Fat soluble vitamins, as the name connotes, can dissolve in fat. This means your body can absorb them better if they are taken with dietary fat. They can be stored in your fatty tissues (adipose) or your liver, and are not eliminated as fast as water soluble vitamins.
1. Vitamin A
Vitamin A, or retinol, is for good vision. In the retina, an eye part, a form of vitamin A called retinal allows good light transmission from your surroundings to your brain. Therefore, vitamin A helps you see whether in good or in dim light. Additionally, it strengthens your bones and teeth. It also plays a significant role in the renewal of your cells by promoting cell division, and helps the immune system fight off infections. Vitamin A also keeps mucous membranes (such as in your skin, eyes, nose, mouth, throat and lungs) moisturized. Vitamin A deficiency causes night blindness, dry and rough skin, recurrent infections, slow growth, and brittle bones and teeth.
Sources of vitamin A in the retinol form include liver, butter, cheese, whole milk and egg yolks. Retinol is found in animal tissues. However, you can also get your vitamin A from plants as "provitamins" in the form of carotenoids (beta carotene and alpha carotene). Plant sources include green leafy vegetables, and orange or yellow fruits and vegetables. Note that the dietary reference intake (DRI) for this vitamin is only 3,000 micrograms RAE, so if you're taking supplements, don't go over this amount.
2. Vitamin D
Vitamin D, or cholecalciferol, is for bone and teeth development. It also enhances the absorption of calcium from the small intestine. A sufficient amount of this vitamin in your body preserves the calcium-phosphorus balance. Vitamin D deficiency, however, can cause rickets in children (long but soft bowed legs and flattened skulls) and osteomalacia in adults (weak bones and muscles).
Sources include vitamin D-fortified milk and dairy products, fish (salmon, sardines, herring), cod liver oil and egg yolk. It can also be synthesized in your skin when you're exposed to sunlight. When taking vitamin supplements, don't exceed the DRI of 50 micrograms. If you have inadequate sun exposure, however, you may take supplements that contain at least 800 IU of vitamin D.
3. Vitamin E
Vitamin E is a known antioxidant that protects cells from free radical damage. It also enhances the actions of vitamins A and C. The most active vitamin E form is called alpha-tocopherol. The DRI is 15 micrograms alpha-tocopherol.
Vitamin E sources include margarine, vegetable oils, green and leafy vegetables, nuts, whole grains, wheat germ, egg yolk and liver. Regular consumption of foods rich in vitamin E can help decrease the risk for heart disease and cancer.
4. Vitamin K
Vitamin K is essential in blood clot formation, therefore preventing hemorrhages. If you're taking anticoagulants (blood thinners) or antibiotics, or if you have a chronic diarrhea (Crohn's disease, inflammatory bowel syndrome), you may become vitamin K deficient. Consult your doctor regarding your vitamin K needs if you are taking these drugs or if you have any of these conditions. You can get vitamin K from green leafy vegetables and vegetable oils (canola, olive, soybean, cottonseed).