An estimated 100 million Americans spend $6.5 billion a year on vitamin and mineral supplements. But these consumers are buying mostly unregulated substances that may help, may harm or may simply have no effect at all.

In the average grocery store, the vitamin-buying consumer faces a wall of possibilities. To add to the confusion, the labels on these bottles provide few clues that the products can be harmful as well as helpful. They do not mention this possibility because the Food and Drug Administration considers vitamins and minerals as “dietary supplements”. As a result, no testing for safety or efficiency–or even for whether the supplements contain what the bottle says they contain–is required before vitamins are put on the shelves.

Even the experts in nutrition have trouble giving consistent information about vitamins and minerals because there is a lack of good long-term studies on them. The government can provide a bewildering volume of standards which it is in the process of revising. “No rational person can understand this stuff,” says Dr. Marion Nestle, chairman of the department of nutrition and food studies at New York University. “All the different numbers are almost guaranteed to make the situation more confusing rather than less.”

The current boom in the vitamin business began in October, 1994, when Congress passed the Dietary Supplement Health and Education Act, which basically keeps the FDA’s hands off vitamins and mineral supplements unless something goes wrong. Stocks that had dropped in 1994 surged 70 percent in 1995, 57 percent in 1995 and 42 percent in the first half of 1997, wildly outperforming the overall market.

Vitamin suppliers fought hard for this profit margin. The FDA had been planning to apply existing regulations for items like drugs to vitamins, minerals, herbal preparations and other supplements. Those rules would have prevented manufacturers from making health claims of any sort for any supplements without agency approval. The vitamin industry responded with fierce lobbying, aided by a letter-writing campaign by consumers who feared that government rules would limit their access to all kinds of supplements. The 1994 law was a compromise–labels on vitamin and mineral products cannot make claims that a product cures a disease or gives a specific health effect without special FDA approval. However, the law does allow general statements on the label about a vitamin or mineral’s function in the body.

The lack of specific claims has not stopped people from assuming vitamins offer extraordinary healing benefits. Based on meager evidence and word-of-mouth, consumers buy the supplements and hope that a nutrient’s normal role is magnified and the vitamin can work as a miracle cure for terminal diseases such as cancer, or a magic wand tonic to a poor diet. The vitamin industry has profited handsomely by such unproven wishful thinking.

Faced with the growing need for more research, the National Institutes of Health established, at the request of Congress, an Office of Dietary Supplements in November 1995. Their research will take some time. Meanwhile, caveat emptor! (Buyer beware)