the immune system, and many children suffering from vitamin A deficiency die from infections such as measles. In countries where vitamin A deficiency is widespread, public health efforts are being taken to reduce the prevalence of the condition. Such efforts include educating people about the need to eat regionally grown foods that are rich in beta-carotene and giving vitamin A injections periodically to vulnerable populations. In some countries, governments encourage food manufacturers to fortify commonly eaten foods, such as sugar and margarine, with vitamin A.
Fat-soluble vitamins
Vitamins A, D, E, and K are ________; these vitamins are in the lipid portions of foods and tend to associate with lipids in the body
Oils
Vitamins E, D, A, K D = cod liver oil, margarine K = soybean oil
Cell division and development as well as growth and maintenance of tissues
Vitamins regulate a variety of body processes, including those involved in
Chemical reactions
Vitamins such as vitamin C and thiamin participate in _____ by accepting or donating electrons
response to the sudden and dramatic reduction in light intensity.
What Is Night Blindness?
True
When a chemically unstable substance accepts an electron, it can form a more stable structure that does not pull electrons away from other compounds
Reduced
When an atom or molecule gains one or more electrons, it has been
"more" is not necessarily better
When cells are saturated with a vitamin, they contain all they need and cannot accept additional amounts of the micronutrient. When this situation occurs, continuing to take the vitamin can produce a toxicity disorder, because exposure to the excess micronutrient or its by-products can damage cells.
Lose or gain
When many biochemical reactions take place, the compounds participating in the reactions _______ electrons
true
When the mucus-secreting epithelial cells do not have vitamin A, they deteriorate and no longer produce mucus. A lack of vitamin A can also reduce fertility, because the vitamin is required for maintaining the epithelial cells that line the reproductive tracts of men and women. Vitamin A is necessary for epithelial stem cells to differentiate and mature properly
Retinol (preformed vitamin A)
_______ is the most active form of the vitamin in the body.
Vitamins
________ Play numerous roles in the body, and each of these micronutrients generally has more than one function
carpul tunnel syndrome
a painful nerve disorder that effects the wrist
alzeimers disease
elevated blood homocysteine levels may also be a marker or risk factor for _________, is characterized by a progressive decline in cognitive functioning, including memory and decision making skills
folic acid
According to medical experts, adequate _____ intake can prevent most cases of spina bifida.
Fortification
Addition of one or more nutrients to foods during their manufacturing process
not unless you are taking excessive amounts (megadoses) of vitamin supplements or consuming large amounts of vitamin-fortified foods regularly. In their natural states, most commonly eaten foods do not contain toxic levels of vitamins. Taking a "one-a-day" type of multivitamin supplement regularly is unlikely to cause toxic effects in adults, because these products usually contain less than two times the Daily Values of each micronutrient component.
Do you need to be concerned about developing a vitamin toxicity disorder?
homocysteine
Folate and vitamin B-12 also participate in _________metabolism.
anencephaly
Infants born with _______have much of their brain malformed or missing, and they usually die shortly after birth.
Fortification
Involves the addition during manufacturing of one or more vitamins to a wide array of commonly eaten foods.
Oxidizing agent or oxidant
Is a substance that removes electrons from Atoms or molecules
folate
Leafy vegetables, liver, legumes, asparagus, broccoli, and orange juice are good sources of naturally occurring _____.
true
People who eat few or no animal products should consume foods that have been fortified with vitamin B-12, such as fortified soy milk and cereals, or take supplements that supply the vitamin.
true
THFA accepts a single-carbon group, such as CH3, from one compound and transfers it to another substance. As a result, THFA participates in many chemical reactions involved in DNA synthesis and amino acid metabolism. As cells prepare to divide, they need THFA to make DNA.
homocysteine
The coenzyme that contains vitamin B-6 also helps convert a toxic amino acid, _______, to cysteine, a nonessential amino acid. If the body lacks vitamin B-6, homocysteine can accumulate in blood and may contribute to cardiovascular disease in some individuals
food-cobalamin malabsorption
Vitamin B-12 deficiency is common among older adults. As people age, HCl production in their stomachs declines. Thus, many older adults have _________ because they are unable to release vitamin B-12 from animal protein
Dairy
Vitamins A, D (if fortified)
Plants, animals, fungi, and even bacteria
_________ supply natural forms of vitamins in our diets.
beta-carotene
a carotenoid that the body can convert to vitamin A.
