While there is a great deal of evidence to indicate that dietary supplements help in preventing and treating states of nutrient deficiency, there is much less evidence about their usefulness in preventing or treating other diseases. Natural products such as herbal medicines or botanicals are often sold as dietary supplements and are readily available to consumers; however, there is a lot we don't know about the safety of many of these products, in part because a manufacturer does not have to prove the safety and effectiveness of a dietary supplement before it is available to the public.Two of the main safety concerns for dietary supplements are
- The possibilities of drug interactions—for example, research has shown that St. John's wort interacts with drugs such as antidepressants in ways that can interfere with their intended effects
- The possibilities of product contamination—supplements have been found to contain hidden prescription drugs or other compounds, particularly in dietary supplements marketed for weight loss, sexual health including erectile dysfunction, and athletic performance or body-building.
