This vitamin is divided into several subgroups numbered 1, 2, 3, 5, 6 and 12. All are water-soluble and occur in dairy products, meats and leafy vegetables. Vitamin B1 has the chemical name of thiamin, B2 is riboflavin and B5 is pantothenic acid. Vitamin B6 (pyridoxine) may be useful in mouth inflammation, morning sickness and nervous tension. Vitamin B12 (cyanocobalamin) is used as an injection to treat pernicious anemia. Nicotinic acid (vitamin B3) is specifically found in peanuts, meat, grain and liver. It is used in the treatment of certain types of headaches, nervous disorders, poor circulation and blood diseases.
“It is almost impossible to have a lack of only one in the group,” says Dr. Warwick Carter in his book The Complete Family Medical Guide. “If one is missing, several will usually be missing. A deficiency may cause anemia and other blood diseases. Beriberi is caused by a lack of vitamin B1, pellagra by a lack of vitamin B3, while pernicious anemia is due to a lack of vitamin B12. A lack of vitamin B6 (pyridoxine), may be an uncommon side effect of some medications (e.g. isoniazid, penicilliamine), genetic disorders and in poor nutrition. It causes epileptic-like seizures, dermatitis, mouth sores and dryness, vomiting, weakness and dizziness. The blood levels of pyridoxine can be measured to confirm the diagnosis, which is easily corrected by vitamin B6 supplements.
“Excessive blood levels of any of the B group vitamins may be due to
taking too many vitamin B supplements. Usually there are no serious effects
as excess passes out in the urine. Very high doses of pyridoxine (vitamin
B6) may cause nerve damage and poor coordination, numbness around the
mouth, clumsiness, muscle weakness and loss of position sense. Very high
doses of niacin (vitamin B3) may cause severe flushing, itchy skin, diarrhea
and liver damage. Long term complications are uncommon,” says Dr. Carter.