Too much of a good thing - Quick Studies - retinol - Brief Article

TOO much retinol--the kind of vitamin A found in supplements and animal foods like milk and liver--may weaken bones. Women who consumed the highest levels (at least 6,660 IU a day) had nearly double the risk of hip fracture compared with women who consumed the lowest levels (less than 1,600 IU a day).

The findings fit with animal studies, where retinol (or its close cousins) suppresses the osteoblasts, cells that build bone, and stimulates the osteoclasts, cells that break bone down.

The beta-carotene that's found in fruits and vegetables, which the body converts to vitamin A, was not linked to hip fractures. Multivitamins and breaktast cereals were two of the largest sources of retinol, though many brands get some of their vitamin A from beta-carotene.

What to do: If you take a multivitamin, make sure that it contains no more than 4,000 IU of vitamin A retinol (which is also called vitamin A palmitate). Also, make sure that your breakfast cereal has no more than 750 IU of retinol from vitamin A palmitate. That's 15 percent of the Daily Value, or DV. (Total cereal, for example, has 500 IU. That's ten percent of the DV.)

J. Amer. Med. Assoc. 287: 47 2002.

COPYRIGHT 2002 Center for Science in the Public Interest
COPYRIGHT 2002 Gale Group