Vitamin A: The Real Deal
Why We Need Vitamin A
Vitamin A is necessary for healthy surface linings of the nose, throat, lungs and intestines.
Other key functions of this vitamin include:
Promotes healthy development of bones and teeth
Aids in proper wound healing
Increases resistance to infection
Some experts also say that vitamin A may help prevent some cancers and deter night blindness.
Food Sources of Vitamin A
Vitamin A in our diets comes from both animal and plant sources. Vitamin A found in food from animal sources is called preformed vitamin A, also called retinoids. Rich animal sources of vitamin A include: - Liver and other organ meats
- Fish
- Egg yolks
- Milk and Cream
- Butter
Vitamin A that is found in plants is called provitamin A, also known as carotenoids. Carotenoids are what give yellow, red and orange fruit and veggies their color. Beta-carotene is the most potent of the carotenoids, and also acts as a powerful antioxidant in the body. Plant sources of vitamin A include: - Orange and yellow vegetables and fruits
- Dark green leafy vegetables
How Much Vitamin A Do We Need?
Current RDAs (recommended daily allowances) are as follows:
- 1000 micrograms daily for men
- 800 micrograms daily for women
Those at Risk for a Deficiency
Though vitamin A deficiency is rare in most developed countries, it is not unheard of. Individuals most at risk include:
- Persons following very low-fat diets
- Those who have fat absorption problems due to illness or recent surgical procedures
- Persons whose diets are deficient in protein or zinc
- Individuals who regularly make poor food choices
Can We Get Too Much Vitamin A?
Yes, preformed vitamin A can be toxic in high doses. As a rule, most animal foods don't contain exorbitant amounts of preformed vitamin A.
Supplements are most often the culprits when toxicity issues become a problem.
There are exceptions to every rule, of course. For instance, 3 ounces of polar bear liver is estimated to have about 60,000 micrograms of preformed vitamin A.
That's 60 times the RDA for adult males! So, if you happen to be a fan of polar bear liver--BEWARE!
Symptoms of vitamin A toxicity: - nausea or vomiting
- headache, dizziness or blurred vision
- lack of muscle coordination
- weight loss
- muscle and joint pain
- bone abnormalities
- liver damage
- dry scaly lips
- skin rashes
Please note that preformed vitamin A toxicity can occur with repeated doses of just 10 times the RDA.However, provitamin A, found in plant foods, is non-toxic. Experts say this is because our bodies decrease the absorption of carotenoids when we consume them in high doses. So if you plan on supplementing with vitamin A, please get the advice of a trusted medical professional first. Better to be safe than sorry. To Your Health!
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