7 8 nutrition
Which vitamin supplement is known to cause malformations of a fetus?
. vitamin A
Choline is needed in the diet, but it is not a vitamin. Many U.S. adults do not consume the DRI amount of choline, but effects on health are uncertain. Many other substances that people claim are vitamins are not.
7-10iNon-B Vitamins
Fat-soluble vitamins, like other lipids, are mostly absorbed into the lymph, and they travel in the blood and within the cells in association with protein carriers.Fat-soluble vitamins can be stored in the liver or with other lipids in fatty tissues, and some can build up to toxic concentrations.
7-1b fat soluble and water soluble
rhodopsin
Definition:(roh-DOP-sin) the light-sensitive pigment of the cells in the retina; it contains vitamin A (opsin means "visual protein").
tocopherol
Definition:(tuh-KOFF-er-all) a kind of alcohol. The active form of vitamin E is alpha-tocopherol.
xerosis
Definition:(zeer-OH-sis) drying of the cornea; a symptom of vitamin A deficiency.
Deficiencies of the fat-soluble vitamins occur when the diet is consistently low in them. They also occur in people who undergo intestinal surgery for obesity treatment, which reduces energy nutrient absorption by design and vitamin absorption unintentionally. We also know that any disease that produces fat malabsorption (such as liver disease, which prevents bile production) can cause the loss of vitamins dissolved in undigested fat and so bring on deficiencies. In the same way, a person who uses mineral oil (which the body cannot absorb) as a laxative risks losing fat-soluble vitamins because they readily dissolve into the oil and are excreted with it. Deficiencies are also likely when people follow eating patterns that are extraordinarily low in fat because a little fat is necessary for absorption of these vitamins.
7-2 fat soluble vitamins
Three active forms of vitamin A and one precursor are important in nutrition. Vitamin A plays major roles in gene regulation, eyesight, reproduction, cell differentiation, immunity, and growth.
7-3B vit a toxicity, deficiency, table
tru
Active forms of vitamin A that are readily absorbed in the body are only found in foods derived from animals.
Vitamin C in variously processed orange juice makes a convenient example: Fresh squeezed, not from concentrate. Juice extracted from the fibrous structures of whole oranges is quickly packaged, pasteurized, and refrigerated. (Almost all of the vitamin C is retained: 8 ounces provides 120 milligrams of vitamin C.) Reconstituted, made from concentrate. Fresh-squeezed juice is condensed by heat and pressure, and then frozen. After being reconstituted by adding water, it is packaged in cartons and refrigerated. The concentrate may also be sold frozen for reconstituting at home. (Condensing destroys a small amount of vitamin C: 8 ounces of reconstituted juice provides 97 milligrams of vitamin C.) Canned 100% orange juice. Fluid juice, most often reconstituted, is heated to sterilize it during canning. (Heating destroys more vitamin C: 8 ounces provides 75 milligrams of vitamin C.)
After harvest, cellular enzymes in fruit and vegetables continuously break down vitamins, causing significant losses over time. Freezing dramatically slows this enzymatic breakdown, and preserves almost all of the vitamins present at harvest. As for canning, it requires heating foods to a high enough temperature for long enough to destroy any illness-causing microbes that may be present. This heating process also denatures enzymes and so stops enzymatic vitamin destruction. However, heating itself destroys a small amount of vitamins, and about half of the water-soluble vitamins dissolve into the canning liquid, which is typically discarded. This doesn't make canned foods poor choices for vitamin nutrition—they can be good sources, particularly if their liquid is consumed—and they are inexpensive, convenient to store, and easily prepared.
Copper is needed to form hemoglobin and collagen, and assists in many other body processes. Copper deficiency is rare.
All of the trace minerals are toxic in excess.
