Nutritional Supplements: Too Much is Not a Good Thing
While the risk of adverse affects is relatively low, new research concludes that large doses can damage eyes.
By Karen Rodemich, Managing Editor

Most Americans equate nutritional supplements and herbs with a healthy lifestyle. Yet according to new research by Frederick T. Fraunfelder, M.D., some of these �healthy choices� have the potential to cause serious eye-related side effects when users don�t follow the proper dosage.

Big sellers such as ginkgo biloba, licorice and Echinacea (taken for general health) and eyebright and chamomile (taken for eye health) have caused conjunctivitis and even eye hemorrhages, toxic maculopathy and intracranial hypertension.

�The risk mainly is when toxic doses are taken,� says Dr. Fraunfelder. �When recommended doses are taken I have no evidence ocular side effects occur.�

In his research, Dr. Fraunfelder, a professor of the Department of Ophthalmology at the Oregon Health and Science University�s Casey Eye Institute, found hundreds of reports of eye problems caused by nutritional supplements and herbs. Most of the reports � found in documents to the World Health Organization, the U.S. Food and Drug Administration and the National Registry of Drug-Induced Ocular Side Effects, as well as medical literature � were related to supplements/vitamins to support general health, not to enhance visual health.

Dr. Fraunfelder thinks the major offenders among supplements are excessive amounts of vitamin A and niacin. When asked what kinds of adverse eye problems typically occur with the use of supplements and vitamins, Dr. Fraunfelder replied, �Nothing is typical, as every agent works in a different way. I would say irritative conjunctivitis is common though, as we secrete many drugs in our tears.�

Better safe than sorry

Although the risk of a supplement/vitamin-related side effect is small for someone in good health, Dr. Fraunfelder�s findings stress the importance of discussing the use of herbs, vitamins and nutritional supplements with patients. Says Dr. Fraunfelder, �Doctors need to know and patients need to tell their doctors what herbal products they take.� Ask that patients inform you when they begin taking any of these so that you may examine their eyes before use and monitor them during use. And of course, stress that to patients that they follow the recommended dosage.

You can read Dr. Fraunfelder�s findings in the October issue of the American Journal of Ophthalmology.