Vitamins and other dietary supplements are thinly regulated in the U.S. How safe are they? In my last article I examined safety issues related to multivitamins. Now, I'll look at some surprising--and scary--facts on adverse reactions from the wide range of other dietary supplements people take.

Supplements have been deemed generally safe in a 1994 bill passed by Congress, but evidence has been building that some of these substances can cause injury or death--and that children may face the biggest risk. An article in the New York Times article points out that more than 20 years of statistics by the American Association of Poison Control Centers reveals a more than nine-fold increase in reports due to the use of vitamins, supplements, and other substances such as essential oils (which are not classified as a dietary supplement but are sold widely in supplement stores).

* In 2005 there were more than 125,000 incidents reported due to vitamins, supplements, herbs, and other substances, with 27 deaths. But as the article indicates, the actual number of deaths could be much higher than the 230 reported in the period from 1983 to 2004. The article quotes an unpublished study prepared for the FDA as indicating that "less than one percent of serious adverse events caused by dietary supplements is reported to the FDA."

* Ordinary vitamins were the supplements that were linked to the most reactions in 2005. According to the poison control centers there were 62,446 reports and one death due to vitamins; they accounted for almost half of all report received.
* Minerals were linked to about half the number or reports as vitamins, but also 13 deaths.
* Herbs accounted for fewer than 24,000 total reports but also 13 deaths.
* Melatonin and homeopathic products were the herbs and specialty products that led to the most reports. The poison centers received 2,001 reports of reactions to melatonin, which is marketed as aiding sleep, including 535 hospitalizations and four deaths.
* St. John's wort, marketed as a natural anti-depressant, represented 203 reports of adverse reaction in 2005, including 79 hospitalizations and one death.
* Glucosamine, marketed as a supplement for joint health, linked to 813 adverse reactions including 108 hospitalizations, and one death.
* Echinacea, taken as a remedy to prevent or shorten the duration of the common cold, was linked to 483 adverse reactions, including 55 hospitalizations (one of which was considered life threatening).

The youngest victims were the most frequent sufferers. The Times notes that "Injuries to children under six account for nearly three-quarters of all reports of adverse reactions to dietary supplements, according to the poison centers." What's more, although the article reports that leading medical groups don't recommend dietary supplements to otherwise healthy children, an analysis of a study of maternal and infant health done 10 years ago found that a little over half of parents of preschool children gave their kids a vitamin or mineral supplement.

These facts and figures shouldn't scare anyone from avoiding dietary supplements altogether. But we all need to be aware of what substances we're taking into our bodies and what effects they may have on us, just as many of us do now with food.

Before starting any supplement it's smart to ask your doctor about it to see if it might be unwise for you or may interact with any drugs or supplements you're currently taking. And let your doctor know about your diet habits so he or she is aware of how much vitamin or mineral content you're getting from your diet, so you can avoid excessive (and potentially harmful) intake.