A non-profit organization dedicated to the natural products industry has disputed the results of a study measuring the efficacy of multivitamins in cancer prevention.
The criticized study – conducted by researchers from the Fred Hutchinson Cancer Research Center – suggested that long-term multivitamin use had no impact on the risk of common cancers, cardiovascular disease and general mortality in postmenopausal women.
However, the study failed to take into account important dietary factors, according to the Natural Products Association.
"While cohort and observational studies like these can be important, they in no way constitute convincing or conclusive evidence," says Dr Daniel Fabricant, vice president of scientific and regulatory affairs for the Natural Products Association.
He complains that the authors arbitrarily assigned categories to different supplement types. He also says they did not account for nutrient intake through the diet, failing to establish a baseline against which to make comparisons.
Fabricant further criticized the authors for being apparently unaware of how supplements are regulated and how the FDA authorizes health claims.
"To suggest that taking vitamins and minerals with a demonstrated health benefit is unnecessary sends the wrong public health message," he says.
Some 180 million Americans take dietary supplements to make up for inadequate diets and maintain and improve health.