7-3d beta carotene
Beta-carotene is one of many dietary antioxidants present in foods. Others include vitamin E, vitamin C, the mineral selenium, and many phytochemicals (
Magnesium Magnesium qualifies as a major mineral by virtue of its dietary requirement, but only about 1 ounce is present in the body of a 130-pound person, over half of it in the bones. Most of the rest is in the muscles, heart, liver, and other soft tissues, with only 1 percent in the body fluids. The body can tap the supply of magnesium in the bones to maintain a constant blood level whenever dietary intake falls too low. The kidneys can also act to conserve magnesium. Roles in the Body Like phosphorus, magnesium is critical to many cell functions. Magnesium: Serves as a cofactor for hundreds of enzymes. Is needed for the release and use of energy from the energy-yielding nutrients. Is a necessary part of the cellular protein-making machinery. Is critical to normal nerve transmission, muscle contraction, and heart function. Magnesium and calcium work together for proper functioning of the muscles: calcium promotes contraction and magnesium helps relax the muscles afterward. In the teeth, magnesium promotes resistance to tooth decay by holding calcium in tooth enamel. Like most other nutrients, magnesium supports the normal functioning of the immune system.
DRI Men (19-30 yr): 400 mg/day Women (19-30 yr): 310 mg/day Tolerable Upper Intake Level Adults: 350 mg/day Chief Functions Bone mineralization, enzyme action, heart function, immune function, muscle contraction, nerve function, protein synthesis, and tooth maintenance Deficiency Weakness, confusion; if extreme, convulsions, uncontrollable muscle contractions, hallucinations, and difficulty in swallowing; in children, growth failure Toxicity From nonfood sources only; diarrhea, pH imbalance, dehydration
biotin
Definition:(BY-o-tin) a B vitamin; a coenzyme necessary for fat synthesis and other metabolic reactions.
carotenoids
Definition:(CARE-oh-ten-oyds) members of a group of pigments in foods that range in color from light yellow to reddish orange and are chemical relatives of beta-carotene. Many have a degree of vitamin A activity in the body.
cretinism
Definition:(CREE-tin-ism) severe mental and physical retardation of an infant caused by the mother's iodine deficiency during pregnancy.
folate
Definition:(FOH-late) a B vitamin that acts as part of a coenzyme important in the manufacture of new cells. The form added to foods and supplements is folic acid.
phytates
Definition:(FYE-tates) compounds present in plant foods (particularly whole grains) that bind iron and may prevent its absorption.
goiter
Definition:(GOY-ter) enlargement of the thyroid gland due to an iodine deficiency is goiter; enlargement due to an iodine excess is toxic goiter.
heme
Definition:(HEEM) the iron-containing portion of the hemoglobin and myoglobin molecules.
hepcidin
Definition:(HEP-sid-in) a hormone secreted by the liver in response to elevated blood iron. Hepcidin reduces iron's absorption from the intestine and its release from storage.
keratin
Definition:(KERR-uh-tin) the normal protein of hair and nails.
choline
Definition:(KOH-leen) a nutrient used to make the phospholipid lecithin and other molecules.
cornea
Definition:(KOR-nee-uh) the transparent hard, outer covering of the front of the eye.
myoglobin
Definition:(MYE-oh-globe-in) the oxygen-holding protein of the muscles (myo means "muscle").
osteomalacia
Definition:(OS-tee-o-mal-AY-shuh) the adult expression of vitamin D-deficiency disease, characterized by an overabundance of unmineralized bone protein (osteo means "bone"; mal means "bad"). Symptoms include bending of the spine and bowing of the legs.
osteopenia
Definition:(OS-tee-oh-PEE-nee-ah) a condition of low bone mass that often progresses to osteoporosis.
Pantothenic Acid
Definition:(PAN-to-THEN-ic) a B vitamin and part of a critical coenzyme needed in energy metabolism, among other roles.
retina
Definition:(RET-in-uh) the layer of light-sensitive nerve cells lining the back of the inside of the eye.
riboflavin
Definition:(RIBE-o-flay-vin) a B vitamin active in the body's energy-releasing mechanisms.
