Vitamin B12

        

                            U.S. Recommended Daily Allowances

         Infants        Children      Adults and           Pregnant or

         (0-12 mo.)     (1-3 years)   Children 4 Years +   Nursing Women

         2 micrograms   3 mcg         6 mcg                8 mcg

               (The U.S. RDA amounts are sufficient to meet the needs

          of practically all healthy people.)

               Vitamin B12 (cobalamin) is a water-soluble vitamin

          whose primary sources are animal products; plant foods are

          virtually devoid of it.

               Functions: Aids in red blood cell development and the

          functioning of all cells, particularly those of the bone

          marrow, nervous system, and intestines. Also helps

          metabolize protein and fat in the body.

               Sources: Animal products, including liver and other

          organ meats, beef, pork, eggs, milk and milk products, and

          fish. Bacteria in the intestinal tract produce some vitamin

          [B.sub.12] and thus may serve as another source.

               Deficiency: Signs include weakness, sore tongue, and

          anemia. It also is linked to some nerve and psychiatric

          disorders. However, vitamin [B.sub.12] deficiency is rare,

          and more than 95 percent of cases seen in the United States

          are related to the body's inability to absorb the vitamin.

               Excess: No toxicity has been reported from high

          intakes, but no benefits have been reported, either.

Niacin

          

         

        

         

         

                            U.S. Recommended Daily Allowances

         

          Infants      Children      Adults and           Pregnant or

         

          (0-12 mo.)   (1-3 years)   Children 4 Years +   Nursiing Women

         

          8 mg         9 mg          20 mg                20 mg

         

              (The U.S. RDA amounts are sufficient to meet the needs

          of practically all healthy people.)

          

               Niacin (nicotinic acid, nicotinamide) is a

          water-soluble vitamin whose requirement is partly met by

          conversion in the body of the essential amino acid

          tryptophan to niacin.

         

               Functions: Involved in carbohydrate, protein and fat

          metabolism.

         

               Sources: Enriched cereal-grain products; meat, fish,

          poultry, cheese, eggs, and milk because they contain

          tryptophan; peanuts; mushrooms; potatoes.

         

               Deficiency: Severe niacin deficiency causes pellagra,

          a disease characterized by mouth sores, skin rashes,

          diarrhea, and dementia.  Deficiency is rarely seen in the

          United States, though, because most people have adequate

          intakes.

         

               Excess: Large amounts of niacin, when taken in the

          nicotinic acid form of the vitamin, act as a drug.

          Nicotinic acid is often prescribed as a

          cholesterol-lowering drug, and should be taken only under

          the supervision of a physician. Side effects include

          vascular dilation of the skin (flushing) and

          gastrointestinal distress. Prolonged intake may cause liver

          damage.

         

               Nicotinamide is not known to act as a drug. Effects of

          high doses are unknown.

          

Vitamin B2

          

               U.S. Recommended Daily Allowances

               Infants (0-12 mo.): 0.6 mg

               Children (1-3 years): 0.8 mg

               Adults and Children 4 Years +: 1.7 mg

               Pregnant or or Nursing Women:  2.0 mg

               (The U.S. RDA amounts are sufficient to meet the needs

          of practically all healthy people.)

               Riboflavin (vitamin B2) is a water-soluble vitamin

          that plays a role in energy production.

               Functions: Component of two coenzymes that help

          convert carbohydrates and protein to energy.

               Sources: Meat, poultry and fish; milk and cheese;

          enriched cereal-grain products; green vegetables, such as

          broccoli, turnip greens, asparagus, and spinach; eggs.

               Deficiency: Signs of deficiency include cracks and

          sores on the lips and at the comers of the mouth, skin

          rash, and dimness of vision.  Deficiency is rare in the

          United States because most people have adequate intakes.

               Excess: High doses appear nontoxic.

Vitamin B1

      

                U.S. Recommended Daily Allowances

         Infants     Children        Adults and           Pregnant or

         (0-12 mo.)  (1-3 years)     Children 4 Years +   Nursing Women

         0.5 mg       0.7 mg             1.5 mg                 1.7 mg

               (The U.S. RDA amounts are sufficient to meet the needs

          of practically all healthy people.)

               Thiamin (vitamin B1) is a water-soluble vitamin that

          was the first identified member of the TB complex group.

               Functions: Helps convert carbohydrates to energy; aids

          in nerve cell functioning.

               Sources: Brewer's yeast; lean cuts of pork;

          whole-grain or enriched cereal grain products; legumes;

          liver, heart and kidneys; nuts and seeds.

               Deficiency: Thiamin deficiency causes beriberi, a

          disease whose symptoms include anorexia, weakness, lack of

          coordination, muscle wasting, paralysis of the eye muscles,

          mental confusion, rapid heartbeat, edema, and enlarged

          heart. Deficiency is sometimes seen in this country in

          people with alcoholism and certain medical conditions.

              Excess: High intakes appear nontoxic since excess

          thiamin is easily excreted by the kidneys.

