B complex vitamins are water soluble vitamins and consist of the following:

• Thiamine (Vitamin B1)
• Riboflavin (Vitamin B2)
• Niacin (Nicotinamide, Nicotinic Acid)
• Pyridoxine (Vitamin B6)
• Folic Acid
• Vitamin B12 (Cyanocobalamin)

Thiamine is also known as Anti-beriberi vitamin. Deficiency of thiamine leads to a condition called as Beriberi. Beriberi is of 2 types:

• Dry Beriberi which predominantly affects the nervous system and leads to irritability, fatigue, headache, calf muscle pain, difficulty in standing from sitting position, constipation, slow growth and gradual wasting. Patient on examination is found to have neuritis. In infants, it may lead to tremors, convulsions and squint.
• Wet Beriberi affects the heart, predominantly and leads to palpitations, a fast pulse, breathlessness and swelling over the feet. In infants (children less than 1 year of age) in addition leads to shrill cry, vomiting and bluish hue to the skin.

In addition, in infants a third-type of Beriberi may occur which is known as Aphonic Beri Beri in which the infant presents with hoarse cry which then leads to absent voice and finally may lead to breathlessness and swelling over the body.

Deficiency of Thiamine is quite rare as thiamine is present in cereals pulses, groundnuts and vegetables. Diagnosis of thiamine deficiency is made clinically. Dramatic improvement is seen in symptoms on supplementation with thiamine.

Rare genetic disorders can occur due to deficiency of enzymes in the body that process thiamine leading to anemia (low hemoglobin) and mental retardation. In these conditions, thiamine supplementation in high doses in required for a prolonged period of time.

Riboflavin: - Deficiency of riboflavin leads to ulcers on the tongue (red fiery tongue) known as glossitis or ulcers over the corners of the mouth and ulcers over the cornea with watering of eyes, intolerance to light and blurring of vision. If the pregnant woman is riboflavin deficient, growth and development of the baby is affected.

Riboflavin deficiency is rare as Vitamin B2 is present in milk, cheese, meat, eggs, fish, green leafy vegetables and whole grains. Diagnosis of riboflavin deficiency is made clinically and dramatic improvement is seen on supplementation with Vitamin B2.

Again, similar genetic disorders can occur due to deficiency of enzymes in the body and riboflavin supplementation in high dose can aid in its treatment.
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Niacin: - It is also known as anti pellagra vitamin. Deficiency of niacin is more prevalent in maize eating population. Pellagra is characterized by diarrhea, skin rash and mental deterioration with muscle weakness and loss of memory. Skin rash occurs predominantly in sun-exposed areas such as neck and back of hands leading to pigmented, scaly and cracked skin.

Niacin is present in adequate quantity in groundnuts, whole cereals, meat and fish. Diagnosis of pellagra is clinical and dramatic improvement is seen in symptoms on supplementation with niacin.

A genetic condition called as Hartnup's disease leads to a state of niacin dependency.

Pyridoxine: - Dietary deficiency of pyridoxine is rare and deficiency of pyridoxine usually occurs due to genetically inherited absence of an enzyme or secondary to some drugs such as prolonged use of Isoniazid for treatment of TB. Deficiency of pyridoxine leads to irritability, anemia (low hemoglobin), increased hearing, nausea, vomiting, seizures (fits) and wasting or loss of weight. Older children may develop neuritis. Pyridoxine deficiency can lead to persistent convulsions in an infant and such infants respond to intravenous pyridoxine dramatically.

Pyridoxine is present in good amounts in meat, fish, cereals and legumes.

Folic Acid: - Folic acid is essential for formation of red blood cells and its deficiency results in certain type of anemia. Deficiency of folic acid in the pregnant woman has been linked with spina bifida and neurological defect in the baby. Hence, pregnant women should be given folic acid. Folic acid deficiency is seen in rice-eating population.
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Good sources of folic acid are green leafy vegetables, eggs, fish and pulses. Overcooking and boiling destroys the folate in the food.

Vitamin B12:- Like Folic acid, Vitamin B12 is also essential for the formation of red blood cells and deficiency of Vitamin B12 leads to certain type of anemia (low hemoglobin). Deficiency of Vitamin B12 can also lead to paralysis and weakness of the limbs due to involvement of the nerves in the spinal cord. Dietary deficiency of Vitamin B12 is rare and is usually seen in children on exclusive vegetarian diet with inadequate intake of milk and plant food. Also deficiency of Vitamin B12 is seen in patients with "PERNICIOUS AWEMIA" due to absence of a factor called as 'Intrinsic Factor' in the stomach. Good sources of Vitamin B12 are milk, eggs and meat.

Last updated on 1-7-2006