NF 25 Chapter 7
Characteristics of water-soluble vitamins
-absorbed directly into the blood -travel freely in watery fluids; most are not stored in the body -excess excreted in the urine - Toxicities are unlikely but possible with high dosages from supplements - Needed in frequent doses (perhaps 1 - 3 days) because the body does not store most of them to any extent
Vitamin A is a versatile vitamin, with roles in:
1. gene expression 2. vision 3. maintenance of body linings and skin 4. immune defenses 5. growth of the body 6. and normal development of cells.
The vitamin K requirement for men is _________ micrograms a day
120
The DRI recommended intake for vitamin E is _________ milligrams a day for adults.
15 mg
As for vitamin A supplements, the DRI committee warns against exceeding the Tolerable Upper Intake Level of ____________ micrograms (for adults older than age 18)
3,000
An ounce of ordinary beef or pork liver delivers three times the DRI recommendation for vitamin A intake, and a common portion is ___________ ounces
4 to 6
The adult DRI intake recommendation for vitamin C is _______ milligrams for women.
75 mg
The vitamin K requirement for women is ___________ micrograms a day
90
The adult DRI intake recommendation for vitamin C is _____ milligrams for men
90 mg
A typical man needs a daily average of about _______ micrograms of active vitamin A; a typical woman, who weighs less, needs about _________ micrograms.
900; 700
ascorbic acid
- one of the active forms of vitamin C (the other is dehydroascorbic acid); an antioxidant nutrient. - literally means "no-scurvy acid."
Chief Functions of vitamin D
Mineralization of bones and teeth (raises blood calcium and phosphorus by increasing absorption from digestive tract, withdrawing calcium from bones, stimulating retention by kidneys)
free radicals
atoms or molecules with one or more unpaired electrons that make the atom or molecule unstable and highly reactive.
an orange pigment with antioxidant activity; a vitamin A precursor made by plants and stored in human fat tissue.
beta-carotene
One of the symptoms of vitamin D toxicity is elevated _______________________.
blood calcium
White blood cells that fight diseases equally depend on vitamin E's antioxidant nature, as do ________________, ________________, and _______________.
blood vessel linings, sensitive brain tissues, and even bones
Vitamin K is also necessary for the synthesis of key ___________ proteins. With low blood vitamin K, the bones produce an abnormal protein that cannot effectively bind the minerals that normally form bones
bone
The main function of vitamin K†† is to help activate proteins that help ___________ the blood.
clot
The enzymes involved in the formation and maintenance of the protein ________________ depend on vitamin C for their activity
collagen
Vitamin C performs a variety of functions in the body. It is best known for two of them: its work in maintaining the ______________ and as an antioxidant.
connective tissues
vitamin K's richest plant food sources include _________________ such as cooked spinach and other greens, which provide an average of 300 micrograms per half-cup serving.
dark green, leafy vegetables
The disease scurvy is seldom seen today except in a few __________________, people addicted to alcohol or other drugs, sick people in hospitals, and a few infants who are fed only cow's milk.
elderly people
vitamin K toxicity can result when supplements of a synthetic version of vitamin K are given too __________________.
enthusiastically
A classic vitamin E deficiency occurs in premature babies born before the transfer of the vitamin from the mother to the fetus, which takes place late in pregnancy. Without sufficient vitamin E, the infant's red blood cells rupture (_______________________), and the infant becomes anemic.
erythrocyte hemolysis
Vitamin A Vitamin D Vitamin E Vitamin K
fat soluble vitamins
Water-soluble vitamins are easily absorbed and excreted from the body, and foods that supply them must be consumed ____________.
frequently
Disease or injury of the liver (which makes bile, necessary for digestion of fat), the _____________ (which delivers bile into the intestine), or the pancreas (which makes fat-digesting enzymes) makes vitamin E deficiency likely.
gallbladder
confer
grant or bestow (a title, degree, benefit, or right).
One symptom of vitamin D deficiency is ______________.
headache
Vitamin E is readily destroyed by ___________________—thus, fresh, raw oils and lightly processed vitamin E-rich foods are the best sources.
heat and oxidation
The few symptoms of vitamin E deficiency observed in adults include loss of muscle coordination and reflexes and ________________ and speech. Vitamin E corrects all of these symptoms.
impaired vision
Few U.S. adults are likely to experience vitamin K deficiency, even if they seldom eat vitamin K-rich foods. This is because, like vitamin D, vitamin K can be obtained from a nonfood source—in this case, the ____________________.
intestinal bacteria
In the intestines, vitamin C protects _____________ from oxidation and so promotes its absorption
iron
A toxic dose of synthetic vitamin K causes the _________ to release the blood cell pigment (bilirubin) into the blood (instead of excreting it into the bile) and leads to jaundice.