spina bifida
infants with severe _______ have a section of their spinal cord or a sac containing some spinal fluid bulging through an opening in their backs. Often, people with this are unable to use muscles in the lower part of their bodies, and as a result, they cannot walk independently.
age-related macular degeneration (AMD)
leading cause of blindness in the US
Vitamin A
liver, butter, fish, fish oils, and eggs; milk, yogurt, margarine, and cereals are important sources of the nutrient for Americans.
pellagra
people who eat corn as their staple food are prone to develop _____.
seven water-soluble vitamins
thiamin, riboflavin, niacin, B-6, folate, B-12, and C
hormone
vitamin D however is actually a _____
true
when vitamins are taken in large amounts they often have druglike effects on the body. vitamin excesses cause unpleasant and even dangerous side effects
20
_____ Alpha-tocopherol (vitamin E) protects polyunsaturated fatty acids in cell membranes from being damaged by radicals
Radicals
_____ are highly reactive, and they remove electrons from more stable molecules, such as proteins, fatty acids, and DNA. As a result, they can damage or destroy these molecules
Folic acid
_____ refers specifically to the synthetic form of the vitamin found in supplements and added to fortify foods.
Vitamin C
______ absorption occurs in the small intestine. As intakes of the vitamin increase, the amount absorbed decreases. The intestine, for example, absorbs 50% or less of the vitamin when intakes are 1 g or more/day. Additionally, the kidneys increase their excretion of the vitamin in response to high intakes. Therefore, taking megadoses of vitamin C may be wasteful, because such high amounts of the vitamin are not well absorbed and excesses are eliminated in urine.
Keratin
______ accumulates within the skin and makes the tissue rough and bumpy. it also forms in tissues that do not normally contain the protein, such as the cornea, the clear covering over the iris of the eye
parathyroid hormone (PTH)
______ also stimulates the kidneys to increase vitamin D production and decrease the elimination of calcium in urine. These actions help raise the level of calcium in blood to normal
Kidney
______ can filter excesses of water soluble vitamins from the bloodstream and eliminate them and urine
Kidney
______ can filter their excesses of water soluble vitamins from the bloodstream and eliminate them and urine
vitamin A
______ is involved in the visual process and carrots contain these precursors. this vitamin can multitask: it has numerous functions in the body. Furthermore, carrots are not the only source of this precursors; many fruits and vegetables are rich sources of these compounds.
Spina bifida
______ occurs when the embryo's spine does not form properly, and the bones fail to enclose the spinal cord.
Vitamin A
______ plays a role in regulating the activity of the immune system. Thus, vitamin A-deficient people are at greater risk of infections than those with adequate levels of the vitamin in their bodies.
Breast milk
_______ contains insufficient amounts of vitamin D to prevent rickets. Infants who are most likely to develop rickets are breastfed, and they have dark skin, minimal sunlight exposure, and little or no vitamin D intake
Folate
_______ is extremely susceptible to destruction by heat, oxidation, and ultraviolet light. Food processing and preparation can destroy 50 to 90% of the folate in food. By eating fresh fruits and raw or lightly cooked vegetables, you are likely to obtain most of the foods' folate content.
Vitamin absorption
_______ tends to increase when the body's needs for the micronutrients are also higher than usual. The body's requirements for vitamins generally increase during periods of growth, such as infancy and adolescence, and during pregnancy and breastfeeding.
pernicious anemia
_________ can lead to vitamin B-12 deficiency and death. Treatment involves bypassing the need for intrinsic factor and intestinal absorption, usually by providing routine vitamin B-12 injections. Furthermore, taking large doses of vitamin B-12 floods the intestinal tract with the vitamin and enables a small amount to be absorbed without the need for intrinsic factor.
Fat-soluble vitamins
___________ are chemically similar to lipids, and the vitamins are in fatty portions of food. Processes that normally occur during fat digestion facilitate the absorption of _______. For example, bile enhances lipid as well as fat-soluble vitamin absorption
Vitamin deficiency disorders
___________ generally result from inadequate diets or conditions that increase the body's requirements for vitamins, such as reduced intestinal absorption or higher-than-normal excretion of the micronutrients.
