HSR'S ANNUAL GUIDE TO VITAMINS

Vitamin B

Although the water-soluble B vitamins each have their own unique, individual properties, they possess similar coenzyme functions and are commonly found together in foods. They are very important for the normal functioning of the nervous system and are often helpful in bringing relaxation or energy to individuals who are stressed or fatigued. Additionally, B vitamins help provide energy by acting with enzymes to convert carbohydrates to glucose and also are important in fat and protein/ amino acid metabolism. These nutrients also influence the health of skin, hair, eyes and liver.

However, because the B vitamins are not easily digested and absorbed, deficiencies of one or more B vitamin is not uncommon, particularly during times of fasting or dieting. Because of these deficiencies and no known toxicity associated with their use, modest excesses should not be cause for concern. When the amount of B vitamins taken exceeds the body's needs, the excess is easily excreted in the urine.

Vitamin B1

Vitamin B1, also known as thiamin, was the first of the B vitamins to be discovered and is essential for nearly every cellular reaction in the body. This is due to its involvement in energy production and carbohydrates.

Thiamin is important in the health of the nervous system because of its role in the synthesis of the neurotransmitter acetylocholine. This vitamin also helps prevent the accumulation of fatty deposits in arteries which helps prevent the progression of atherosclerosis.

Thiamin-rich foods include organ meats, dried beans, peas, soybeans, peanuts, poultry, egg yolks and fish. Other sources include plums, raisins, asparagus, broccoli and oatmeal. Cooking destroys some thiamin in food, as does exposure to ultra-violet light, sulfates, nitrites and live yeast.

Thiamin deficiency is rare in developed countries, because most flours and cereal are fortified with the vitamin. However, there is a risk of deficiency for young children, teenagers, stressed adults, heavy exercisers, alcoholics and pregnant women. The most common deficiency is called beriberi and it affects the gastrointestinal, cardiovascular and peripheral nervous systems. Symptoms include loss of stamina, depression, irritability, reduced ability to concentrate, fatigue, muscle cramps, indigestion, constipation, insomnia, heaviness in the legs and various other pains.

The Recommended Daily Intake (RDI) for thiamin is 1.5 mg for men and women and 1.7 mg for pregnant and lactating women, though the amounts vary depending on desired effect.

Vitamin B2

Vitamin B2, also known as riboflavin, was the second B vitamin to be discovered. In its pure form, it is a yellow-orange, water-soluble compound. Riboflavin is part of two enzymes essential for tissue respiration and the generation of energy from the metabolism of carbohydrates, amino acids and fats. This vitamin is vital for the normal reproduction, growth, repair and development of body tissues including skin, hair, nails, connective tissue and the immune system. There has been recent research that shows vitamin B2 may be helpful in reducing migraines.

A B2 deficiency, though severe deficiency is rare in developed countries, is possible because of antibiotic use, oral contraceptives and alcohol, all of which deplete or interfere with absorption and use of riboflavin. Symptoms of severe riboflavin deficiency include depression, loss of appetite, decreased sensitivity to touch, as well as red, swollen lips, mouth and tongue. This deficiency can lead to vitamin B2 anemia, thought to occur because red blood cell production is inhibited or because it causes cells to die too early.

Foods with high levels of riboflavin include organ meats, milk, yeast, cheese, oily fish, eggs and dark, green, leafy vegetables, as well as nuts, broccoli, currants and avocados. Riboflavin levels remain stable when food is cooked, but is destroyed by light, therefore making supplements the easiest way to obtain the proper amount of riboflavin into a diet.

The RDI for vitamin B2 is 1.7 mg per day for men and women and 2 mg per day for pregnant and lactating women.

Vitamin B3

Vitamin B3 is also known as niacin. In its pure form, it is a white powder, water-soluble and is more resistant to damage than the other B vitamins. This vitamin is one of the better known ways to help treat high Cholesterol, and has other cardiovascular functions. Niacin can be used in treating anxiety, circulatory problems and emotional or physical stress.

Deficiency is rare, but one of the first signs of niacin deficiency is pellagra. The skin becomes sensitive to light, then becomes dark, rough, thick and dry. Other symptoms include weakness and fatigue, anorexia, indigestion and skin eruptions. Deficiency of niacin can be caused by alcoholism, severely malnourished people, as well as people with cancer, protein, deficiencies and women taking oral contraceptives. The RDI for niacin is 20 mg per day for men and women.

Vitamin B3 is found in beef, pork, fish, milk, cheese, whole wheat, potatoes, corn and carrots. Because only small amounts of vitamin B3 in foods is pure niacin it is best to steam, bake or stir-fry vegetables to save as much of the vitamin as possible.

Vitamin B5

Vitamin B5, also known as pantothenic acid (PA), is important for the release of energy from food, growth, reproduction and normal physiological functions. PA assists in the manufacturing of coenzyme A, which plays a crucial role in the breakdown of fats and carbohydrates, it is also necessary for building cell membranes and the production of some neurotransmitters essential for normal nervous system function. PA also aids in antibody synthesis and is involved in wound healing.

A pantothenic acid deficiency has not been found natural in human beings, but has been induced experimentally. This deficiency causes adrenal glands to shrink, causing fatigue, headache, nausea, abdominal cramps, depression, sleep problems and personality changes. More severe symptoms include numbness, tingling of hands and feet, muscle cramps, impaired coordination, immune problems, dermatitis and itching. Toxicity is rare and the only reported overdosing symptom is diarrhea.

The RDI is 5 mg per day, but intakes can vary between 4 and 10 mg per day. Good sources of PA include yeast, liver, eggs, wheat germ, bran, peanuts, peas, meat, milk, poultry, whole grains, broccoli, mushrooms and sweet potatoes. Most fruits and vegetables contain small amounts of PA, but heat, food processing and canning destroys B5 in food.