Thiamin
Definition:(THIGH-uh-min) a B vitamin involved in the body's use of fuels.
beriberi
Definition:(berry-berry) the thiamin-deficiency disease; characterized by loss of sensation in the hands and feet, muscular weakness, advancing paralysis, and abnormal heart action.
cell differentiation
Definition:(dih-fer-en-she-AY-shun) the process by which immature cells are stimulated to mature and gain the ability to perform functions characteristic of their cell type.
epithelial tissue
Definition:(ep-ith-THEE-lee-ull) the layers of the body that serve as selective barriers to environmental factors. Examples are the cornea, the skin, the respiratory tract lining, and the lining of the digestive tract.
fluorapatite
Definition:(floor-APP-uh-tight) a crystal of bones and teeth, formed when fluoride displaces the "hydroxy" portion of hydroxyapatite. Fluorapatite resists being dissolved back into body fluid.
fluorosis
Definition:(floor-OH-sis) discoloration of the teeth due to ingestion of too much fluoride during tooth development. Skeletal fluorosis is characterized by unusually dense but weak, fracture-prone, often malformed bones, caused by excess fluoride in bone crystals.
hydroxyapatite
Definition:(hi-DROX-ee-APP-uh-tight) the chief crystal of bone and teeth, formed from calcium and phosphorus.
lipoic acid
Definition:(lip-OH-ic) a nonessential nutrient.
pellagra
Definition:(pell-AY-gra) the niacin-deficiency disease (pellis means "skin"; agra means "rough"). Symptoms include the "4 Ds": diarrhea, dermatitis, dementia, and, ultimately, death.
pernicious anemia
Definition:(per-NISH-us) anemia a vitamin B12-deficiency disease, caused by lack of intrinsic factor and characterized by large, immature red blood cells and damage to the nervous system (pernicious means "highly injurious or destructive").
niacin
Definition:a B vitamin needed in energy metabolism. Niacin can be eaten preformed or made in the body from tryptophan, one of the amino acids. Other forms of niacin are nicotinic acid, niacinamide, and nicotinamide.
vit b6
Definition:a B vitamin needed in protein metabolism. Its three active forms are pyridoxine, pyridoxal, and pyridoxamine.
vit b12
Definition:a B vitamin that helps to convert folate to its active form and also helps maintain the sheath around nerve cells. The vitamin's scientific name, not often used, is cyanocobalamin.
macular degeneration
Definition:a common, progressive loss of function of the part of the retina that is most crucial to focused vision. This degeneration often leads to blindness.
dolomite
Definition:a compound of minerals (calcium magnesium carbonate) found in limestone and marble. Dolomite is powdered and is sold as a calcium-magnesium supplement but may be contaminated with toxic minerals, is not well absorbed, and interferes with absorption of other essential minerals.
prooxidant
Definition:a compound that triggers reactions involving oxygen.
Intrinsic factor
Definition:a factor made by the stomach that is necessary for absorption of vitamin B12.
ron-deficiency anemia
Definition:a form of anemia caused by a lack of iron and characterized by red blood cell shrinkage and color loss. Accompanying symptoms are weakness, apathy, headaches, pallor, intolerance to cold, and inability to pay attention. (For other anemias, see the index.)
neural tube defects (NTD)
Definition:a group of abnormalities of the brain and spinal cord apparent at birth and caused by interruption of the normal early development of the neural tube.
IU (international units)
Definition:a measure of fat-soluble vitamin activity sometimes used in food composition tables and on supplement labels.
retinol activity equivalents (RAE)
Definition:a new measure of the vitamin A activity of beta-carotene and other vitamin A precursors that reflects the amount of retinol that the body will derive from a food containing vitamin A precursor compounds.
subclinical deficiency
Definition:a nutrient deficiency that has no outward clinical symptoms. Also called marginal deficiency.
oyster shell
Definition:a product made from the powdered shells of oysters that is sold as a calcium supplement but is not well absorbed by the digestive system.
oxidative stress
Definition:a theory of disease causation involving cell and tissue damage that arises when free radical reactions exceed the capacity of antioxidants to quench them.
dietary folate equivalent, or DFE
Definition:a unit of measure expressing the amount of folate available to the body from naturally occurring sources. The measure mathematically equalizes the difference in absorption between less absorbable food folate (folic acid) and highly absorbable synthetic folate added to enriched foods and found in supplements.
keratinization
Definition:accumulation of keratin in a tissue; a sign of vitamin A deficiency.