Riboflavin
_______is a component of two coenzymes that play key roles in metabolism of carbohydrates, lipids, and amino acids. Milk, yogurt, and other milk products; enriched cereals; and liver are among the best sources.
Osteomalacia
______is a risk for adults who have kidney, liver, or intestinal diseases, because these conditions may reduce both vitamin D production and calcium absorption.
Rhodopsin
____is necessary for vision in dim light. When you are in a dark environment and exposed to a small amount of light, such as moonlight, the light strikes your rods, activating rhodopsin.
osteoporosis
a condition characterized by loss of bone mass that usually occurs with aging
Carotenemia
a condition characterized by yellowing of the skin, can result from eating too much beta-carotene-rich produce or taking too many beta-carotene supplements. This condition occasionally develops in infants who eat a lot of baby foods that contain carrots, apricots, winter squash, or green beans. In most instances, carotenemia is harmless. The skin's natural color eventually returns to normal when the carotenoid-rich foods are no longer eaten.
fibrin
A clot is comprised of strands of the protein _____that traps blood cells, forming a mesh.
Vitamin
A complex organic compound that regulates certain metabolic processes in the body
true
A diet that contains adequate amounts of a wide variety of foods, including minimally processed fruits, vegetables, and whole-grain breads and cereals, can help supply the vitamin needs of most healthy people.
carotenoids
A few ______are vitamin A precursors, because the body can use them to make some retinol.
alcoholics, older adults, and patients who are hospitalized for lengthy periods.
A few segments of the population have a high risk of vitamin deficiencies. These vulnerable people include
body fat, skeletal muscle, and the liver.
A healthy body stores the vitamin in 3 places
genetic makeup
A plant's vitamin content is largely determined by its ______; growing conditions including soil composition and sunlight exposure; and maturity when harvested.
folate
A pregnant woman has an increased requirement for _______, because DNA synthesis and cell division take place at a rapid pace during embryonic development.
hemolysis
A vitamin E deficiency can result in red blood cell (RBC) membranes that are vulnerable to damage by oxidizing agents. When damaged, red blood cell membranes break easily, and the cells undergo _______, that is, they break apart and die.
true
Absorbing the vitamin B-12 that is naturally in food requires a complex series of steps that are unique for a vitamin. Natural vitamin B-12 is bound to animal protein that prevents its absorption. When the food enters the stomach, the vitamin is released from the protein, primarily by the actions of hydrochloric acid (HCl) in gastric juice.
true
According to the Food and Drug Administration (FDA), microwave cooking does not reduce the nutrient content of foods any more than do conventional cooking methods. Microwave cooking may help conserve more vitamins in food because the method cooks quickly and without the need to add much water.
true
Activation alters the shape of the retinal portion of rhodopsin and bleaches the compound. This process causes retinal to split away, reforming opsin. The transformation of rhodopsin to opsin stimulates the rod to send a nervous impulse to the brain that signals the visual processing areas to interpret what is seen. After splitting away from opsin, retinal can bind to the protein, forming rhodopsin again.
Enrichment
Addition of specific amounts of thiamine, riboflavin, folic acid, and iron to refined flour and cereals
anorexia nervosa
Additionally, people who suffer from__________, have intestinal conditions that interfere with vitamin absorption, or have rare metabolic defects that increase their vitamin requirements are more likely to develop vitamin deficiency disorders than people who do not have these conditions.
energy
Advertisements for vitamins often promote the notion that the micro nutrients can give you energy. Vitamins, however are not a source of __________, because cells do not metabolize them for energy
Vitamin A
All cells in the body need vitamin A to develop and function properly. ________ participates in the processes of cell production, growth and development, function, and maintenance.
vitamin A
Although lutein, zeaxanthin, and lycopene are carotenoids, the body does not convert them to ____. Nevertheless, these plant pigments may function as beneficial antioxidants in the human body.
perishable
many kinds of produce, especially berries and leafy vegetables, are highly ________. Therefore, these foods should be eaten as soon as they are harvested or purchased to ensure maximum vitamin retention. In many instances, unpackaged ("bulk") fresh fruits or vegetables that are sold in supermarkets do not have dates indicating when they should be used, and consumers have no way of knowing when the produce was harvested.