Vitamin B6

Vitamin B6, or pyridoxine, is a family of chemically related compounds including pyridoxamine and pyridoxal which are found in animal products and pyridoxine, which is found in plants. The most common form found in foods and supplements is pyridoxine.

Necessary for the proper functioning of over 60 enzymes, vitamin B6 helps in the synthesis and breakdown of amino acids, in the conversion of amino acids to carbohydrates or fat and in the conversion of one type of fat to another.

Vitamin B6 deficiencies are most commonly found in adolescents, the elderly, those on restricted diets and alcoholics. Deficiency is frequently caused by exposure to radiation, tobacco use, air pollution, stress and the use of oral contraceptives. Symptoms of deficiency include irritability, weakness, drowsiness, depression and lack of appetite. It can cause convulsion in young children and it can affect the development of a baby's nervous system if the mother is vitamin B6 deficient during pregnancy. This vitamin is nontoxic but should be used carefully by diabetics as it has been shown to lower blood sugar. Vitamin B6 is used to treat asthma, cardiovascular disease, mood disorders and premenstrual syndrome.

Sources of vitamin B6 include chicken, fish, liver, kidneys, pork, eggs, milk, wheat germ and brewer's yeast. Long storage, canning, roasting or stewing can destroy vitamin B6. The most commonly available supplemental forms of this vitamin is pyridoxine hydrochloride and pyridoxine phosphate, which may be better absorbed. The RDI of vitamin B6 is 2 mg per day for men and women and 2.5 per day for pregnant or lactating women.

Vitamin B12

The last B vitamin to be identified is B12, also known as cobalamin, and is the only vitamin that contains an essential mineral, cobalt. This vitamin is essential for the metabolism of nerve tissue, fats and carbohydrates and the synthesis of proteins and for the health of the entire nervous system. Vitamin B12 is also important in the transport and storage of folate in cells and for conversion to its active form.

The body stores vitamin B12 in the liver, heart, kidneys, pancreas, brains, testes, blood and bone marrow making a deficiency very difficult, though possible over many years. Vitamin B12 deficiency disease is called pernicious anemia and is often accompanied by weight loss, weakness, pale skin and psychological disturbances. This deficiency is most commonly found in alcoholics, the elderly and strict vegetarians (as B12 is primarily found in animal products). No toxic effects from vitamin B12 have ever been reported.

Vitamin B12 can be consumed through oral supplementation, most widely found as cyanocoblalmin and hydroxycobalamin in a vitamin B12 injection, used in cases of B12 malabsorption. High levels of vitamin B12 are found in animal protein foods including oily fishes, crabs, oysters, eggs, milk products and meat. Because B12 is stored, the majority of 94 percent men and 83 percent of women meet the RDI guidelines - the highest percentage of all nutrients. 10 to 20 mcg per day of vitamin B12 is considered enough to maintain proper levels.

Other B Vitamins

All other vitamins in the vitamin B family are known by their chemical names: biotin, choline, folic acid, inositol and paraaminobenzoic acid (PABA). Biotin, choline and inositol and PABA have similar functions while folic acid is more closely related to those of vitamin B12.

Biotin is synthesized in the gut and helps incorporate amino acids into protein, synthesize sugar and fat molecules and plays an important role in carbohydrate metabolism. This B vitamin supports healthy bone marrow, sweat glands, nerve tissue, hair and skin, and it aids in cell growth and metabolism of fats and proteins. Biotin is also essential for the utilization of other Bcomplex vitamins.

Choline is a rare vitamin in that it crosses the blood-brain barrier into spinal fluid to be directly involved with chemical metabolism. This vitamin is important for disorders of the nervous system, such as Parkinson's disease and tardivedyskinesia, as well as for utilizing fats in the body, supporting weight loss in the process. Choline also assists in gallbladder regulation and liver function, nerve transmission, lecithin formation, hormone production, fat and cholesterol metabolism and it minimizes excess fat in the liver.

Inositol is vital for hair growth, lecithin formation and fat cholesterol metabolism. Also, it helps prevent hardening of the arteries and removes fats from the liver. Additionally, this vitamin plays a role in cell membrane structure and integrity and may help brain cell nutrition. Healthy inositol levels in the body can be reduced by high caffeine consumption.

The B vitamin PABA is important for its nourishment of the hair, its stimulation of cell growth and tissue repair and its usefulness as a sunscreen. It also contributes to the release of energy from carbohydrates, the synthesis of sugar molecules and the synthesis and breakdown of fatty acids. PABA, a part of the folic acid molecule, is found in many foods, including liver, rice and eggs. It is stored in body tissues and is synthesized by the natural bacteria in the intestines.

Folic acid has been found to have excellent effects when used preventively as well as therapeutically. Folic acid has been proven to help increase plasma folic acid levels and reduce homocysteine levels. Folic acid is critical in the prevention of spinal birth defects and pregnant women are urged to eat specially fortified foods or take supplements to protect against spina bifida.

The best source for folic acid is green, leafy vegetables such as spinach, kale, asparagus, broccoli and beats. Whole wheat bread and milk contain some folic acid, but exposure to light, heat, any type of cooking or an acid pH below 4 will destroy folic acid in food. The RDI for folic acid is 400 mcg per day for men and women, 800 mcg per day for pregnant women and 600 mcg per day while lactating.

References:

¹ Haas, E. Staying Healtly with Nutrition: The Complete Guide to Diet and Nutritional Medicine. Berkeley: Celestial Arts, 1992.

As Published in HEALTH SUPPLEMENT RETAILER