Vitamins

Why Vitamins?

The foods we eat contain nutrients that provide energy and other things the body needs.
Most of the nutrients in food fall into three major groups; carbohydrates, fats and proteins and three minor groups; vitamins, minerals and water.

Vitamins are organic substances present in food and required by the body in small amounts (thus the term, micronutrients) for regulation of metabolism and maintenance of normal growth and functioning.
Though the body requires these nutrients in smaller quantities, they are very essential and their absence can result in very serious health problems.
Vitamins are divided into two major groups; water soluble vitamins (dissolve in water) and fat-soluble vitamins (dissolve in fat).

The water soluble vitamins;

• These are the B complex vitamins and vitamin C.
• Examples are Vitamin B1 (Thiamin), Vitamin B2 (Riboflavin), Vitamin B3 (Niacin) Vitamin B6 (Pyridoxine), Vitamin B12 (Cynocobalamine/Cobalamine), Folic Acid (Folate/Folacin), Pantothenic Acid, Biotin and Vitamin C (Ascorbic Acid).
• Excess amounts of these are excreted in the urine, thus the nutrients require a daily replacement in the diet.

The fat-soluble vitamins;

• These are Vitamin A, Vitamin D, Vitamin E, and Vitamin K.
• Examples are Vitamin B1 (Thiamin), Vitamin B2 (Riboflavin), Vitamin B3 (Niacin) Vitamin B6 (Pyridoxine), Vitamin B12 (Cynocobalamine/Cobalamine), Folic Acid (Folate/Folacin), Pantothenic Acid, Biotin and Vitamin C (Ascorbic Acid).
• Excess of these are stored in the liver and fatty tissues thus do not require daily replacement.

1. The Water Soluble Vitamins

Vitamins B1 (THIAMINE)

• Common food sources
  Pork, liver, whole grains, enriched grain products, peas, meat, legumes.
• Major functions
  Helps release energy from foods; promotes normal appetite; important in nervous system function.
• Deficiency symptoms
  Mental confusion; muscle weakness, wasting; edema; impaired growth; beriberi.
• Overconsumption symptoms
  None known.
• Stability in foods
  Losses depend on cooking method, cooking length and alkalinity of the cooking medium; destroyed by sulfite used to treat dried fruits such as apricots; dissolves in cooking water.

Vitamin B2 (RIBOFLAVIN)

• Common food sources
  Liver, milk, dark green vegetables, whole and enriched grain products, eggs.
• Major functions
  Helps release energy from foods; promotes good vision, healthy skin.
• Overconsumption symptoms
  None known.
• Stability in foods
  Sensitive to light; unstable in alkaline solutions.

Vitamin B3 (NIACIN)

• Common food sources
  Liver, fish, poultry, meat, peanuts, whole and enriched grain products.
• Major functions
  Assists in energy production from foods; aids digestion, promotes normal appetite; promotes healthy skin, nerves.
• Deficiency symptoms
  Skin disorders; diarrhea; weakness; mental confusion; irritability.
• Overconsumption symptoms
  Abnormal liver function; cramps; nausea; irritability.

Vitamin B6 (PYRIDOXINE)

• Common food sources
  Pork, meats, whole grains and cereals, legumes, green, leafy vegetables.
• Major functions
  Aids protein metabolism and absorption; aids in red blood cell formation; helps body use fats.
• Deficiency symptoms
  Skin disorders, dermatitis, cracks at corners of mouth; irritability; anemia; kidney stones; nausea; smooth tongue.
• Overconsumption symptoms
  None known.
• Stability in foods
  Considerable losses during cooking.

Vitamin B12 (CYNOCOBALAMINE/ COBALAMINE)

• Common food sources
  Found only in animal foods: meats, liver, kidney, fish, eggs, milk and milk products, oysters, shellfish.
• Major functions
  Aids in building of genetic material; aids in development of normal red blood cells; maintenance of nervous system.
• Deficiency symptoms
  Pernicious anemia; neurological disorders; degeneration of peripheral nerves that may cause numbness, tingling in fingers and toes.
• Overconsumption symptoms
  None known.

Folic Acid (FOLATE / FOLACIN)

• Common food sources
  Liver, kidney, dark green leafy vegetables, meats, fish, whole grains, fortified grains and cereals, legumes, citrus fruits.
• Major functions
  Aids in protein metabolism; promotes red blood cell formation; prevents birth defects homocysteine levels and thus coronary heart disease risk.
• Deficiency symptoms
  Anemia; smooth tongue; diarrhea.
• Overconsumption symptoms
  May mask vitamin B12 deficiency (pernicious anemia).
• Stability in foods
  Easily destroyed by storing, cooking and other processing.

Pantothenic Acid

• Common food sources
  Liver, kidney, meats, egg yolk, whole grains, legumes; also made by intestinal bacteria.
• Major functions
  Involved in energy production; aids in formation of hormones.
• Deficiency symptoms
  Uncommon due to availability in most foods; fatigue; nausea, abdominal cramps; difficulty sleeping.
• Overconsumption symptoms
  None known.
• Stability in foods
  About half of pantothenic acid is lost in the milling of grains and heavily refined foods.