true
Are fresh fruits and raw vegetables better sources of vitamins than canned or frozen versions? Sometimes they are.During the canning process, the heating of food can cause the destruction of certain vitamins. However, produce that is frozen immediately after being harvested and then properly stored can be just as nutritious as fresh produce. Frozen fruits and vegetables are often economical alternatives to fresh produce, but they need to be cooked without thawing to conserve much of their vitamin content. The thawing process causes some of the water that was naturally in the produce to drip out, taking water-soluble vitamins with it. If this water is discarded, vitamins in the fluid are lost.
true
Babies who consume only vitamin B-12-deficient breast milk are likely to develop megaloblastic anemia and serious nervous system problems, including diminished brain growth and spinal cord damage
Biotin and vitamin K
Bacteria that reside in your lower intestinal tract produce certain vitamins, particularly ________, and you can absorb these micronutrients to some extent. Additionally your body can synthesize vitamin D and niacin under certain conditions
true
Cells require vitamin B-12 to make coenzymes that participate in a variety of cellular processes, including the transfer of CH3 groups in the metabolism of folate. Vitamin B-12 is also needed to convert folate to coenzyme forms that are needed for metabolic reactions, including DNA synthesis. Vitamin B-12 also participates in homocysteine metabolism.
Milling (refinement)
Cereal grains such as wheat, rice, and corn lose considerable amounts of their natural vitamin contents during
true
Darkly pigmented fruits and vegetables usually contain more beta-carotene and other provitamin A carotenoids than lightly colored produce.For example, carrots, sweet potatoes, mangoes, and peaches contain more beta-carotene than celery, white potatoes, apples, and bananas. Dark green fruits and vegetables also contain carotenoids, but their green pigment chlorophyll contents hide the yellow-orange pigments.
true
using a sunscreen, limits skins ability to synthesize prohormone Vitamin D. To allow body to synthesize vitamin D wait 15 minutes before applying sunscreen
folic acid, folacin
"Folate" is the name for a group of related compounds that includes _____ and _____.
carotenoids
Although retinol and the other forms of vitamin A are only in animal foods, plants contain hundreds of yellow-orange pigments called ________.
scurvy
Americans rarely develop ______because vitamin C is added to many processed foods, including fruit and sports drinks, ready-to-eat cereals, and nutrition or power bars. If you would still like to take a vitamin C supplement daily, consider choosing a product that provides 50 to 100 mg of the vitamin in each tablet.
Radical
An oxidation reaction can form a _____, a substance with an unpaired electron
true
Foods that contribute thiamin to American diets include whole-grain and enriched breads and cereals, pork, legumes, and orange juice. Brewer's yeast is a rich source of thiamin, but most Americans do not eat the product.Overcooking and cooking food in alkaline solutions can destroy thiamin.
700 to 900
For adults, the RDA for vitamin A is _______ mcg RAE. Deficiencies of the vitamin are rare in the United States.12 Preschool children who do not eat enough vegetables, urban poor, older adults, and people with severe alcoholism, fat malabsorption, or liver diseases are at risk for vitamin A deficiency.
rare
For adults, the RDA for vitamin E is 15 mg/day of alpha-tocopherol. Although many American adults do not consume recommended amounts of vitamin E, vitamin E deficiency is
oxalate
Furthermore, when cells are saturated with vitamin C, the excess vitamin and _______, a by-product of breaking down vitamin C, circulate in the bloodstream. The kidneys filter and eliminate these unnecessary substances in urine. Excess oxalate excretion raises the risk of kidney stones.35 Therefore, people who are susceptible to develop such stones should avoid consuming vitamin C supplements.
Damaged plant cells release an enzyme that results in the production of brown pigments when it is exposed to air. The action of this enzyme can be reduced by sprinkling salt or sugar on cut pieces of raw food; coating the pieces with an acidic solution, such as lemon juice; or covering them with airtight plastic wrap and chilling the food. Because heat destroys the enzyme, the unappetizing discoloring won't occur if you cook the fruit or vegetable immediately after peeling.
