Epidemiologic or observational studies often indicate the positive effects of nutrient and biological substances such as vitamins C, D and E and Selenium and Magnesium, but large, double-blind trials do not confirm the benefit. The reason for this discrepancy was discussed in an article in Family Practice News. Dr. Paul Coates, director of the NIH Office of Dietary Supplements acknowledged that researchers might be designing the trials wrong, expecting nutrients to act like drugs (that block actions of the body rather than enhance normal function). At a meeting sponsored by the Scripps Center for Integrative Medicine, Dr. Jeffrey Bland pointed out that nutrients exert subtle, nonspecific effects on multiple pathways, creating many variables that are impossible to study with controlled clinical trials, whose purpose is to limit variables. Certainly, integrative physicians see the positive benefits of nutrient therapy every day, and there is no doubt that nutrients are much safer and cheaper than prescription drugs.
See Family Practice News (click here), February 1, 2010, p. 55.