Taking enough vitamin A is important for healthy skin and hair, good vision, and an effective immune system, but as CBS 2's Paul Moniz reports, concerns over the vitamin's toxicity have prompted the government to issue new guidelines that lower its recommended daily allowance (RDA).
The Institute of Medicine, which advises the Food and Drug Administration, lowered the vitamin A RDA from 5,000 International Units (IU) to 3,000 IU for men and to 2,300 IU for women.
Women considering getting pregnant need to be especially careful. Studies have shown that 15,000 IU of vitamin A causes birth defects such as cleft lip, cleft palette, an enlarged head, and major heart defects. In adults, higher doses have resulted in liver damage.
Hepatologist Dr. Mark Russo says taking too much vitamin A is completely avoidable.
"Most Americans, with few exceptions, get more than enough vitamin A in their diet," he says.
Vitamin A is found in everything from milk, meat, and fish to fortified cereals and dark-colored fruits and vegetables such as broccoli and carrots.
Dr. Russo says if you eat healthily, you'll have no problem meeting your daily requirement, but if you take vitamin supplements, you can easily be over the limit.
Dr. Russo says taking high levels over long periods of time can cause a normally smooth liver to become diseased, creating nodules and scar tissue that prevent it from making life-sustaining protein and from absorbing cholesterol.
"You can get increased pressure in the liver, blood can back up, and you can have problems with fluids leaking into your belly," he explains.
Symptoms of vitamin A toxicity include pain in the bones, pain in the upper right side of chest, pain where the liver is located, hair loss, and fever.
The good news is most liver damage is reversible in adults so if caught early and supplement use is discontinued, you can remain healthy.
If you do take a supplement, read the label carefully. A good choice is a multivitamin that has 5,000 IUs of vitamin A or less. And when you get your yearly physical, have a blood test to check your liver enzymes.
It is possible to get too much vitamin A from foods alone. The vitamin A in animal sources is six times more potent than that in vegetables.
Vegetables contain beta-carotene, which is in the vitamin A family but considered safer.
The average carrot contains twice the recommended daily allowance of vitamin A and it's true that your skin can turn orange if you eat too many carrots. But the color fades if you stop.
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