Evidence of Dietary Supplement Efficacy

The Natural Standard is composed of a panel of experts, including medical doctors, pharmacists, and those working in the fields of medicine, nutrition, complementary and alternative therapies, and dietary supplements. The Natural Standard provides a clearinghouse of the vast research performed on various vitamin, mineral, herbal, botanical, and other dietary supplements. The group classifies dietary supplements and their specific uses based on extensive reviews of the scientific literature, and these reports are evaluated by experts and reviewed by their peers. The methods used are based on currently accepted and rigorous scientific standards. Table 4.6 explains this classification system further.

fatty acids such as those found in fish oil are a popular dietary supplement with several purported effects. To evaluate the existing literature on omega-3 fatty acids, the Natural Standard reviewed 252 individual references, most of which were from peer-reviewed journals. Based on the quality (the types of studies available and how many are randomized, controlled trials) and quantity (the number of randomized, controlled trials available) of evidence, the Natural Standard determined that there was "strong scientific evidence" (level A) for the use of omega-3 fatty acids in lowering triglycerides, a component of blood cholesterol. In addition, the group determined that there was "good scientific evidence" (level B) for the use of omega-3 fatty acids (in the form of fish oil) for alleviation of morning stiffness and joint tenderness of rheumatoid arthritis. Table 4.7 lists dietary supplements with strong scientific evidence of a positive effect or of having no effect.