liver
Disease or injury of the __________ (which makes bile, necessary for digestion of fat), the gallbladder (which delivers bile into the intestine), or the pancreas (which makes fat-digesting enzymes) makes vitamin E deficiency likely.
liver
Foods naturally rich in vitamin A pose little risk of toxicity, with the possible exception of ___________.
liver
Active vitamin A is present in foods of animal origin. The richest sources are _____ and ______, but milk and milk products and other vitamin A-fortified foods such as enriched cereals can also be good sources.
liver and fish oil
Water-soluble vitamins are easily ___________ or ___________ during food preparation and processing.
lost or destroyed
The antioxidant protection of vitamin E is crucial, particularly in the ____________, where high oxygen concentrations would otherwise disrupt vulnerable membranes.
lungs
The few symptoms of vitamin E deficiency observed in adults include loss of ______________ and reflexes and impaired vision and speech. Vitamin E corrects all of these symptoms.
muscle coordination
One symptom of vitamin D toxicity is _______________
nausea
If the vitamin A supply begins to run low, a lag occurs before the eye can see again after a flash of bright light at night. This lag in the recovery of night vision is termed ____________________.
night blindness
____________________ supplements are useless against heart disease, cancer, and other diseases unless they are prescribed to treat a deficiency
oral vitamin c
Vitamin C protects substances found in foods and in the body from _____________ by being oxidized itself.
oxidation
Disease or injury of the liver (which makes bile, necessary for digestion of fat), the gallbladder (which delivers bile into the intestine), or the ______________ (which makes fat-digesting enzymes) makes vitamin E deficiency likely.
pancreas
Compounds that can be converted into active vitamins. Also called provitamins
precursors
Reports of vitamin K toxicity among healthy adults are ________
rare
Vitamin E in foods is safe to consume, and reports of vitamin E toxicity symptoms are _____________ across a broad range of intakes.
rare
The few symptoms of vitamin E deficiency observed in adults include loss of muscle coordination and _______________ and impaired vision and speech. Vitamin E corrects all of these symptoms.
reflexes
Hundreds of genes are regulated by the _______________ form of vitamin A. Genes direct the synthesis of proteins, including enzymes that perform the metabolic work of the tissues. Hence, through its influence on gene expression, vitamin A affects the metabolic activities of a vast array of tissues and, in turn, the health of the body.
retinoic acid
Three forms of Vitamin A are active in the body. One of the active forms, _______________, is stored in specialized cells of the liver.
retinol
Three forms of vitamin A are active in the body. One of the active forms, ____________, is stored in specialized cells of the liver
retinol
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
retinol
When light falls on the eye, it passes through the clear cornea and strikes the cells of the retina, bleaching many molecules of the pigment __________ that lie within those cells. Vitamin A is a part of the ___________ molecule.
rhodopsin
erythrocyte (eh-REETH-ro-sight) hemolysis (HEE-moh-LIE-sis, heeMOLL-ih-sis)
rupture of the red blood cells that can be caused by vitamin E deficiency (erythro means "red"; cyte means "cell"; hemo means "blood"; lysis means "breaking"). The anemia produced by the condition is hemolytic (HEE-moh-LIT-ick) anemia.
The ______________ range of vitamin C intakes seems to be broad, from the absolute minimum of 10 milligrams a day to the Tolerable Upper Intake Level of 2,000 milligrams (2 grams)
safe
The disease ____________ is seldom seen today except in a few elderly people, people addicted to alcohol or other drugs, sick people in hospitals, and a few infants who are fed only cow's milk
scurvy
One symtom of vitamin D toxicity is calcification of _______________.
soft tissues (blood vessels, kidneys, heart, lungs, tissues of joints)
The few symptoms of vitamin E deficiency observed in adults include loss of muscle coordination and reflexes and impaired vision and __________. Vitamin E corrects all of these symptoms.
speech
Newborn infants present a unique case with regard to vitamin K because they are born with a _______________ and the vitamin K-producing bacteria take weeks to establish themselves. To prevent hemorrhage, the newborn is given a single dose of vitamin K at birth.
sterile intestinal tract
On average, U.S. intakes of vitamin E fall ___________ the recommendation
substantially below
vitamin K toxicity can result when supplements of a _____________version of vitamin K are given too enthusiastically
synthetic
osteomalacia
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.
collagen
the chief protein of most connective tissues, including scars, ligaments, and tendons, and the underlying matrix on which bones and teeth are built.
scurvy
the vitamin C-deficiency disease.
rickets
the vitamin D-deficiency disease in children; characterized by abnormal growth of bone and manifested in bowed legs or knock-knees, outward-bowed chest, and knobs on the ribs.
