Vitamins are a group of substances that are needed, in very small amounts, for your body to grow and develop normally.  There are two broad categories of Vitamins based upon how they are absorbed:

• Fat-soluble vitamins: Vitamins A, D, E and K are Fat-soluble vitamins. They dissolve in fat and then absorbed from intestine.
• Water-soluble vitamins: Vitamins C and B complex (B1, B2, B3, B5, B6, B7, B12 and Folic acid).  They dissolve in water and are absorbed directly into the blood from the intestine.

Vitamins are not synthesized by humans (except Vitamin D and Vitamin K), so have to be ingested in diet or supplement.

Vitamin A Deficiency

Vitamin A is important for  vision, integrity of tissues and immune system. Its primary sources include green leafy vegetables, carrot, sweet potato, fish, liver, whole milk, egg yolk, and butter. Children and pregnant or breastfeeding mothers need more Vitamin A. Children who are malnourished or have measles have greater risk of having Vitamin A deficiency.

Vitamin A deficiency can lead to:

• Night blindness;
• Dryness of  outer lining of eyeball (conjunctiva and cornea);
• Corneal ulceration and blindness;
• Poor bone growth;
• Skin changes (damage to hair follicles, skin glands); or
• Increase risk of infections like measles.

In many countries, all children between 6 months and 5 years of age are routinely given Vitamin A two times in a year and every pregnant woman is given a dose of Vitamin A at the time of delivery. This routine supplementation of Vitamin A has contributed to significant decrease in blindness resulting from Vitamin A deficiency and under-five child mortality, particularly resulting from complications of measles.

Vitamin D Deficiency

Vitamin D is needed for maintaining strong bones. It helps your body absorb calcium from your intestine and to maintain calcium phosphorus balance required for bone mineralization. Vitamin D has 2 sources:

• Dietary Source: from milk, milk products, egg yolk, liver, fish.
• Synthesized in the body (in skin, liver and kidney) with the help of sunlight.

Deficiency of Vitamin D can lead to defective mineralization of bone:

• In children this defect can cause rickets – soft weak bones which become deformed.
• In adults it causes osteomalacia or soft bones.

Typical causes of Vitamin D deficiency are: diet poor in Vitamin D,  failure of absorption, inadequate exposure to sunlight and diseases of liver or kidneys. Some medications (anticonvulsants) can also cause Vitamin D deficiency. Some symptoms of Vitamin D deficiency include poor growth, bow legs in children and bone pain and muscle weakness in adults. Blood test helps in the diagnosis of the deficiency.

Vitamin D supplementation typically corrects the deficiency. However, it is important to avoid excess consumption of Vitamin D, as such excess consumption can be harmful.

Vitamin E Deficiency

Vitamin E is an antioxidant that helps protect cells from damage caused by free radicals. It is found in eggs, meat, oil and green leafy vegetables. Vitamin E deficiency can cause nerve and muscle damage that results in loss of sensation in the arms and legs or muscle weakness.

Deficiency of Vitamin E in preterm babies can cause damage to red blood cells. Vitamin E supplementation can be helpful in treatment.

Vitamin K Deficiency

Vitamin K helps in blood clotting process. Clotting factors are made in the liver. Sources of Vitamin K are diet (green leafy vegetables such as spinach, broccoli) and bacteria in the intestine. Deficiency of Vitamin K leads to excess bleeding.

Causes of Vitamin K deficiency are use of medicine (blood thinner like Warfarin) that block action of Vitamin K or antibiotics that kill bacteria in the intestine. Vitamin K deficiency is common in newborns. Supplementation typically corrects the deficiency.

Vitamin C Deficiency

Vitamin C (Ascorbic acid) is an antioxidant that is needed for healthy skin and connective tissue. It promotes healing and helps the body absorb iron. Vitamin C comes from fruits, particularly citrus fruits (orange, grape) and vegetables like tomatoes, broccoli, and greens.

Deficiency of Vitamin C may cause Scurvy – anemia, gum bleeding, bruising and poor wound healing. It is treated with supplementation.

Vitamin B Deficiency:

There are eight types of Vitamins in Vitamin B Complex, namely B1 (Thiamine), B2 (Riboflavin), B3 (Niacin), B5 (Pantothenic Acid), B6 (Pyridoxine), B7 (Biotin), B12 and Folic Acid. These vitamins help convert food we eat into energy. Vitamin B12 and Folic acid also help form red blood cells. Sources of Vitamin B complex are fish, poultry, meat, eggs, dairy products, leafy green vegetables, beans, and peas.

Vitamin B deficiency causes different symptoms depending on the specific Vitamin B that is deficient. Lack of Vitamin B12 and Folic Acid can cause anemia. Vitamin B12 deficiency, which occurs mainly in strict vegetarians, also causes tingling and numbness of limbs due to nerve damage. Vitamin B6 deficiency can occur due to medicine for TB. Its symptoms are numbness and tingling.

Deficiency of Vitamin B1 can occur due to excess alcohol drinking. It causes a Beriberi, which leads to swelling of body due to heart failure or altered sensorium due to damage to the brain.

Deficiency of Vitamin B2 causes soreness and cracks in lips and mouth. Deficiency of Vitamin B3 causes pellagra, which manifests with skin rashes, diarrhea and forgetfulness.

Vitamin B deficiency can be corrected by appropriate supplementation.