antacids
Definition:acid-buffering agents used to counter excess acidity in the stomach. Calcium-containing preparations (such as Tums) contain available calcium. Antacids with aluminum or magnesium hydroxides (such as Rolaids) can accelerate calcium losses.
beta-carotene
Definition:an orange pigment with antioxidant activity; a vitamin A precursor made by plants and stored in human fat tissue.
free radicals
Definition:atoms or molecules with one or more unpaired electrons that make the atom or molecule unstable and highly reactive.
oxidants
Definition:compounds (such as oxygen itself) that oxidize other compounds. Compounds that prevent oxidation are called antioxidants, whereas those that promote it are called prooxidants (anti means "against"; pro means "for").
tannins
Definition:compounds in tea (especially black tea) and coffee that bind iron. Tannins also denature proteins.
precursors
Definition:compounds that serve as starting materials for other compounds. In nutrition, vitamin precursors are compounds that can be converted into active vitamins. Also called provitamins.
dietary antioxidants
Definition:compounds typically found in plant foods that counteract the adverse effects of oxidation on living tissues. The major antioxidant vitamins are vitamin E, vitamin C, and beta-carotene. Many phytochemicals are also antioxidants.
powdered bone
Definition:crushed or ground bone preparations intended to supply calcium to the diet. Calcium from bone is not well absorbed and is often contaminated with toxic materials such as arsenic, mercury, lead, and cadmium.
nonheme iron
Definition:dietary iron not associated with hemoglobin; the iron of plants and other sources.
major minerals
Definition:essential mineral nutrients required in the adult diet in amounts greater than 100 milligrams per day. Also called macrominerals.
Carnitine
Definition:nonessential nutrient that functions in cellular activities.
retinol
Definition:one of the active forms of vitamin A made from beta-carotene in animal and human bodies; an antioxidant nutrient. Other active forms are retinal and retinoic acid.
ascorbic acid
Definition:one of the active forms of vitamin C (the other is dehydroascorbic acid); an antioxidant nutrient.
vitamins
Definition:organic compounds that are vital to life and indispensable to body functions but that are needed only in minute amounts; essential, noncaloric nutrients.
night blindness
Definition:slow recovery of vision after exposure to flashes of bright light at night; an early symptom of vitamin A deficiency.
niacin equivalents (NE)
Definition:the amount of niacin present in food, including the niacin that can theoretically be made from its precursor tryptophan that is present in the food.
Cortical bone
Definition:the ivorylike outer bone layer that forms a shell surrounding trabecular bone and that comprises the shaft of a long bone.
vcalcium compounds
Definition:the simplest forms of purified calcium. They include calcium carbonate, citrate, gluconate, hydroxide, lactate, malate, and phosphate. These supplements vary in the amounts of calcium they contain, so read the labels carefully. A 500-milligram tablet of calcium gluconate may provide only 45 milligrams of calcium, for example.
rickets
Definition:the vitamin D-deficiency disease in children; characterized by abnormal growth of bone and manifested in bowed legs or knock-knees, outward-bowed chest deformity (pigeon chest), and knobs on the ribs.
trabecular bone
Definition:the weblike structure composed of calcium-containing crystals inside a bone's solid outer shell. It provides strength and acts like a calcium storage bank.
Antioxidant nutrients
Definition:vitamins and minerals that oppose the effects of oxidants on human physical functions. The antioxidant vitamins are vitamin E, vitamin C, and beta-carotene. The mineral selenium also participates in antioxidant activities.
hard water
Definition:water with high calcium and magnesium concentrations.
table 7-1b 7-2Characteristics of the Fat-Soluble and Water-Soluble Vitamins Although each vitamin has unique functions and features, a few generalizations about the fat-soluble and water-soluble vitamins can aid understanding.
Fat-Soluble Vitamins: Vitamins A, D, E, and K Water-Soluble Vitamins: B Vitamins and Vitamin C Absorption Absorbed like fats, first into the lymph and then into the blood. Absorbed directly into the blood. Transport and Storage Travel with protein carriers in watery body fluids; stored in the liver or fatty tissues. Travel freely in watery fluids; most are not stored in the body. Excretion Not readily excreted; tend to build up in the tissues. Readily excreted in the urine. Toxicity Toxicities are likely from supplements but occur rarely from food. Toxicities are unlikely but possible with high doses from supplements. Requirements Needed in periodic doses (weekly or even monthly) depending on the extent of body stores. Needed frequently (even daily) because the body does not store most of them to any extent.
