|Vitamin A, also called retinol, helps your eyes adjust to light changes when you come in from outside and also helps keep your eyes, skin and mucous membranes moist. Vitamin A mostly comes from animal foods, but some plant-based foods supply beta-carotene, which your body then converts into Vitamin A. It also has antioxidant properties that neutralize free radicals in the body that cause tissue and cellular damage.
Early information from scientific studies suggests that beta-carotene might help people who already have Coronary Artery Disease (CAD). The American Heart Association doesn't recommend taking supplements of beta-carotene until more is known, however.
Nutritionists categorize vitamins by the materials that a vitamin will dissolve in. There are two categories: water-soluble and fat-soluble vitamins. Fat-soluble vitamins—vitamins A, D, E and K—are stored in the fat tissues of the body for a few days to up to six months. If you get too much of a fat-soluble vitamin, it can be stored in your liver and may sometimes cause health problems. Vitamin A is a fat-soluble vitamin.
Some people take mega-doses of fat-soluble vitamins, which can lead to toxicity. Eating a normal diet of foods rich in these vitamins won't cause a problem. Remember, you only need small amounts of any vitamin. In the case of vitamin A, overconsumption has been linked with an increased risk of fractures in postmenopausal women.
Some health problems can make it hard for a person's body to absorb these vitamins. If you have a chronic health condition, ask your doctor about whether your vitamin absorption will be affected.
How Much Vitamin A Is Enough?
It's recommended that women consume 800 mcg and men consume 1000 mcg of vitamin A daily.
Sources of Vitamin A
Top sources of vitamin A include:
- Beef liver
- Egg yolk
- Cheddar cheese
- Fortified milk
Top sources of beta-carotene include:
- Sweet potato
- Spinach and collard greens
Can You Have Too Much or Too Little?
Vitamin A deficiency is rare in the United States, but it can cause night blindness, eye inflammation, diarrhea and other problems. Overconsumption of vitamin A can cause nausea, irritability and blurred vision in its mild form. In addition, the palms of the hands and the bottoms of the feet can turn orange if a person has a high intake of Vitamin A. Vitamin A toxicity can cause growth retardation, hair loss and enlarged spleen and liver in its more severe form. Vitamin A overdose can also cause birth defects and has been linked to increased risk of bone fractures in some people.
If you want to get the most vitamins possible from your food, refrigerate fresh produce, and keep milk and grains away from strong light. Vitamins are easily destroyed and washed out during food preparation and storage. If you take vitamin supplements, store them at room temperature in a dry place that's free of moisture.