Vitamin A Sources and Functions
They all work together
All of the vitamins work together to keep you healthy and feeling good. Here is a summary of the role of Vitamin A, a fat-soluble vitamin, in your good health.
|What it does||Promotes healthy skin, eyes, membranes; Functions in reproduction and growth|
|Daily needs|| [Infants*: 400-500 µg or 1,333-1667 IU] |
[Children†: 300-900 µg or 1,000-3,000 IU]
[Men: 900 µg or 3000 IU ]
[Women: 700 µg or 2333 IU]
[Pregnant: 770µg or 2567 IU]
[Lactating: 1300 µg or 4333 IU]
|Not enough||Vision problems, including impaired night vision and blindness, skin problems, poor immunity to infectious diseases|
|Too Much||Nausea, Headache, Fatigue, Cerebral edema, Bulging fontanel in infants (Upper Limit established by USDA is 3,000 µg or 10,000 IU)|
|Foods||Deep yellow and orange fruits and vegetables, Fortified milk, Butter, Liver, Eggs, Cheese, Dark Green Leafy Vegetables|
*The lower value is for infants up to 6 mos., the higher value is for infants up to a year old.
† The first value is for children 1-3 with the amount increasing until age 18.# Vitamin A RDA is expressed as “retinol activity equivalents, “RAE,” with 1 µg of retinol is 1 RAE. The amounts are also given is International Units (IU), since many supplements still describe the Vitamin A content in that way.
Beta-carotene is a precursor to Vitamin A. That is, your body can convert beta-carotene to Vitamin A. Beta-carotene is the phytonutrient that is responsible for the deep orange color of vegetables such as carrots, winter squash, sweet potatoes.
In general, people who live in developed countries like the United States get enough Vitamin A. However, those suffering from eating disorders or living in poverty may not be eating enough food to get sufficient Vitamin A in their diet. In underdeveloped countries Vitamin A deficiency is a serious problem and a major cause of blindness and disease.
Most people have heard that Vitamin A (“Eat your carrots, Doc!”) is good for your vision. Many even know that Vitamin A is good for your skin. (Thus, the face creams that contain “retinol,” a form of Vitamin A.)
Did you know that Vitamin A is also an important factor in immunity? It plays several vital roles in protecting you from viruses and other infectious diseases.
Eat colorful fruits and vegetables
It is the dark green and deep yellow and orange vegetables that are rich sources of Vitamin A.
Animal sources of Vitamin A include:
Whole or fortified milk
There are always exceptions to the rule
Corn, although it is yellow, is not a good source of Vitamin A, and iceberg lettuce and cabbage, although green, are not the deep green foods that are rich in Vitamin A. Watermelon is a decent source, although it is not yellow, orange or green!
Caveat for Vitamin A sources and functions: Since Vitamin A is a fat-soluble Vitamin, the body can store it in your body fat. The good news is that this means you have a supply of Vitamin A on hand, should your diet fail you.
However, be aware that all of the fat-soluble vitamins can be toxic in large doses, because the excess is not excreted. Toxicity is less likely to occur if you get your Vitamin A from foods, although there is some evidence that eating too much liver can lead to a build up of Vitamin A.
It is always best to get your vitamins from fresh, whole foods whenever possible. If you decide to take a supplement, be aware of the amount of Vitamin A that it contains.