Are dietary supplements safe? Ask a consumer, manufacturer, distributor, researcher or physician, and most likely there will be five different answers.
- The consumer assumes FDA is monitoring the safety of these products.
- The manufacturer assumes the ingredient supplier has done the necessary tests.
- The distributor assumes the manufacturer has done the same.
- The researcher assumes no tests have been done and sends all products out for independent analysis.
- The physician thinks the products are no more than placebos and are assumed safe.
In general, the use of dietary supplements in the United States has been regarded as safe, thanks to a number of factors. Supplements are used for minor medical conditions, which get better on their own over time, or for maintaining the health of a mostly healthy population. Special demographic groups, like children, the elderly and those with serious diseases, are not the primary consumers of these products; and those who regularly consume dietary supplements are less likely to have a serious medical condition.
Nonetheless, adverse reactions from dietary supplement use can occur for many reasons.
The product can be adulterated, contaminated or substituted. There is the possibility of ingredient toxicity; the product can have pharmacological effects; it can interact with other drugs or supplements; or may be abused.
Most safety data comes from historical use, case reports, clinical trials and pharmacovigilance (adverse event reporting systems). Dietary supplements, however, have much less data available than pharmaceutical products. Fewer published case reports and clinical trials are available, and, more importantly, pharmacovigilance has only recently become an option for supplement safety.
The need for such data has become necessary, and meaningful interpretation of this data is critical. One must be able to determine biological plausibility, incidence, prevalence, relative risk, cost, population, confounding factors and whether the suspected product was viewed and/or tested. The wrong determination can be enough “evidence” to tarnish an ingredient’s reputation, as occurred with kava kava and black cohosh.
