B-COMPLEX VITAMINS
Eight of the water-soluble vitamins are known as the vitamin B-complex group:
Thiamin (vitamin B1),
Riboflavin (vitamin B2),
Niacin (vitamin B3),
Vitamin B6 (pyridoxine),
Folate (folic acid),
Vitamin B12,
Biotin and
Pantothenic acid.
The B vitamins are widely distributed in foods and their influence is felt in
many parts of the body. They function as coenzymes that help the body obtain
energy from food. The B vitamins are also important for normal appetite, good
vision, and healthy skin, nervous system, and red blood cell formation.
a) Thiamin: Vitamin B1
Thiamin, or vitamin B1, helps to release energy from foods, promotes normal
appetite, and is important in maintaining proper nervous system function.
Food Sources for Thiamin
Sources include peas, pork, liver, and legumes. Most commonly, thiamin is found in whole grains and fortified grain products such as cereal, and enriched products like
bread, pasta, rice, and tortillas. The process of enrichment adds back nutrients that are
lost when grains are processed. Among the nutrients added during the enrichment
process are thiamin (B1), niacin (B3), riboflavin (B2), folate and iron.
RDA (Required Daily allowance):
Males: 1.2 mg/day; Females: 1.1 mg/day
Thiamin Deficiency
Under-consumption of thiamin is rare due to wide availability of enriched grain
products. However, low calorie diets as well as diets high in refined and processed
carbohydrates may place one at risk for thiamin deficiency. Alcoholics are especially prone to thiamin deficiency because excess alcohol consumption often replaces food
or meals. Symptoms of thiamin deficiency include: mental confusion, muscle
weakness, wasting, water retention (edema), impaired growth, and the disease known as beriberi. Thiamin deficiency is currently not a problem in the United States.
Thiamin toxicity
No problem with overconsumption are known for thiamin.
b) Riboflavin: Vitamin B2
Riboflavin, or vitamin B2, helps to release energy from foods, promotes good vision,
and healthy skin. It also helps to convert the amino acid tryptophan (which makes up
protein) into niacin.
Food Sources
Sources include liver, eggs, dark green vegetables, legumes, whole and enriched
grain products, and milk. Ultraviolet light is known to destroy riboflavin, which is
why most milk is packaged in opaque containers instead of clear.
RDA:
Males: 1.3 mg/day; Females: 1.1 mg/day
Deficiency
Under consumption of riboflavin is rare. However, it has been known to occur with
alcoholism, malignancy, hyperthyroidism, and in the elderly. Symptoms of deficiency
include cracks at the corners of the mouth, dermatitis on nose and lips, light
sensitivity, cataracts, and a sore, red tongue.
Riboflavin toxicity
No problems with overconsumption are known for riboflavin.
c)Niacin: Vitamin B3, Nicotinamide, Nicotinic Acid
Niacin, or vitamin B3, is involved in energy production, normal enzyme function,
digestion, promoting normal appetite, healthy skin, and nerves.
Food Sources for Niacin
Sources include liver, fish, poultry, meat, peanuts, whole and enriched grain products.
RDA
Males: 16 mg/day; Females: 14 mg/day
Niacin Deficiency
Niacin deficiency is known to occur with alcoholism, protein malnourishment, low
calorie diets, and diets high in refined carbohydrates. Pellagra is the disease state that
occurs as a result of severe niacin deficiency. Symptoms include cramps, nausea,
mental confusion, and skin problems.
Niacin toxicity
Consuming large doses of niacin supplements may cause flushed skin, rashes, or liver
damage. Over consumption of niacin is not a problem if it is obtained through food.
d) Vitamin B6: Pyridoxine, Pyridoxal, Pyridoxamine
Vitamin B6, otherwise known as pyridoxine, pyridoxal or pyridoxamine, aids in protein metabolism and red blood cell formation. It is also involved in the body’s production of chemicals such as insulin and hemoglobin.
Food Sources for Vitamin B6
Sources include pork, meats, whole grains and cereals, legumes, and green, leafy
vegetables.