Vitamin C

          

               Vitamin C (ascorbic acid) is a water-soluble vitamin

          found in a variety of fruits and vegetables that is easily

          destroyed when exposed to air, heat and light.

         

               Functions: Essential for growth and maintenance of all

          cells and tissues; promotes the absorption of iron in the

          intestines; and acts as a water-soluble antioxidant in the

          body.

         

               Sources: Many fruits and vegetables, including citrus

          fruits, cantaloupe, strawberries, tomatoes, green and red

          peppers, kale, collards, mustard greens, broccoli, cabbage,

          and potatoes.

         

               Deficiency: Signs of deficiency include delayed wound

          healing; increased susceptibility to infection; and scurvy,

          a condition characterized by bleeding under the skin,

          anemia, joint tenderness and swelling, poor wound healing,

          weakness, and such oral disorders as bleeding gums, tooth

          loss, and gingivitis. However, because vitamin C sources

          are plentiful in the U.S. food supply, deficiency is rarely

          seen; it mainly occurs n infants fed cow's milk only, or in

          people whose diets lack adequate sources of vitamin C. In

          addition, cigarette smokers have lower blood levels of

          vitamin C than nonsmokers. As a consequence, the National

          Research Council recommends that smokers consume at least

          100 milligrams of vitamin C per day.

         

               Excess: High intakes of 1 gram or more per day may

          cause nausea, abdominal cramps, and diarrhea in some

          people.

         

          

VITAMIN K

          

            

         

              Vitamin K is a fat-soluble vitamin usually formed in

          the body by intestinal bacteria but also available from

          some plant and animal sources.

         

              Function: Essential in the formation of prothrombin, a

          substance necessary for proper clotting of blood, and at

          least five other blood-clotting factors.

         

              Sources: All green leafy vegetables (including lettuce,

          spinach, kale, and cabbage), eggs, meats, cereal grain

          products, fruits, and milk and dairy products.

         

              Deficiency: vitamin K deficiency may cause bleeding

          disorders in premature infants with inadequate amounts of

          stored vitamin K, and in people on blood-thinning

          medications and those with fat malabsorption syndromes.

         

              Excess: Natural forms have no known toxic effects;

          large doses of the synthetic version, menadione, and its

          derivatives cause anemia and kernicterus, a condition

          characterized by jaundice, in infants.

         

          

Vitamin E

          

               Vitamin E is a fat soluble vitamin not recognized as

          an essential nutrient until the 1960s, about 40 years after

          its discovery.

         

               Function: Prevents potentially harmful oxidation of

          polyunsaturated fatty acids in the body, which would lead

          to cell damage; important in protecting red blood cell

          membranes from oxidation.

         

               Sources: Nuts; vegetable oils; fortified ready-to-eat

          cereals; wheat germ; green leafy vegetables; margarines

          made from vegetable oils; shrimp and other seafood

          (including clams, salmon and scallops); some fruits, such

          as apples, apricots and peaches.

          

               Deficiency: Vitamin E deficiency can cause anemia, as

          a result of red blood cell destruction, and nerve damage.

          However, deficiency is rare and mainly occurs in premature,

          verylow-birth-weight infants and people with fat absorption

          disorders, such as cystic fibrosis.

         

               Excess: Some evidence suggests that large intakes may

          cause increased levels of blood cholesterol and lipids.

         

               U.S. Recommended Daily Allowances

         

           Infants      Children     Adults and          Pregnant or

         

           (0-12 mo.)   (1-3 years)  Children 4 Years+   Nursing Women

         

            5IU*        10 IU        30 IU               30 IU

         

                                             * International units

         

               (The U.S. RDA amounts are sufficient to meet the needs

          of practically all healthy people.)

         

          

VITAMIN D

          

               

         

               Vitamin D is a fat-soluble vitamin available from some

          foods, as well as from sunlight.

         

               Functions: Forms the hormone 1,

          25-dihydrocholecalciferol, which aids in the absorption and

          metabolism of calcium and phosphorus for bone and tooth

          formation.

         

               Sources: Sunlight (which stimulates vitamin D

          production in the skin), fatty fish, fish liver oils,

          vitamin D-fortified milk, egg yolk, and butter.

         

               Deficiency: In children, vitamin D deficiency causes

          rickets, a disease in which weak bones lead to bowlegs,

          knock-knees, and other bone deformities. The disease is

          rarely seen in the United States because milk and other

          foods are fortified with vitamin D and because children

          usually get some sun exposure. In the elderly, especially

          those in extended-care facilities, vitamin D deficiency has

          been associated with calcium loss from bones.

         

               Excess: High intakes may cause vomiting, diarrhea, and

          weight loss and lead to calcium deposits in various organs.

          Children are especially susceptible, but anyone can have

          adverse effects from high daily doses.

         

          

Pantothenic acid

          

         

               Pantothenic acid is a B-complex vitamin.

         

               Functions: Involved in release of energy from

          carbohydrates, metabolism of fats, and synthesis of steroid

          hormones and other vital substances.