As long as B vitamins are present, their presence is not felt. Only when they are missing does their absence manifest itself in a lack of energy and a multitude of other symptoms, as you can imagine after looking at Figure 7-14. The reactions by which B vitamins facilitate energy release take place in every cell, and no cell can do its work without energy. Thus, in a B vitamin deficiency, every cell is affected. Among the symptoms of B vitamin deficiencies are nausea, severe exhaustion, irritability, depression, forgetfulness, loss of appetite and weight, pain in muscles, impairment of the immune response, loss of control of the limbs, abnormal heart action, severe skin problems, swollen red tongue, cracked skin at the corners of the mouth, and teary or bloodshot eyes. Figure 7-15 shows two of these signs. Because cell renewal depends on energy and protein, which, in turn, depend on the B vitamins, the digestive tract and the blood are invariably damaged. In children, full recovery may be impossible. In the case of a thiamin deficiency during growth, permanent brain damage can result.
In academic discussions of the B vitamins, different sets of deficiency symptoms are given for each one. Such clear-cut sets of symptoms are found only in laboratory animals that have been fed fabricated diets that lack just one vitamin. In real life, a deficiency of any one B vitamin seldom shows up by itself because people don't eat nutrients singly; they eat foods that contain mixtures of nutrients. A diet low in one B vitamin is likely low in other nutrients, too. If treatment involves giving wholesome food rather than a single supplement, subtler deficiencies and impairments will be corrected along with the major one. The symptoms of B vitamin deficiencies and toxicities are listed in Table 7-9.
7-4a roles of vit d
Low and borderline blood vitamin D concentrations are not uncommon in the United States. When exposed to sunlight, the skin makes vitamin D. Vitamin D helps regulate blood calcium and modifies genetic activities with far-reaching effects.
Riboflavin DRI Men: 1.3 mg/day Women: 1.1 mg/day Chief Functions Part of coenzyme active in energy metabolism Deficiency Cracks and redness at corners of mouth; painful, smooth, purplish red tongue; sore throat; inflamed eyes and eyelids, sensitivity to light; skin rashes Toxicity None reported
Niacin forms coenzymes important in energy metabolism. Niacin deficiency causes the disease pellagra, which can be prevented by adequate niacin intake or adequate dietary protein. The amino acid tryptophan can be converted to niacin in the body.
exposure to heat and oxidation during extrusion destroys an estimated 30 percent of the vitamin A, 50 percent of the vitamin K, and 90 percent of the vitamin C in the food, with similar losses for almost every other vitamin. Manufacturers may try to compensate by spraying on a few vitamins or minerals, but they cannot replace all of the nutrients, fibers, and phytochemicals lost from the original whole foods. The nutrient density of processed foods exists on a continuum, from farm fresh to ultra-processed. The following are examples of the continuum from lesser to greater degrees of processing: Whole-grain bread > enriched white bread > packaged snack cakes. Milk > fruit-flavored yogurt > "yogurt" covered raisin candy. Fresh spinach > canned spinach > extruded green "vegetable" chips. Baked pork loin > ham lunch meat > fried bacon. An occasional serving of an ultra-processed food is tolerable in nutrition. Just don't use it as a staple food.
One eight-ounce serving of fresh, frozen, or canned orange juice provides most adults' daily need for vitamin C.
Phosphorus Phosphorus is the second most abundant mineral in the body. More than 80 percent of the body's phosphorus is found combined with calcium in the crystals of the bones and teeth. The rest is everywhere else. Roles in the Body All body cells must have phosphorus for these functions: Phosphorous salts are critical buffers, helping to maintain the acid-base balance of cellular fluids. (Note that the mineral is phosphorus. The adjective form is spelled with an -ous, as in phosphorous salts.) Phosphorus is part of the DNA and RNA of every cell and thus is essential for growth and renewal of tissues. Phosphorous compounds carry, store, and release energy during metabolism of energy nutrients. Phosphorous compounds act as cofactors, assisting many enzymes in extracting the energy from nutrients. Phosphorus forms part of the molecules of the phospholipids that are the principal components of cell membranes (discussed in Chapter 5). Phosphorus is present in some proteins.
