Features Of Fat-soluble Vitamins

Vitamins A, D, E and K constitute fat-soluble vitamins. These vitamins absorb into the body with the assistance of dietary fat. If you have health problems preventing intestinal fat absorption, deficiencies of fat-soluble vitamins may arise. Many types of foods contain fat-soluble vitamins. Therefore, a balanced diet should contain adequate amounts of these vitamins for your body's requirements. The Institute of Medicine establishes dietary reference intakes, or DRI, of each vitamin for all age groups.

Fat-Soluble Vitamins

Each of the four fat-soluble vitamins plays a critical role within your body. After ingestion and absorption, they can be stored in your liver and fat cells. Your body uses them later, during times of need. Since your body stores fat-soluble vitamins, they don't need to be consumed daily. Small amounts last a long time. Consuming excess fat-soluble vitamins exceeds the body's storage ability and causes symptoms of vitamin toxicity.

Vitamin A

Vitamin A is important in your vision, bone growth, reproduction, and cellular processes. It promotes healthy tissues in respiratory, urinary and intestinal tracts. Vitamin A, when derived from animals, is in an active form and the most usable. It is called retinol. The vitamin A found in fruits and vegetables is provitamin A carotenoid. It is converted into active vitamin A within your body. Not all carotenoids have vitamin A activity.

Vitamin D

Vitamin D is not present in many foods but easily supplemented. Also, sunlight converts previtamin D into usable vitamin D within your skin, thus supplying your body with sufficient vitamin D. When adequate sunlight is not an option, dietary and supplemental vitamin D develops into a usable form during conversion in your liver or your kidneys. Active vitamin D is involved with cell, nerve and immune functions. Also, it assists in intestinal absorption of dietary calcium for proper blood calcium levels.

Vitamin E

Vitamin E is touted for its antioxidant activity. Antioxidants protect cells from damage, thus protecting you from such ailments as cardiovascular disease and cancer. Also, vitamin E is involved in the immune system, cellular functions and circulatory system health. It naturally occurs in eight different forms but only alpha-tocopherol is used by your body. Nuts, seeds and vegetable oils contain the most usable vitamin E, as well as some green leafy vegetables.

Vitamin K

Vitamin K is involved with several blood clotting processes. Blood clotting factors need to bind to calcium in seven vitamin K-dependant factors for proper clot formation to occur. It is the least stored of the fat-soluble vitamins and its depletion is rapid. Luckily, it is only needed in small amounts and is recycled within your body. It can be found in green leafy vegetables and some vegetable oils. Also, normal intestinal bacteria synthesize small amounts of vitamin K for absorption into your body through your gut.