         

               Sources: Milk; beef, pork and poultry; legumes; some

          fruits and vegetables, including strawberries, dried fruit,

          avocados, mushrooms, potatoes, and succotash; whole-grain

          cereal products.  Deficiency: Pantothenic acid deficiency

               has not been recognized in humans, and it is unlikely

          to occur in the U.S. population.

         

               Excess: No effects have been reported.

          

Biotin

          

         

          

         

               U.S. Recommended Daily Allowances

         

             Infants      Children    Adults and           Pregnant or

         

            (0-12 mo.)    (1-3 years) Children 4 Years +  Nursing Women

         

            50 micrograms 150 mcg     300 mcg               300 mcg

         

               (The U.S. RDA amounts are sufficient to meet the needs

          of practically all healthy people. FDA set these based on

          the 1968 Recommended Dietary Allowances by the National

          Research Council of the National Academy of Sciences.

          However, in 1989, the council lowered its ranges of safe

          and adequate daily dietary intakes for biotin to 10 to 15

          micrograms for infants, 20 to 30 mcg for children, and 30

          to 100 mcg for adults. FDA is in the process of revising

          its U.S. RDAs.)

         

               Biotin is a sulfur-containing, B-complex vitamin found

          in foods and produced by microorganisms in the lower

          gastrointestinal tract.

         

               Functions: Activates certain enzymes that aid in

          metabolism of carbon dioxide; involved in metabolism of

          protein, fats and carbohydrates.

         

               Sources: Widely distributed in foods that are sources

          of B vitamins, including cereal-grain products, liver, egg

          yolk, soy flour, and yeast.

         

               Deficiency: Signs include loss of appetite, nausea,

          vomitting, inflammation of the tongue, pallor, depression,

          hair loss, and dry, scaly skin. Some rare biotin-related

          inborn errors of metabolism may cause deficiency;

          otherwise, deficiency is extremely rare in the United

          States.

         

               Excess: No effects have been reported.

          

Vitamin B6

               Vitamin B6 is a water-soluble vitamin that

          comprises three related forms: pryidoxine, pryidoxal and

          pryidoxamine.

               Function: Plays many roles in the body, the but most

          important one is in protein metabolism.

               Sources: Fortified instant oatmeal; fortified

          ready-to-eat cereals; meat, poultry and fish; soybeans;

          some fruits and vegetables, including bananas, prunes,

          watermelon, spinach, sweet potatoes, and tomato juice.

               Deficiency: Vitamin B6 deficiency can cause anemia,

          dermatitis and convulsions. In infants, it can lead to a

          variety of neurological disorders and abdominal distress.

          Deficiency is rare in the United States; it is mainly seen

          in people deficient in several B-complex vitamins.

               Excess: Long-term megadoses, such as may be taken by

          women to alleviate premenstrual syndrome, may cause nerve

          damage and muscular incoordination in the hands and feet.

               U.S. Recommended Daily Allowances

        Infants      Children      Adults and           Pregnant or

        (0-12 mo.)   (1-3 years)   Children 4 Years +   Nursing Women

         0.4 mg       0.7 mg        2.0 mg               2.5 mg

               (The U.S. RDA amounts are sufficient to meet the needs

              of practic all healthy people.)

VITAMIN A

Vitamin A (retinoid) is a fat-soluble vitamin found

mainly in animal foods in the vitamin form and in plant

foods primarily as carotenes, substances that are formed

into vitamin A chiefly in the small intestine.

Function: Essential for growth and for keeping skin

and other tissues healthy; helps eyes to adapt to dim light

and perceive colors; essential for normal tooth

development.

Sources: Beef, chicken and pork livers; whole and

vitamin A-fortified milk; cheddar cheese; butter;

margarine; egg yolk; deep green, yellow or orange

vegetables and fruits (including carrots, spinach,

collards, broccoli, kale, nectarines, apricots, mangoes,

cantaloupe, pumpkins, winter squash, turnip greens, sweet

potatoes, and watermelon).

Deficiency: Vitamin A deficiency is reare in the

United States; it mainly occurs among some people in

developing countries. Some signs include skin changes,

stunted growth, night blindness, and serious eye problems

(such as drying, thickening, wrinkling, and muddy

pigmentation of the mucous membrane lining the eyelid and

eyeball, which eventually can destroy the eye). Inadequate

intakes of foods containing vitamin A have been associated

with some types of cancer, but the effect, if any, appears

related to lack of carotene.

Excess: Because vitamin A is fat soluble, it is stored

in the body. As a result, continued high doses (several

times the U.S. RDA) have toxic effects. Signs of toxicity

include dry and itching skin, headaches, and nausea and

diarrhea. High vitamin A intake during pregnancy also may

cause birth defects, but it is not known at what level this

can occur. Excessive amounts of carotene are not known to

be toxic, but will cause the skin to turn deep yellow. The

color disappears when the amount of carotene in the diet is

decreased.