Have you ever wondered why a freshly peeled apple, eggplant, potato, or banana eventually turns brown?
bile
In the small intestine, the presence of fat stimulates the secretion of a hormone that causes the gallbladder to release _____. Therefore, adding a small amount of fat to low-fat foods, such as tossing raw vegetables with some salad dressing, adding a pat of soft margarine to steamed carrots, or stir-frying green beans in peanut oil, can enhance your intestinal tract's ability to absorb the fat-soluble vitamins in these foods.
intrinsic factor (IF)
In the small intestine, vitamin B-12 binds to _________, a compound produced by certain stomach cells. Eventually, the vitamin B-12/intrinsic factor complex reaches the ileum of the small intestine, where the vitamin complex is absorbed.
True
International units (IU) has been replaced by more precise milligram or microgram measures . Food composition tables and the information panels on food and supplement labels often still list IU values for fat soluble vitamins
true
Liver, meat, fish, and poultry are among the best dietary sources of vitamin B-6. Additionally, potatoes, bananas, spinach, sweet red peppers, and broccoli are good sources of vitamin B-6.
prooxidant
Taking excessive amounts of vitamin C may be harmful, because in high doses, the vitamin has prooxidant effects. A ________ promotes radical production
true
The Mexican practice of soaking corn kernels in lime water before using them to prepare tortillas helps free the niacin, enhancing its ability to be absorbed.
liver
The UL for vitamin A intake is 3000 mcg/day for adults. Excessive consumption of vitamin A can damage the ______, because the organ is the main site for vitamin A storage. Toxicity signs and symptoms include headache, nausea, vomiting, visual disturbances, hair loss, bone pain, and bone fractures.
dietary folate equivalents
The folate content of foods may be reported as micrograms of ___________ (DFEs). DFE units account for differences in the body's ability to absorb folic acid and natural forms of folate.
beriberi
The thiamin deficiency disease is called ______. People suffering from this are very weak and have poor muscular coordination The severe lack of thiamin also negatively affects the functioning of the cardiovascular, digestive, and nervous systems.
Synthetic folic acid
The type of folate that is added to flour and many ready-to-eat and cooked cereals, has almost twice the biological activity as the natural form of the vitamin
True
The vitamins that are added may or may not be in the food naturally. For example, milk is often fortified with vitamins A and D, and many ready-to-eat cereals are sprayed with addition vitamins before packaging.
myelin sheaths
There is one vital function of vitamin B-12 that does not involve folate—maintaining the _______ that wrap around parts of certain nerve cells, insulating them. Myelin enables the nerves to communicate effectively. Without vitamin B-12, segments of myelin sheath gradually undergo destruction that can lead to paralysis. If a person who is vitamin B-12 deficient does not obtain treatment with the vitamin, he or she can die as a result of the deficiency.
megaloblastic anemia
This condition, called _________ , is characterized by large, immature RBCs (megaloblasts) that still have nuclei and do not carry normal amounts of oxygen
true
Vitamin C performs a variety of important cellular functions, primarily by donating electrons to other compounds. In the body, vitamin C has widespread physiological roles; the following sections describe some of the micronutrient's most well-understood functions.
calcium phosphate
Vitamin D also stimulates bone cells to form ________, the major mineral compound in bone. Without adequate vitamin D, bone cells cannot deposit enough calcium and phosphorus to produce strong bones
true
Vitamin D is necessary for the metabolism of the minerals calcium and phosphorus, and the production and maintenance of healthy bones. Vitamin D also stimulates small intestinal cells to absorb calcium and phosphorus from food.
true
Vitamin D is not widespread in food; therefore, your body depends on sun exposure to synthesize the vitamin. The amount of time you need to spend in the sun to form adequate amounts of vitamin D depends primarily on your location, the time of day and year, and your age and skin color.
Protein
Vitamin E - nuts, seeds, sardines Vitamin A - liver and eggs Vitamin D - salmon, egg yolk, liver
Grains
Vitamin E - wheat germ, whole grains, whole grain or fortified ready to eat cereals
alpha-tocopherol
Vitamin E has several forms, but only the _______ form is maintained in plasma and used by the body.
osteocalcin
Vitamin K also helps bone-building cells produce _______, a protein needed for normal bone mineralization. Low blood levels of vitamin K are associated with the risk of osteoporosis, a condition characterized by bones with low mineral density. However, more research is needed to clarify the vitamin's role in bone health.