Biotin

• Common food sources
  Liver, kidney, egg yolk, milk, most fresh vegetables, also made by intestinal bacteria.
• Major functions
  Helps release energy from carbohydrates; aids in fat synthesis.
• Deficiency symptoms
  Uncommon under normal circumstances; fatigue; loss of appetite, nausea, vomiting; depression; muscle pains; anemia.
• Overconsumption symptoms
  None known.

Vitamin C (ASCORBIC ACID)

• Common food sources
  Citrus fruits, broccoli, strawberries, melon, green pepper, tomatoes, dark green vegetables.
• Major functions
  Formation of collagen (a component of tissues), helps hold them together; wound healing; maintaining blood vessels, bones.
• Deficiency symptoms
  Bleeding gums; wounds don't heal; bruise easily; dry, rough skin; scurvy; sore joints and bones; increased infections.
• Overconsumption symptoms
  Normally: Nontoxic; rebound scurvy when high doses discontinued;
  Severe: diarrhea, bloating, cramps; increased incidence of kidney problems.
• Stability in foods
  Most unstable under heat, drying, storage; very soluble in water, leaches out of some vegetables during cooking;
2. The Fat Soluble Vitamins

Vitamnin A (CAROTENE)

• Common food sources
  Vitamin A; liver, vitamin A fortified milk and dairy products, butter, whole milk, cheese, egg yolk.
  Provitamin A; carrots, leafy green vegetables, sweet potatoes, pumpkins, winter squash, apricots, cantaloupe.
• Major functions
  Helps to form skin and mucous membranes and keep them healthy, thus increasing resistance to infections; essential for night vision; promotes bone and tooth development. Beta carotene is an antioxidant and may protect against cancer.
• Deficiency symptoms
  Mild: night blindness, diarrhea, intestinal infections, impaired vision.
  Severe: inflammation of eyes, keratinization of skin and eyes. Blindness in children.
• Overconsumption symptoms
  Mild: nausea, irritability, blurred vision.
  Severe: growth retardation, enlargement of liver and spleen, loss of hair, bone pain, increased pressure in skull, skin changes.

Vitamin D

• Common food sources
  Vitamin D-fortified dairy products, fortified margarine, fish oils, egg yolk. Synthesized by sunlight action on skin.
• Major functions
  Promotes hardening of bones and teeth, increases the absorption of calcium.
• Deficiency symptoms
  Severe: rickets in children; osteomalacia in adults.
• Overconsumption symptoms
  Mild: nausea, weight loss, irritability.
  Severe: mental and physical growth retardation, kidney damage, movement of calcium from bones into soft tissues.

Vitamin E

• Common food sources
  Vegetable oil, margarine, butter, shortening, green and leafy vegetables, wheat germ, whole grain products, nuts, egg yolk, liver.
• Major functions
  Protects vitamins A and C and fatty acids; prevents damage to cell membranes. Antioxidant
• Deficiency symptoms
  Almost impossible to produce without starvation; possible anemia in low birth-weight infants.
• Overconsumption symptoms
  Normally: nontoxic
  Severe: nausea, digestive tract disorders.

Vitamin K

• Common food sources
  Dark green leafy vegetables, liver; also made by bacteria in the intestine.
• Major functions
  Helps blood to clot.
• Deficiency symptoms
  Excessive bleeding.
• Overconsumption symptoms
  None reported.

General Recommendations for vitamin intake

• Healthy people can obtain all the vitamins and minerals they need from eating a variety of foods.
• Taking supplements does not guarantee protection against disease.
• Large doses of either single nutrient supplements or high potency vitamin-mineral combinations may be harmful.
• Vitamin deficiency is rare unless a person's diet is limited and lacks variety.
• Do not take self-prescribed single nutrient supplements without first consulting a physician or registered dietitian.

NB: certain individuals have special needs and may benefit from taking a supplement. They include the following: include the following:
• People with limited food intake, such as chronic dieters and some elderly, have difficulty meeting their nutrient needs.
• Older adults may benefit from supplements of B-12, vitamin D, and calcium.
• Iron supplementation may be important for women of childbearing age, pregnant women, and teenage girls.
• Post-menopausal women and adult men are not likely to be iron deficient and therefore do not need iron supplementation.
• Some vegetarians, especially strict vegans who eat no meat, dairy products or eggs, may not receive adequate amounts of iron, calcium, zinc and vitamin B-12.
• Infants and children who receive less than 1 quart per day of vitamin D fortified formula or milk.
• Adolescents who consume less than 400 IU/day of vitamin D.
• Women who are trying to or may become pregnant have additional folate needs of 400 µg/day.
• Individuals with dark skin or who do not get enough sunlight, may not make sufficient amounts of vitamin D from sun exposure, and could benefit from a supplement.
• Individuals with certain diseases or physiological conditions may require supplementation.
• Newborn infants are given vitamin K to help their blood clot.
• Pregnant or breastfeeding women require higher levels of many nutrients, especially folacin, iron and calcium.
• Adequate folate is particularly important before pregnancy and during the first trimester to prevent neural tube defects. The addition of folic acid to grains and cereals helps to increase the amount of folate people can obtain from foods.

References

1. WHO dietary and physical activity guidelines for Ghana, Ministry of Health, December 2009.

Disclaimer:

• This article is not meant for diagnosis and / or treatment of diseases. • Always consult with your dietician or physician before embarking on any dietary regimen.
• Always consult with your dietician or physician before embarking on any dietary regimen.