Mayo Health Care
The Importance Of Fat Soluble Vitamins A, E, D and K
What are vitamins? A vitamin is an organic (carbon-containing) chemical compound your body must have in very small amounts for normal growth, metabolism (creating energy in your cells), and health. Vitamins are needed to make enzymes and hormones, which are important substances human body uses to make all the chemical reactions, needed to live. Your body has no way to create vitamin molecules itself, so the vitamin molecules must come in through food that you eat. Most of us get enough of vitamins from our food, but it may be necessary for some people to take a vitamin supplement, because an ongoing shortage of vitamins will lead to failed health, weakness, susceptibility to disease. The body needs at least 13 different vitamins to function properly: Vitamin A - Retinol; Vitamin B complex (B1 - Thiamine; B2 - Riboflavin; B3 - Niacin; B6 - Pyridoxine; B12 - Cyanocobalamin; B9 - Folic acid; B5 - Pantothenic acid; H - Biotin); Vitamin C - Ascorbic acid; Vitamin D - Calciferol (can be obtained through sunlight); Vitamin E - Tocopherol; Vitamin K - Menaquinone. There are two types of vitamins: fat soluble and water soluble.
Fat soluble vitamins Vitamins A, E, D and K are fat-soluble, they dissolve in fat but not water. Once these vitamins are absorbed by the body, they are stored mostly in the fatty tissues and in the liver. Fat-soluble vitamins can be stored in your body for up to six months. The liver provides the primary storage tissue for vitamins A and D. Vitamin E is stored mainly in body fat and to a lesser extent in reproductive organs.
Relatively little vitamin K is stored. When you need these vitamins, your body takes them out of storage to be used. Because you can store these vitamins, you don't have to get a supply of them every day. However, eating fats or oils that are not digested can cause shortages of fat-soluble vitamins. On the other hand, getting too much of these vitamins, particularly vitamins A and D, can lead to toxic levels in the body and cause problems. Vitamin A (Retinol) Vitamin A, also called retinol, is a fat-soluble vitamin that has many functions in the body. It helps the eyes adjust to light changes, plays an important role in bone growth, tooth development, reproduction, cell division and gene expression. Vitamin A helps regulate the immune system, which helps prevent or fight off infections by making white blood cells that destroy harmful bacteria and viruses. Also, the skin, eyes and mucous membranes of the mouth, nose, throat and lungs depend on vitamin A to remain moist. Signs of vitamin A deficiency are night blindness, dry scaly skin, low resistance to infection, poor tooth formation, slower bone growth, formation of gall and kidney stones, sinus troubles, poor digestion, ear abscesses.
Excess alcohol intake depletes vitamin A stores. Food sources of Vitamin A: liver, butter, whole milk, cheese, egg yolk. Food sources for Provitamin A: carrots, leafy green vegetables, sweet potatoes, pumpkins, winter squash, apricots, cantaloupe. Vitamin D (Calciferol) Vitamin D is a fat soluble vitamin that is found in food and can also be made in your body after exposure to ultraviolet (UV) rays from the sun. Sunshine is a significant source of vitamin D because UV rays from sunlight trigger vitamin D synthesis in the skin. Vitamin D plays a critical role in the body's use of calcium and phosphorous. It increases the amount of calcium absorbed from the small intestine and helps form and maintain bones. Vitamin D also works together with other vitamins, minerals, and hormones to promote bone mineralization. Without vitamin D, bones can become thin, brittle, or misshapen. Children especially need adequate amounts of vitamin D to develop strong bones and healthy teeth.
Lack of Vitamin D may cause rickets and fragile bones, bowed legs, enlargement of the elbows and wrists joints, also muscle twitching and muscle cramps. Excessive amounts of Vitamin D may result in general depression, abnormal calcium deposits in the blood vessel walls, liver, lungs, kidneys, and stomach. It may also lead to diarrhea and have other severe toxic effects. Food sources of Vitamin D: Cod liver oil, salmon, mackerel, fortified milk and cereal tuna fish, sardines, eggs, liver (beef). Vitamin E (Tocopherol) Vitamin E is a fat-soluble vitamin. Vitamin E helps in the overall health of the sexual organs, is good for the skin and helps promote its healing. Is good for the heart and lungs. Vitamin E acts as an antioxidant, protecting vitamins A and C, red blood cells and essential fatty acids from destruction. Lack of Vitamin E may cause sterility in both sexes, loss of hair, and miscarriage. Food sources of Vitamin E: wheat germ oil, sunflower seed kernels, sunflower oil, safflower oil, hazelnuts, peanuts, corn oil, spinach, broccoli, kiwi, mango.
Vitamin K (Menaquinone) Vitamin K plays an essential role in normal blood clotting and helps promote bone health. Food sources of Vitamin K: dark green leafy vegetables, liver, olive oil, cottonseed oil. Vitamin K is also made by bacteria in the intestine.
Mayo Health Care Articles
Mayo Health Care Books
Mayo Health Care