The body generally has more difficulty eliminating excess fat soluble vitamins because these nutrients do not dissolve in water he substances such as urine. As a result, the body stores extra fat soluble vitamins, primarily in the liver and in body fat; water soluble vitamins are generally not as toxic as fat soluble vitamins
Why is it important to know the difference between fat and water soluble vitamins
carotenoids
common ______ include lutein, zeaxanthin, and lycopene. Green, leafy vegetables, such as spinach and kale, have high concentrations of lutein and zeaxanthin.Tomato juice and other tomato products, including pizza sauce, contain considerable amounts of lycopene.
true
Within the absorptive cells, vitamin B-12 is separated from intrinsic factor and attached to transport molecules. The transport molecules enter the bloodstream and travel to the liver via the hepatic portal vein. The liver removes vitamin B-12 from many of the carrier molecules and stores about 50% of the vitamin. A healthy liver has enough vitamin B-12 reserves to last 5 to 10 years.31 Therefore, a healthy person who decides to follow a diet that completely lacks vitamin B-12 is not likely to experience signs and symptoms of the vitamin's deficiency disorder for as long as 10 years.
Radicals
____ stimulate normal cell growth and division. Additionally, white blood cells generate this as part of their activities that destroy infectious agents
Water-soluble
__________vitamins can leach out of food and dissolve in the cooking water, which is often discarded.By cooking vegetables in small amounts of water and reusing that water for soups or sauces, you are likely to consume those water--soluble nutrients. When preparing produce for cooking, cut the food into large pieces to reduce the amount of surface area that will be exposed to heat, water, and other conditions that can increase vitamin losses. Whenever possible, cook fruits and vegetables in their skins, and if the skins are edible, eat them too.
Collagen
_______is a fibrous protein that gives strength to connective tissue. Connective tissues, such as bone, cartilage, and tendons, connect and support other structures in the body. During this formation, vitamin C helps create numerous cross-connections between the amino acids in collagen that greatly strengthen the connective tissue
tobacco
scientific evidence links _____ use to several forms of cancer, heart disease, AMD, and other serious chronic diseases
flavored drinks
some food manufacturers add vitamins to foods and beverages, particularly ________, that would otherwise be considered "empty-calorie" items.
wrinkles and skin cancer
tanning and severe sunburn increase the risk of developing ___.
retinol
vitamin A precursors in plant foods are not as well absorbed as ______in animal foods.
improper handling or lengthy storage conditions
Fresh fruits and vegetables can lose substantial amounts of vitamins as a result of ___________. Therefore, select fresh produce carefully when buying it in grocery stores.Avoid produce that is bruised, wilted, or shriveled, or shows signs of decay such as mold.
south
If you live ____of the 37th parallel and are outdoors for about 5 to 30 minutes when sunlight is most intense (between 10 a.m. and 3 p.m.)
vitamins
In other cases, physicians inject _____into their patients' bodies, completely bypassing the need for the intestine to absorb the micronutrients
coenzyme
In the body, most water-soluble vitamins function as components of specific coenzymes. A ______is a cofactor, an ion or small molecule that interacts with enzymes and, as a result, regulates a chemical reaction.
pernicious ("deadly") anemia
In these cases, diets may supply adequate amounts of vitamin B-12, but the lack of intrinsic factor prevents most of the micronutrient from being absorbed. Eventually, people who lack intrinsic factor develop a disease called _________
true
Plant foods are the best dietary sources of vitamin C. Peppers, citrus fruit, papaya, broccoli, cabbage, and berries contain relatively high amounts of the micronutrient
premenstraul syndrome (PMS)
Popular sources of nutrition information often recommend large doeses of vitamin B-6 to treat ________, a condition that many women experience a few days before their menstrual period begins
spina bifida, anencephaly
Pregnant women who suffer from folate deficiency have high risk of giving birth to infants with neural tube defects. The two most common neural tube defects are _______ and ______
true
Rich food sources of vitamin E include sunflower seeds, almonds, and plant oils, especially sunflower, safflower, canola, and olive oils. Products made from vitamin E-rich plant oils—margarine and salad dressings—also supply the micronutrient. Other important dietary sources of the vitamin include fish, whole grains, nuts, seeds, and certain vegetables. Meats, processed grain products, and dairy products generally do not contain much vitamin E.
