-Reminds Consumers of Scientific Basis for Safety and Benefits of Vitamins E and C-
WASHINGTON, D.C., The Council for Responsible Nutrition (CRN), one of the dietary supplement industry’s leading trade associations, today responded to the conclusions drawn by the authors of the Women’s Angiographic Vitamin and Estrogen (WAVE) Trial study as being “an exaggerated recommendation based on inconclusive data.”
CRN noted that careful analysis of the study reveals the study showed no effects beyond random variations in response and that the researchers based their conclusions on statistically insignificant data. “In fact, the actual data showed no difference in artery blockage between the antioxidant group and the control group, even after the researchers arbitrarily created ‘worst-case’ numerical values to fill missing data points,” stated John Hathcock, Ph.D., vice president, nutritional and regulatory science, CRN. “Even those statistics that would appear to be significant are, in actuality, the exact pattern that would randomly occur if no treatments had been administered, and as the authors have stated, this could be a ‘chance finding.’”
Further scrutiny exposes flaws in the study’s design. For example, the study groups were not stratified to assure that all the treatment groups were similar with respect to the degree of coronary artery blockage. In addition, the authors concede that their study was powered only to detect the degree of blockage of the arteries, not the differences in clinical outcomes. Yet much of their discussion focuses on comparisons of clinical outcomes.
The authors of the WAVE study asserted that the results of the Heart Protection Study (HPS) provided support to their conclusions by identifying “a trend toward an increase in mortality” in the vitamin group. However, the authors of the HPS actually reported “no significant differences” in mortality. (Lancet 2002; 360:23-33.)
Dr. Hathcock noted that there is broad scientific consensus that dietary supplements of vitamins E and C are safe in the general population. “It is the cumulative knowledge, or the weight of the overall evidence, that provides health care professionals and consumers with the best scientific guidance. Over the past 25 years, more than 20 studies involving more than 80,000 people have been conducted on vitamins E and C, and on balance these are overwhelmingly safe nutrients.”
The WAVE study should not be considered “the final word,” said Dr. Hathcock who pointed out that another secondary prevention trial of antioxidant vitamins and cardiovascular disease (CVD) in women has been going on for over seven years. The Women’s Antioxidant and Cardiovascular Study (WACS), being conducted by Harvard Medical School and funded by the National Heart, Lung and Blood Institute, involves a larger, but similar, study population to WAVE. The randomized, double-blind, placebo-controlled trial is studying the balance of benefits and risks of vitamins E and C, and beta-carotene, among 8000 women with preexisting CVD.
The Institute of Medicine (IOM) recently established Tolerable Upper Intake Levels (UL) for daily intake for vitamin E and vitamin C, based on an exhaustive review of the medical scientific literature, and set upper safe levels at 1000 mg for vitamin E and 2000 mg for vitamin C.
Vitamins E and C are essential nutrients required for maintenance of health. Vitamin E has potential benefits for vision, Alzheimer’s disease, counteracting free radicals that may play a role in fighting cancers, and reducing the risk of coronary disease. Vitamin C is believed to promote a healthy immune system and may also be beneficial in preventing free radical damage potentially leading to diseases such as cancer.
According to statistics from a 2001 Gallup Study, over 100 million American adults annually take vitamins E and C in dietary supplement form, either in single nutrient supplements or in multivitamins.