The use of dietary supplements continues to increase worldwide. In the US, sales of dietary supplement is reaching $30 billion per year, but their use transcend cultural barriers, and dietary supplement products now can be found virtually anywhere in the world. One reason for the widespread use of dietary supplements is the increasing concern in the general population about diet-related chronic diseases, such as diabetes, arthritis, and cardiovascular diseases. In addition, limited access to preventive health care (particularly in the US) may encourage people to self-medicate, as a means to reduce any perceived risk of disease. Claims on the curative properties of dietary supplements abound, many times based on individual testimonials or unsubstantiated data. Still, most health practitioners are likely to confront the decision of whether to recommend (or to allow) a nutritional supplement, based on their own experience and on the best scientific evidence available.
