Since childhood, we have been taught that vitamins are the most important compounds required for a healthy body. We therefore include fresh fruits and vegetables in our diet to meet requirements of body. We all know the different vitamins required by the body system: vitamins A, C, D, E, K, and the B complex vitamins. These vitamins are classified as fat-soluble and water-soluble vitamins.

Fat-soluble Vitamins ~ Definition
The vitamins that are soluble in fat or lipids are termed fat-soluble or lipid-soluble vitamins. These are:
  • Vitamin A
  • Vitamin D
  • Vitamin E
  • Vitamin K
On the basic level, these vitamins are similar to each other structurally. They are dissolved in the lipids present in the body, and stored within the body for further use.

Water-soluble Vitamins ~ Definition
The vitamins that are soluble in water are termed as water-soluble vitamins. These include all the 8 B group vitamins, and vitamin C. As they are water-soluble, they cannot be stored within the body.

What is the Difference Between Fat-soluble and Water-soluble Vitamins
After going through the definitions, you must have got the general idea about what these vitamins are all about. Apart from their solubility, there are few other differences that have been summarized in the following table.

Fat-soluble Vitamins Water-soluble Vitamins
These vitamins are stored in the liver and other fatty tissues. Water-soluble vitamins cannot be stored within the body.
When the body needs fat-soluble vitamins, fat globules called chylomicrons are released to absorb these vitamins. These vitamins travel through the lymphatic system, and enter the blood stream for further use. Water-soluble vitamins are absorbed immediately after they enter the body. They travel through the bloodstream, are used up as required, and the excess are released into the urinary tract, from where they are flushed out through the urine.
These vitamins help to form the structural components of cells, and are required for repairing the damage due to daily wear and tear of tissues. The functions of fat-soluble vitamins include:
1. Vitamin E functions as an antioxidant, protects fatty acids and red blood cells from destruction, as well as maintains the balance of vitamin A and C.
2. Vitamin D helps to regulate the levels of calcium and phosphorous within the bloodstream by absorbing them from blood, and depositing them in bones.
3. The benefits of vitamin A include maintaining vision power, proper tissue growth and differentiation, as well as strengthening the immune system.
4. Vitamin K is essential for the metabolism of food into energy, blood clotting, and normal bone growth.
Water-soluble vitamins help keep the body healthy, and boost the immune system. The functions of these vitamins include:
1. Vitamin B helps in conversion of carbohydrates into glucose, thus providing energy to the body.
2. Biotin is essential for the proper growth of the body.
3. Vitamin C is a powerful antioxidant, and protects from damage by reactive oxygen species.
4. The benefits of vitamin B 12 include production of antibodies, folacin function, and maintenance of nerve tissues.
5. Folacin helps in synthesis of DNA, and cell division.

You should consume a balanced diet everyday, in order to meet the body's nutrient requirements. Each nutrient is required for certain structural and functional roles in the body.