New Lower RDI for Vitamin A

A panel of experts at the National Academy of Sciences recently lowered the amount of vitamin A recommended for men (3000), women (2300) and children (1000-2000 depending on age). They also established an upper limit of 10,000 IU for adults, 5,600 IU for kids 9-13, 3,000 IU for kids 4-8 and 2,000 IU for infants and toddlers. These levels apply only to the form of Vitamin A that is found in animals (retinol) and not to the vitamin A precursors found in plants (beta carotene and other carotenoids) because the body converts only what it needs to retinol.

An excess of beta-carotene from eating lots of carrots, spinach and mangoes may turn your skin yellow-orange but it does not lead to retinol toxicity. There is growing concern that some Americans may be getting too much retinol. Last spring, Metabolife International recalled its ?Diet & Energy Bars? because they contained a toxic dose of retinol (32,500/bar). Some food supplements containing 25,000 IU or more of retinol per pill are still being sold. Vitamin A toxicity has also occurred in people eating a lot of liver. Just 3 ounces of beef liver has over 30,000 IU. Chicken liver has about 14,000 IU in a 3 ounces portion. Cod liver oil is also very high in retinol. Many multivitamins contain 5,000 to 10,000 IU. In addition several popular cereals, nonfat milk and a growing number of other foods are fortified with Vitamin A.Americans are getting too much retinol.The more retinol one consumes and the longer one consumes it, the greater the danger of toxicity. Too much retinol can cause nausea, dry scaly skin, hair loss, and bone pain. In adults, excess retinol can lead to headaches and blurred vision. In babies, vitamin A toxicity can lead to an enlarged liver and a failure to grow. A supplement of as little as 10,000 IU a day in pregnant women can cause birth defects. There is growing scientific evidence that an excessive intake of retinol over many years may weaken bone and contribute to osteoporosis. However, a deficiency of vitamin A remains a major cause of permanent blindness worldwide. Low levels of vitamin A can lead to night blindness and roughening of the skin but both of these resolve quickly with just 3,000 IU daily.My advice: Don?t take supplements with more than the new RDI for vitamin A and don?t overdo it with cereals, nonfat milk, and other foods with added retinol. A little is good but more may be harmful.By Dr. James J. Kenney, PhD, RD, FACN.