One symptom of vitamin D toxicity is excessive __________________.
thirst
The vitamin A precursor beta-carotene is naturally present in many ______________________.
vegetable and fruit varieties
Much of the vitamin E that people consume comes from ___________________ and products made from them
vegetable oils
Foods derived from animals provide forms of ______________ that are readily absorbed and put to use by the body. Foods derived from plants provide beta-carotene, which must be converted to active _________________ before it can be used as such.
vitamin A
Much research supports the need for ______________ in the regulation of the genes involved in immunity. Without sufficient _______________, these genetic interactions produce an altered response to infection that weakens the body's defenses.
vitamin A
The water-soluble vitamins are _____________________________
vitamin C and the B vitamins
In people without diseases, low blood levels of ____________ are most likely when diets extremely low in fat are consumed for years.
vitamin E
Red blood cell membranes also need ______________ protection as they transport oxygen from the lungs to other tissues.
vitamin E's
White blood cells that fight diseases equally depend on ______________ antioxidant nature, as do blood vessel linings, sensitive brain tissues, and even bones.
vitamin E's
For _____________________ vitamins, most are not stored in tissues to any great extent; rather, excesses are excreted in the urine. Thus, the risks of immediate toxicities are not as great as for fat-soluble vitamins.
water-soluble
The ______________________ vitamins are absorbed directly into the bloodstream, where they travel freely.
water-soluble
One symptom of vitamin D toxicity is ___________________.
weakness
DRI Recommended Intakes for vitamin D
Adults: 15 μg (600 IU)/day (19-70 yr) 20 μg (700 IU)/day (> 70 yr)
Characteristics of Fat-Soluble Vitamins
-absorbed like fats, first into the lymph and then into the blood -must travel with protein carriers in watery body fluids; stored in the liver or fatty tissues -Not readily excreted; tend to build up in the tissues -Toxicities are likely from supplements but occur rarely from food -Needed in periodic doses (perhaps week or even months) because the body an draw on its stores
The fat-soluble vitamins are vitamins _______________________.
A, D, E, and K
Deficiency symptoms of vitamin D
Abnormal bone growth resulting in rickets in children, osteomalacia in adults; malformed teeth; muscle spasms
Toxicity of vitamin D
Elevated blood calcium; calcification of soft tissues (blood vessels, kidneys, heart, lungs, tissues of joints), excessive thirst, headache, nausea, weakness
____________ vitamins can be stored in the liver or with other lipids in fatty tissues, and some can build up to toxic concentrations.
Fat-soluble
B vitamins: Thiamin (B1), Riboflavin (B2), Niacin (B3), Folate (B9), Vitamin B12, Vitamin B6, Biotin (B7), Pantothenic acid (B5), & Vitamin C
Water-soluble Vitamins
_____________ is essential for normal reproductive processes. In men, _______________ participates in sperm development, and in women, it supports normal fetal development during pregnancy. In the developing embryo, ___________________ is crucial for the formation of the spinal cord, heart, and other organs.
Vitamin A
______________ is also indispensable for growth in children. Normal children's bones grow longer, and the children grow taller, by remodeling each old bone into a new, bigger version.
Vitamin A
_____________________ is needed by all epithelial tissue (external skin and internal linings). The cornea of the eye, already mentioned, is such a tissue; so are skin and all of the protective linings of the lungs, intestines, vagina, urinary tract, and bladder. These tissues serve as barriers to infection and other threats.
Vitamin A
_____________ is listed among the nutrients of national concern because U.S. intakes may fall short of the DRI recommendations. Especially people who smoke or have low incomes are at risk for deficiency.
Vitamin C
_____________________ flows throughout the body, guarding the tissues against harm from destructive oxidative reactions.
Vitamin E
___________________ is necessary for blood to clot and for bone health. Each is worth a book in itself.
Vitamin K
______________ are essential, noncaloric nutrients that are needed in tiny amounts in the diet and help to drive cellular processes.
Vitamins
organic compounds that are vital to life and indispensable to body functions but that are needed only in minute amounts; essential, noncaloric nutrients.
Vitamins
_______________________ act somewhat like hormones, directing cells to convert one substance to another, to store this, or to release that. They also directly influence the genes, thereby regulating protein production.
Vitamins A and D
tocopherol (tuh-KOFF-er-all)
a kind of alcohol. The active form of vitamin E is alpha-tocopherol.
IU (international units)
a measure of fatsoluble vitamin activity sometimes used in food composition tables and on supplement labels.
retinol activity equivalents (RAE)
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
Vitamin precursors in foods are transformed into _______________ by the body.
active vitamins
People who have taken _________ that have killed the bacteria in their intestinal tracts also may develop vitamin K deficiency.
antibiotics
Vitamin C performs a variety of functions in the body. It is best known for two of them: its work in maintaining the connective tissues and as an _________________.
antioxidant