true
Store canned foods in a cool place.Canned foods can vary in the amount of nutrients they contain, largely because of differences in storage times and temperatures. If the can has been on the shelf for an extended period of time, the food's vitamin content may have deteriorated and its taste and texture may be less than desirable. To get maximal nutritive value from canned vegetables, drain the liquid that is packed with the food and use it as a base for soups, sauces, or gravies. If the liquid is too salty, discard it.
atherosclerosis
Such oxidative damage may be associated with the development of _______, the process that occurs within arteries and contributes to heart attack and stroke; cancer; and premature cellular aging and death.
small intestine
The _______ is the primary site of vitamin absorption. However, it does not absorb 100% of the vitamins in food.
cornea
The _____enables light to enter the eye. The epithelial cells that line the inner eyelids secrete mucus that helps keep the cornea moist and clean. In a person suffering from chronic vitamin A deficiency, these cells accumulate keratin, and the white of the eye develops "foamy" areas
osteomalacia
The adult form of rickets is called _______ The bones of people with this have normal amounts of collagen, the protein that provides structure for the skeleton, but they contain less-than-normal amounts of calcium. The bones are soft and weak, and break easily as a result. Muscle weakness is also a symptom
niacin
The body uses _____to synthesize two coenzymes that participate in at least 200 reactions, including those involved in the release of energy from macronutrients. Major food sources of this include enriched cereals, beef liver, tuna, salmon, poultry, pork, and mushrooms. The chemical structure of this is very heat stable, so food retains much of its niacin content during usual preparation and cooking methods.
Enrichment
The federally regulated _______ program specifies amounts of four B vitamins (Thiamin, riboflavin, niacin, and folic acid) and the mineral iron that manufactures must add to their refined flour and other milled grain products
true
The likelihood of developing a deficiency disease increases when a person's diet consistently lacks the vitamin. When this happens, the person's body stores or tissue levels of the vitamin become depleted, and the signs and symptoms of the nutrient's deficiency disease begin to occur. A person, for example, can become vitamin C-deficient after about a month of consuming a diet that lacks the vitamin
Water-soluble vitamins
Thiamin, riboflavin, niacin, vitamin B-6, pantothenic acid, folate, biotin, vitamin B-12, and vitamin C are ________; they dissolve in the watery components of food and the body
DNA
To keep up with their rapid rate of cell division, the precursor cells that mature into RBCs must actively synthesize ___.
true
To replace the retinal, rods remove some retinol (vitamin A) from the bloodstream and convert it to retinal. Night blindness, the inability to see in dim light, occurs if retinol is unavailable. Night blindness is an early sign of vitamin A deficiency. Although cone cells also need vitamin A to function, the inability to see certain colors (color blindness) is not the result of a vitamin A deficiency.
coenzyme
To synthesize a ______, cells combine one of the B vitamins with a nitrogen-containing, nonprotein compound. When activated by the coenzyme, the enzyme enables the reaction to occur
true
Tomatoes are a good source of certain carotenoids, particularly beta-carotene and lycopene.Exposure to heat can break down plant cells, and as a result, the cells release carotenoids. Thus, cooking tomatoes can improve the intestinal tract's ability to absorb carotenoids in the food.
true
Vitamin B-12 deficiency is characterized by nerve damage and megaloblastic RBCs. Other common signs and symptoms of the deficiency include muscle weakness, sore mouth, smooth and shiny tongue, memory loss, confusion, difficulty walking and maintaining balance, and numbness and tingling sensations, particularly in the lower extremities.
neurotransmitters
Vitamin B-6 is also involved in the synthesis of _______, chemicals that nerves produce to transmit messages.
true
Vitamin K deficiency, however, can develop in people who have liver diseases or conditions that impair fat absorption, such as cystic fibrosis. Additionally, long-term antibiotic therapy can reduce the number of bacteria in the colon that synthesize vitamin K and, as a result, contribute to a deficiency of the nutrient. The most reliable sign of vitamin K deficiency is an increase in the time it takes for blood to clot.
epithelial cells
the vitamin (Vitamin A) is necessary for the production and maintenance of _______, cells that form protective tissues that line the body, including skin and linings of the digestive, respiratory, and reproductive tracts
