Mad-cow disease, formally known as bovine spongiform encephalopathy, or BSE, and its human form, new-variant Creutzfeldt- Jakob disease, haven't been linked to dietary supplements. Industry officials consider the possibility of contracting the disease through supplements remote. But they worry that the faintest mention of the fatal, brain-wasting illness--detected in cattle in nine European countries--might cause consumers to swear off supplements.

Instead, supplement makers have been lobbying the FDA to promulgate so-called good manufacturing practices, which would, among other things, regulate cleanliness of supplement factories and the potency and stability of ingredients. The FDA has called adoption of such standards a priority, one that is likely to draw heightened attention because of mad-cow concerns. In a videotaped address to a Consumer Health Products Assn. convention in Anaheim on Jan. 31, Joseph A. Levitt, director of the FDA unit that regulates supplements, said he is "very concerned there are no regulations at FDA" on BSE. "The industry needs regulations," he said. The FDA planned to move the issue "quickly to the front burner."

The FDA has been urging manufacturers and importers of dietary supplements to avoid products from countries where BSE has been detected. On Nov. 14, it sent a letter to the industry listing 21 bovine tissues suspected of harboring the disease. Of highest concern are supplements made from the brain and spinal cord. The industry believes many of the so-called glandular products, which account for about 1% of supplement sales, are made from domestic cattle or animals from Argentina and China.