The substance named as vitamin B by the early investigators was discovered to contain a large number of vitamins. Because of the close bond between them were later collectively referred to as the B complex vitamins. B complex contains eight vitamins and out of these we will discuss here only three namely thiamine (vitamin B1 ), riboflavin (vitamin B2), and niacin (vitamin B4). This is because a definite deficiency disease has been found to occur in the absence of each of them and a mixed diet, which contains these three vitamins usually, contains the rest of the members of B complex group.

Deficiency of vitamin B1 (or Thiamine)

The disease caused by the lack of vitamin B1 or thiamine is known as BERI-BERI. Without vitamin B1 cells cannot utilize oxygen for energy, and nervous system and muscles do not perform their function properly. Individual lacking vitamin B1 in diet suffers from muscle pain, digestive disturbances, weakness, water logging of tissues, anaemia, lack of apetite, constipation and nervous disturbances. Nervous disturbances may include mental depression, moodiness, forgetfulness confusion and fear. Extreme deficiency of vitamin B1 also leads to paralysis or heart failure.

Vitamin B1 helps in carbohydrates metabolism and so the disease beri-beri is common in the areas where the diet contains a large amount of carbohydrates and small amounts of vitamin B1. The disease beri-beri was first observed amongst Japanese sea-men who were largely fed on polished rice. Cereals such as rice, wheat and barely contain B complex vitamins particularly in the outer covering of the grain. This mean s polished rice and white flour have lost most of the important vitamins. Therefore, a diet, which consists of only polished or dehusked rice and nothing else, lacks vitamin B1. Vitamin B1 cannot be stored in the body so this must be included our diet every day. The use of baking soda in cooking destroys vitamin B1 and its use should be avoided. As the vitamin is water soluble, so use of excess water in cooking and then discarding this excess water should be avoided as it results in loss of vitamin B1 in the diet.


Pulses, nuts, beans oil seeds and whole grain cereals are good sources of vitamin B1. Leafy green vegetables, eggs, fish and meat also contain a good amount of vitamin B1 in them.

Deficiency of vitamin B2 (or Riboflavin)

Riboflavin or vitamin B2 like thiamine is also involved in cell respiration and enables the body to use carbohydrates. Deficiency of this vitamin affects eyes skin and nerves. Eyelids become rough and eyes become sensitive to bright sunlight. This condition is known as photophobia. Cracks appear at the corners of the mouth, lips become inflected, the mouth and tongue become sore. This is known as riboflavinosis.

Best sources of vitamin B2 are milk, eggs, peas, beans, pulses, whole grain products and green leafy vegetables.


Deficiency of vitamin B4 (or Nicotinic Acid)

Vitamin B4 is important for the skin and for the nervous system. Deficiency of vitamin B4 causes a disease known as PELLAGRA. The skin becomes rough, scaly and dark. Loss off strength, mental depression, soreness in the tongue, skin eczema, diarrhea, nervousness, dizziness and muscular weakness are the symptoms of pellagra. Pellagra is common among those people who live on a maize diet because maize interferes with the absorption of vitamin B4 in the body.

Liver of animals, pulses, milk, eggs, groundnuts, fresh green vegetables and whole grains contain good amount of niacin.