Phosphorus DRI Adults: 700 mg/day Tolerable Upper Intake Level Adults (19-70 yr): 4,000 mg/day Chief Functions Mineralization of bones and teeth; part of phospholipids, important in genetic material, energy metabolism, and buffering systems Deficiency Muscular weakness, bone pain Toxicity Calcification of soft tissues, particularly the kidneys
Zinc Zinc occurs in a very small quantity in the human body, but it occurs in every organ and tissue. It acts as a cofactor for more than 300 enzymes to: Protect cell structures against damage from oxidation. Make parts of the cells' genetic material. Make the heme of hemoglobin. Zinc also assists the pancreas with its digestive and insulin functions and helps metabolize carbohydrate, protein, and fat. Besides helping enzymes to function, special zinc-containing proteins associate with DNA and help regulate protein synthesis and cell division, functions critical to normal growth before and after birth. Zinc is also needed to produce the active form of vitamin A in visual pigments. Even a mild zinc deficiency can impair night vision. Zinc also: Affects behavior, learning, and mood. Assists in proper immune functioning. Is essential to wound healing, sperm production, taste perception, normal metabolic rate, nerve and brain functioning, bone growth, normal development in children, and many other functions. When zinc deficiency occurs—even a slight deficiency—it packs a wallop to the body, impairing all of these functions.
Problem: Too Little Zinc Zinc deficiency in human beings was first observed a half-century ago in children and adolescent boys in the Middle East who failed to grow and develop normally (see Figure 8-18). Their native diets were typically low in animal protein and high in whole grains and beans; consequently, the diets were low in zinc and high in fiber and phytates, which bind zinc as well as iron. Furthermore, their bread was not leavened. (In leavened bread, yeast breaks down phytates as the bread rises.) Since that time, zinc deficiency has been identified as a substantial contributor to illness throughout the developing world and is known to be responsible for almost a half-million deaths each year.
The DRI Tolerable Upper Intake Level (UL) for vitamin C is set at 2,000 mg (2 g)/day. Only 10 mg/day prevents scurvy.
The adult DRI for vitamin C is 90 milligrams for men and 75 milligrams for women. These amounts are far higher than the 10 or so milligrams per day needed to prevent the symptoms of scurvy. In fact, they are close to the amount at which the body's pool of vitamin C is full to overflowing: about 100 milligrams per day.
fat solu
The fat-soluble vitamins are absorbed similarly to fat absorption. d. They are not readily excreted and tend to build up in tissues. They are stored in the liver and fatty tissues.
Other colorful vegetables, such as red beets, red cabbage, and yellow corn, can fool you into thinking they contain beta-carotene, but these foods derive their colors from other pigments and are poor sources of beta-carotene.
The vitamin A precursor in plants, beta-carotene, is an effective antioxidant in the body. Many brightly colored plant foods are rich in beta-carotene.
Snapshot 7-6 Thiamin DRI Men: 1.2 mg/day Women: 1.1 mg/day Chief Functions Part of coenzyme active in energy metabolism DeficiencyFootnote Beriberi with possible edema or muscle wasting; enlarged heart, heart failure, muscular weakness, pain, apathy, poor short-term memory, confusion, irritability, difficulty walking, paralysis, jerky eye movements, anorexia, weight loss Toxicity None reported Good Sources
Thiamin is a coenzyme important in energy metabolism and in nerve cell processes. The thiamin deficiency disease is beriberi. Many foods supply small amounts of thiamin.
7-3 vitamin A
Vitamin A has the distinction of being the first fat-soluble vitamin to be recognized. Today, after a century of scientific investigation, vitamin A and its plant-derived precursor, beta-carotene, are still very much a focus of research. Three forms of vitamin A are active in the body. One of the active forms, retinol, is stored in specialized cells of the liver. The liver makes retinol available to the bloodstream and thereby to the body's cells. The cells convert retinol to its other two active forms, retinal and retinoic acid, as needed. Foods derived from animals provide forms of vitamin A that are readily absorbed and put to use by the body. Foods derived from plants provide beta-carotene, which must be converted to active vitamin A before it can be used.