RDA
The RDA for vitamin B6 is 1.3 mg/day for adult males and females through age fifty.
Vitamin B6 Deficiency
Deficiency symptoms include skin disorders, dermatitis, cracks at corners of mouth, anemia, kidney stones, and nausea. A vitamin B6 deficiency in infants can cause mental
confusion.
Excess of Vitamin B6
Over consumption is rare, but excess doses of vitamin B6 over time have been known
to result in nerve damage.
e) Folate: Folic Acid, Folacin
Folate, also known as folic acid or folacin, aids in protein metabolism, promoting
red blood cell formation, and lowering the risk for neural tube birth defects. Folate may
also play a role in controlling homocysteine levels, thus reducing the risk for coronary
heart disease.
Food Sources for Folate
Sources of folate include liver, kidney, dark green leafy vegetables, meats, fish, whole
grains, fortified grains and cereals, legumes, and citrus fruits. Not all whole grain
products are fortified with folate..
RDA
The RDA for folate is 400 mcg/day for adult males and females. Pregnancy will
increase the RDA for folate to 600 mcg/day.
Folate Deficiency
Folate deficiency affects cell growth and protein production, which can lead to overall impaired growth. Deficiency symptoms also include anemia and diarrhea. A folate deficiency in women who are pregnant or of child bearing age may result in the delivery of a baby with neural tube defects such as spina bifida.
Folate toxicity
Over consumption of folate offers no known benefits, and may mask B12 deficiency as
well as interfere with some medications.
f) Vitamin B12: Cobalamin
Vitamin B12, also known as cobalamin, aids in the building of genetic material,
production of normal red blood cells, and maintenance of the nervous system.
Food Sources for Vitamin B12
Vitamin B12 can only be found only in foods of animal origin such as meats, liver,
kidney, fish, eggs, milk and milk products, oysters, shellfish. Some fortified foods may
contain vitamin B12.
RDA
The Recommended Dietary Allowance (RDA) for vitamin B12 is 2.4 mcg/day for
adult males and females
Vitamin B12 Deficiency
Vitamin B12 deficiency most commonly affects strict vegetarians (those who eat
no animal products), infants of vegan mothers, and the elderly. Symptoms of
deficiency include anemia, fatigue, neurological disorders, and degeneration of nerves resulting in numbness and tingling. In order to prevent vitamin B12 deficiency, a dietary supplement should be taken. Some people develop a B12 deficiency because they cannot absorb the vitamin through their stomach lining.
This can be treated through vitamin B12 injections.
Vitamin B12 toxicity
No problems with overconsumption of vitamin B12 are known.
g) Biotin
Biotin helps release energy from carbohydrates and aids in the metabolism of fats,
proteins and carbohydrates from food.
Food Sources for Biotin
Sources of Biotin include liver, kidney, egg yolk, milk, most fresh vegetables, yeast
breads and cereals. Biotin is also made by intestinal bacteria.
RDA
The Adequate Intake (AI) for Biotin is 30 mcg/day for adult males and females
Biotin Deficiency
Biotin deficiency is uncommon under normal circumstances, but symptoms
include fatigue, loss of appetite, nausea, vomiting, depression, muscle pains, heart
abnormalities and anemia.
Biotin toxicity
No problems with overconsumption are known for Biotin.
h) Pantothenic Acid
Pantothenic Acid is involved in energy production, and aids in the formation of
hormones and the metabolism of fats, proteins, and carbohydrates from food.
Food Sources for Pantothenic Acid
Sources include liver, kidney, meats, egg yolk, whole grains, and legumes.Pantothenic
Acid is also made by intestinal bacteria.
RDA
The Adequate Intake (AI) for Pantothenic Acid is 5 mg/day for both adult males and
females.
Pantothenic Acid Deficiency
Pantothenic Acid deficiency is uncommon due to its wide availability in most foods.
Pantothenic Acid toxicity
No problems with overconsumption are known for Pantothenic Acid. Rarely,
diarrhoea and water retention will occur with excessive amounts.
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