Fat-Soluble Vitamins A, D, E, and K Explained

Learn the Importance of Fat-Soluble Vitamins in Your Diet and Health

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Fat-soluble vitamins are those which disperse and are stored in fat. Vitamins A, D, E, and K are fat-soluble vitamins. Some phytonutrients, such as the carotenoids (e.g. beta-carotene) are also fat-soluble.These nutrients are needed to ensure proper maintenance of tissues as well as normal bodily functions and and growth.

Fat-Soluble Vitamins Explained

Fat-soluble vitamins are stored in the body. Because they can build up over long periods of time, it's possible to develop a toxicity from over-consumption.

This is very unlikely to happen from food consumption (or in the case of Vitamin D, exposure to sun), but could happen by consuming large amounts in "mega" vitamin pills. Consuming fat-containing foods aids in the absorption of fat-soluble vitamins and phytonutrients, however only small amounts of fat are required for this purpose.

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Vitamin A

Vitamin A, also known as retinol, is a fat-soluble vitamin. Vitamin A's most active pro-vitamin form can be found in beta-carotene. Vitamin A is found in foods that come from animal sources, such as fish oils, liver, butter, egg yolks and cream and are called preformed vitamin A, while carotenoids found in fruits and vegetables are called pro-vitamin A because they are turned into vitamin A in the body (although some people's bodies are better at doing this than others). People with diseases that leave them with fat malabsorption, i.e. celiac disease, Crohn’s disease, pancreatic disorders, may become vitamin A deficient.

Vitamin A has interactions with iron and zinc and deficiencies in these minerals can effect vitamin A metabolism in the body.

Vitamin K

Vitamin K, also known as phylloquinone, assists with the body's normal blood clotting as well as the transport of calcium. Americans get their vitamin K through green leafy vegetables primarily.

While it is hard to digest, like other fat soluble vitamins, eating green leafy vegetables like spinach with fat, such as butter or olive oil can increase the uptake of the vitamin by more than 3 times. Vitamin K is indicated in bone health so keep eating those leafy greens.  

Vitamin E

Interestingly, Americans top sources of vitamin E comes from some not-so-nutritious foods such as, pizza, chili, spaghetti sauce and french fries. Vitamin E comes from tocopherols. Healthier sources of vitamin E include tomatoes, eggs, and nuts and seeds.

Vitamin D

Vitamin D, called calciferol, is found only in a few foods that Americans don't eat very well including, fish-liver oils, fatty fish, mushrooms, egg yolks and liver. Although daily exposure to the sun is sufficient to maintain healthy levels of vitamin D, most Americans get most of theirs from fortified foods such as dairy products and other fortified breakfast foods and orange juice. Vitamin D helps the body absorb calcium and phosphorous by acting as a hormone in the small intestine.

Carotenoids

Carotenoids are red and yellow pigments found in fruits and vegetables that are also fat-soluble nutrients. Americans consume between 40 and 50 of the over 700 available in nature. Some of the major sources of carotenoids are orange-colored fruits and vegetables such as mangoes, carrots, and pumpkins.

The Bottom Line

Fat-soluble vitamins are a reminder that dietary fat is an essential part of our diets and is necessary for our body's to absorb certain vitamins and nutrients. By making sure you eat an adequate amount of fat, leafy greens, fruits and vegetables and meats, you will set yourself up to absorb fat-soluble vitamins without fail.

Source

Centers for Disease Control. Nutrition Report: Fat-Soluble Vitamins and Nutrients. Accessed 2016

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