Types Of Vitamin A Sources

Vitamin A is a fat-soluble vitamin that is essential to everyday health. Not only does adequate vitamin A intake play an integral role in bodily growth and tissue healing, but it also helps support the immune system, skin health and eyesight. There are two forms of vitamin A available from dietary sources: preformed vitamin A, which is found in animal products, and provitamin A, which is found in produce.

Animals

Preformed vitamin A, also known as retinol, is found in highest concentrations in animals and animal products. According to the National Institute of Health's Office of Dietary Supplements, liver from chicken or beef is the most highly concentrated source of retinol. Supplemental vitamin A is usually sourced from fish liver oil, which is also a reliable dietary source. Egg yolks and milk products such as whole milk, cream and butter also contain vitamin A.

Vegetables

Provitamin A, also known as beta carotene, is the double molecule form of retinol. This version of the vitamin is converted to retinol within the body. Vegetables that are yellow and orange in color are the highest in vitamin A. Carrots, pumpkins and yams are all in this category. Dr. Elson Haas states in his book ''Staying Healthy With Nutrition'' that two medium carrots would provide enough vitamin A for an average adult's entire day. Alternatively, leafy greens such as lettuce, spinach and kale are also good sources of vitamin A.

Fruits

Similar to vegetables, fruits that are valuable sources of vitamin A are yellow, orange and red. These include apricots, cherries, mangoes and peaches. The edible skins of these fruits contain higher amounts of vitamins than the flesh.

Supplements

Vitamin A supplements are available for those who either do not eat the foods mentioned above or need to increase their intake of the substance because of an inability to absorb it well. Vitamin A is available in multivitamin tablets and as pure-form softgels. Since the vitamin is a fat-soluble substance, supplements could be taken with fat-containing foods to help increase absorption. However, it is important to adhere to the proper dosage guidelines, as consuming too much vitamin A can be toxic. Too much of the beta-carotene form of vitamin A can cause skin to appear yellow, while too much of the retinol form of vitamin A can cause mild headaches, nausea, dizziness, abdominal pain and hair loss.