Vitamins are natural substances found in plants and animals and known as essential nutrients for human beings. The name vitamin is obtained from “vital amines” as it was originally thought that these substances were all amines. The human body uses these substances to stay healthy and support its many functions. There are two types of vitamins: water-soluble and fat-soluble.
The body needs vitamins to stay healthy and a varied diet usually gives all the vitamins needed. Vitamins do not provide energy (calories) directly, but they do help regulate energy-producing processes. With the exception of vitamin D and K, vitamins cannot be synthesized by the human body and must be obtained from the diet. Vitamins have to come from food because they are not manufactured or formed by the body. There are 13 essential vitamins and each one has a special role to play within the body, helping to regulate the processes such as cell growth and repair, reproduction, and digestion. Vitamin B-6, Niacin, Natural Vitamin E, and Zinc: Support sexual function in men.

There are several roles for vitamins and trace minerals in diseases

i. Deficiencies of vitamins and minerals may be caused by disease states such as malabsorption;

ii. Deficiency and excess of vitamins and minerals can cause disease in and of themselves (e.g., vitamin A intoxication and liver disease);

iii. Vitamins and minerals in high doses may be used as drugs (e.g., niacin for hypercholesterolemia).

Vitamins are essential for the normal growth and development of a multi-cellular organism. The developing fetus requires certain vitamins and minerals to be present at certain times. If there is serious deficiency in one or more of these nutrients, a child may develop a deficiency disease. Deficiencies of vitamins are classified as either primary or secondary.

i. Primary Deficiency: A primary deficiency occurs when you do not get enough of the vitamin in the food you eat.

ii. Secondary Deficiency: A secondary deficiency may be due to an underlying disorder that prevents or limits the absorption or use of the vitamin.

Types of Vitamins

Vitamins, one of the most essential nutrients required by the body and can be broadly classified into two main categories i.e., water-soluble vitamins and fat-soluble vitamins. 


Water-soluble vitamins cannot be stored in the body, so we need to get them from food every day. They can be destroyed by overcooking. These are easily absorbed by the body. The human body doesn’t store large amounts of water-soluble vitamins. B-complex vitamins and vitamin C are water-soluble vitamins that are not stored in the body and must be replaced each day. These vitamins are easily destroyed or washed out during food storage and preparation. They are eliminated in urine so, the body needs a continuous supply of them in diets.
Proper storage and preparation of food can minimize vitamin loss. To reduce vitamin loss, refrigerate fresh produce, keep milk and grains away from strong light, and use the cooking water from vegetables to prepare soups. An excess of water-soluble vitamins should not result in any side effects as they will disperse in the body fluids and voided in the urine. 
Nine of the water-soluble vitamins are known as the B-complex group: Thiamin (vitamin B1), Riboflavin (vitamin B2), Niacin, Vitamin B6, Folate, Vitamin B12, Biotin, Pantothenic acid, and Vitamin C.


The fat-soluble vitamins include vitamins A, D, E, and K – since they are soluble in fat and are absorbed by the body from the intestinal tract. The human body has to use bile acids to absorb fat-soluble vitamins. Once these vitamins are absorbed, the body stores them in body fat. When we need them, our body takes them out of storage to be used. Eating fats or oils that are not digested can cause shortages of fat-soluble vitamins. 
Fat-soluble vitamins should not be consumed in excess as they are stored in the body and an excess can result in side effects. An excess of vitamin A may result in irritability, weight loss, dry itchy skin in children and nausea, headache, diarrhea in adults. 

Characteristics of the vitamins are:

1.    Most of the vitamins have been artificially synthesized.

2.    Some of the vitamins are soluble in water and others are fat-soluble.

3.    Some vitamins are synthesized in the body. Some members of the vitamin B complex are synthesized by microorganisms in the intestinal tract.

4.    Vitamins are partly destroyed and are partly excreted.

5.    Vitamins can be stored in the body to some extent, for example, the fat-soluble vitamins are stored in the liver and subcutaneous tissue.

6.    Vitamins can perform their work in very small quantities.