Fat Soluble Vitamins
Fat soluble vitamins are usually found in foods that contains fats or oils, and your body stores them in the liver and fatty tissues. This means you don't necessarily have to take them every day, but they can also be toxic if you build up a great supply.
Vitamin A
There are two types of vitamin A. Preformed vitamin A, or retinol comes from animal sources. Provitamin A, or carotenoid is found in colorful plant sources.
There are many types of carotenoids, and the most common found in foods is beta-carotene. Beta-carotene is changed into retinol in your body.
Vitamin A is used by the body for vision, bone growth, and cell division and cell differentiation. It also helps regulate the immune system, and promotes healthy surface lining of eyes, digestive tract,respiratory tract, urinary, intestinal tracts, skin and mucous membranes.
Foods high in retinol
- liver
- milk
- cheddar cheese
- whole eggs
Plant sources high in beta-carotene
- carrots
- spinach
- kale
- cantalope
- apricots
- papaya
- mango
- oatmeal
- peas
- tomato juice
Vitamin A is measured in micrograms (µg). One µg retinol = 12 µg beta-carotene.See your daily requirement for Vitamin A.
Vitamin D
Vitamin D is also known as cholecalciferol or ergocalciferol.
There are very few foods that contain this vitamin naturally, although it is added to some foods. The wonderful thing about Vitamin D is that it can be synthesized by the skin in the presence of ultraviolet light.
How much Vitamin D your skin can make depends on a whole bunch of factors such as how far north you live, whether you are wearing sunscreen, smog in the air, season, how much melanin your skin contains, and how much of your body is covered by clothes. For example, if you live around 42° north latitude (Boston), don't plan on synthesizing any Vitamin D from November through February.
As you go further north the time period is longer. It's very difficult to say how long you need to be in the sun to produce Vitamin D, because there are so many factors. However, some studies have shown that 5-30 minutes of sun on the face, arms, legs or back, in the middle of the day, without sunscreen, should give you enough vitamin D.
If you live in a northern climate, wear sunscreen, or don't expose your skin to the sun, try to make sure you are getting Vitamin D in your diet or use a supplement.
You must have Vitamin D present to absorb calcium in the gut, so it helps with bone growth and prevents osteoporosis, and rickets (a softening of the bones). Vitamin D also helps the neuromuscular system and the immune system, and reduces inflammation.
Some foods that contain Vitamin D
- flesh of fish
- fish liver oil
Foods with smaller amounts of Vitamin D
- beef liver
- cheese
- egg yolks
Foods fortified with Vitamin D
- milk
- some brands of cereal
- some brands of orange juice
- some brands of yogurt
- some brands of margarine
Vitamin D is measured in micrograms (µg). If you see it labeled in IUs, one µg = 40 IUs. See your daily requirement for Vitamin D.
Vitamin E
Vitamin E exists in eight different forms, but the most common form found in the diet is alpha-tocopherol. Vitamin E deficiency usually only occurs in people who cannot absorb fat, people with a genetic abnormality related to Vitamin E, or very low birth weight infants.
Vitamin E is an antioxidant which can help protect your body against the effects of free radicals. Free radicals are produced during the metabolism of your food, and can damage cells and lead to cancer or heart disease. Studies are underway to see whether taking extra Vitamin E can help protect against these diseases, but so far nothing has been conclusive. Studies are also being done to see whether Vitamin E can prevent or delay the growth of cataracts. Vitamin E has been shown to help with immune function and repair of DNA.
Good sources of Vitamin E
- wheat germ oil
- nuts
- vegetable oils
- leafy green vegetables
- broccoli
- kiwi
- mangos
- many cereals are fortified with Vitamin E
Vitamin E comes from plant sources, especially oils. If you have a very low fat diet you may not be getting as much Vitamin E as you need.
Vitamin E is measured in milligrams (mg). See your daily requirement for Vitamin E.
Vitamin K
There are three forms of Vitamin K, but the most common form found in our diets is K1, or phylloquinone. Phylloquinone is synthesized by plants. Vitamin K2, or menaquinone, is formed by natural bacteria in the intestines and can also be found in chicken egg yolk, butter, cow liver, certain cheeses and fermented soybean products. Vitamin K3, or menadione, is a synthetic form of the vitamin.
Vitamin K's main function in the body is to regulate blood clotting. In fact, the name comes from the German word "koagulation". Vitamin K is also important for bone health, and can reduce the risk of osteoporosis and fractures.
Good sources of Vitamin K
- broccoli
- Brussels sprouts
- cabbage
- cauliflower
- kale
- spinach
- soybeans
- cows milk and foods made with soy products are also excellent sources
Most vitamin K deficiencies are because of poor absorbtion of the vitamin in the intestines, rather than not getting enough in the diet. See your daily requirement for Vitamin K.