Which statement is true of vitamin C?
Vitamin C acts as an antioxidant.
Intake recommendations for smokers are set high, at 125 milligrams for men and 110 milligrams for women, in order to maintain blood concentrations comparable to those of nonsmokers. Importantly, vitamin C ca
Vitamin C maintains collagen, protects against infection, acts as an antioxidant, and aids iron absorption. Ample vitamin C can be easily obtained from foods.
Folate is part of a coenzyme necessary for making new cells. Low intakes of folate cause anemia, digestive problems, and birth defects in infants of folate-deficient mothers. High intakes can mask the blood symptom of a vitamin deficiency.
Vitamin is critical for cell replication and proper nerve functioning. Vitamin occurs only in foods of animal origin. Vitamin -deficiency anemia mimics folate deficiency and arises with low intakes or, more often, poor absorption. Folate supplements can mask a vitamin deficiency
all tru
Vitamins A, D, E, and K are fat-soluble. b. Fat-soluble vitamins require bile to be absorbed in the body. c. Fat-soluble vitamins are stored, and therefore overconsumption may lead to toxicity.
7-1b keypoints
Vitamins are essential, noncaloric nutrients that are needed in tiny amounts in the diet and are indispensable for normal cellular processes. Vitamin precursors in foods are transformed into active vitamins by the body. The fat-soluble vitamins are vitamins A, D, E, and K. The water-soluble vitamins are vitamin C and the B vitamins.
Wernicke-Korsakoff syndrome
a cluster of symptoms involving nerve damage arising from a deficiency of the vitamin thiamin in alcoholism. Characterized by mental confusion, disorientation, memory loss, jerky eye movements, and staggering gait.
inositol
a nonessential nutrient found in cell membranes
hyponatremia
an abnormally low concentration of sodium in the blood.
water sol vitamins
b. Foods that supply the water-soluble vitamins must be consumed frequently. c. Easily lost or destroyed in food preparation and processing. d. Easily absorbed and excreted from the body
All of the following are good food sources of vitamin D EXCEPT:
citrus fruits.
All of the following are functions of vitamin C
collagen synthesis b. antioxidant oosting iron absorption
Vitamin E is famous for its role.
in protecting tissues from oxidation
Current recommendations for fruit and vegetable intakes are for us to consume a variety from each category on a daily basis. What are the two vitamins that are abundant in leafy greens and citrus fruits, as well as other fruits and vegetables?
folate and vitamin C
7-3a roles of vitamin A and consequences of deficiency, and sources of vitmain a
gene expression, vision, maintenance of body linings and skin, immune defenses, growth of the body, and normal development of cells.male and female reproductive functions and for normal development of an embryo and fetus. dri tolerable upper intake and func, deficienct, toxicity
Definition:(FYE-tates) compounds present in plant foods (particularly whole grains) that bind iron and may prevent its absorption.
phytates
The need for vitamin E rises as people consume more of what because it requires antioxidant protection by the vitamin?
polyunsaturated fat
xerophthalmia
progressive hardening of the cornea of the eye in advanced vitamin A deficiency that can lead to blindness (xero means "dry"; ophthalm means "eye").
Vitamin Names Fat-Soluble Vitamins Vitamin A Vitamin D Vitamin E Vitamin K Water-Soluble Vitamins B vitamins Thiamin Riboflavin Niacin Folate Vitamin Vitamin Biotin Pantothenic acid Vitamin C
table 7-1
Deficiency in the water-soluble vitamins, B12 and folate, contribute to anemia and a deficiency in niacin causes pellagra.
tru
Folate supplements can mask a B12 deficiency
tru
amino acid chelates
vDefinition:(KEY-lates) compounds of minerals (such as calcium) combined with amino acids in a form that favors their absorption. A chelating agent is a molecule that attracts or embraces another molecule and can then either promote or prevent its movement from place to place (chele means "claw").
vitamin e
veg oil