Dietary Suppliments: How Effective Are They?

Written by Vickie Moller  |  23. September 2011

As Americans, our affluence and privilege have afforded us bountiful and varied diets that allow us the liberty of focusing a great deal of our attention on health and wellness in attempts to improve the quality of our lives and increase our longevity.  As a result, each year in the United States billions of dollars of vitamin supplements and nutritional products are sold.

In 2005 a survey conducted by the Natural Marketing Institute, a consulting and market research company specializing in the health and wellness industry, and the Dietary Supplement Education Alliance, a coalition promoting the value of nutritional supplements, found that 85 percent of Americans regularly took one or more dietary supplements.  Most people take them with the hope that they will ward off disease and increase their energy and quality of life.  Some believe that although they regularly consume a substandard diet, their daily compliment of dietary supplements will fulfill their nutritional requirements. 

What, then, exactly is a nutritional supplement?  According to the Institute of Medicine and National Research Council of the National Academies Committee on the Framework for Evaluating the Safety of Dietary Supplements, a dietary supplement is defined as a product that contains a vitamin, mineral, amino acid, or herb, or a dietary substance for use to supplement the diet by increasing the total dietary intake. . .and are intended for ingestion as a capsule, powder, soft gel or gel cap; and not a conventional food or sole item of the meal or the diet.  Dietary supplements come in many forms, including, among others, vitamins, minerals, herbals, sports nutrition products, and meal supplements.  According to the PDR (Physician’s Desk Reference) Family Guide to Nutritional Supplements, they also include the relatively new “neutraceuticals”, which are extracts of foods claimed to have a medicinal effect on human health. 

            Undoubtedly, there exists a vast and growing body of evidence that clearly demonstrates the value and effectiveness of nutritional supplementation.  The Natural Standard, a collaboration of medical doctors, pharmacists and other professionals involved in the fields of nutrition, alternative therapies, and nutritional supplementation, is among the many credible organizations that publish the benefits of nutritional supplements.  After reviewing 252 references regarding the literature on omega-3 fatty acids (mostly from peer-reviewed journals), the group determined that there was ‘strong scientific evidence’ for the use of omega-3 fatty acids in lowering triglycerides, a component of blood cholesterol.  In addition, they concluded that there was ‘good scientific evidence’ for the use of omega-3 fatty acids (in the form of fish oil) for the alleviation of morning stiffness and joint tenderness associated with rheumatoid arthritis.  Their findings, available on www.naturalstandard.com, include a list of scores of dietary supplements, ranging from aloe vera to thiamin and from beta carotene to soy that show strong scientific evidence of a benefit based on at least one randomized controlled trial.

Dr. Daniel G. Amen, M.D., a clinical neuroscientist, psychiatrist, and brain-imaging expert who heads up the widely-known Amen Clinics also touts the value of nutritional supplements, pointing out the significant advances made in research regarding them over the last 20 years.  Dr. Amen cites the following seven foundational reasons why he uses nutritional supplements in his mental health practice:

  • they are often effective in the treatment of mild to moderate mental health problems
  • they are less expensive than pharmaceuticals
  • they have significantly fewer side effects than do pharmaceuticals
  • they are geared to both prevention and treatment of illness
  • patients are not required to reveal to insurance companies that they take them (citing that insurance may be denied to those taking certain psychiatric prescription medications)
  • those who take supplements are more compliant and consistent in their use since ther are fewer side effects than with pharmaceutical medications
  • many supplements are backed by solid research.

Dr. Amen further reminds us that 91 percent of Americans do not eat the recommended five helpings of fruits and vegetables per day and that with the exception of vitamin D, humans do not make their own vitamins and must obtain them from outside sources.

Additionally, in 2002 the American Medical Association changed its long-standing position against the use of vitamin supplementation.  Underscoring its decision to advise that all adults take at least one multivitamin pill each day was the mounting evidence of the benefits of vitamins.  The new guidelines, published in the Journal of the American Medical Association (JAMA), were written by Robert H. Fletcher, MD, MSc, and Kathleen M. Fairfield, MD, DrPH, of Harvard Medical School and the Harvard School of Public Health.  Their findings were based on the review of decades of scientific research regarding the relationship between vitamins and chronic diseases.  In the scientific review article, Fletcher and Fairfield explain, "recent evidence has shown that suboptimal levels of vitamins, even well above those causing deficiency syndromes, are associated with increased risk of chronic diseases including cardiovascular disease, cancer and osteoporosis".

The PDR Family Guide to Nutritional Supplements also concurs that there is little doubt that certain nutritional supplements can provide benefits by boosting the immune system, protecting the heart and relieving a wide variety of ailments. 

While evidence regarding the effectiveness of nutritional supplements continues to mount, there also exists a great deal of conclusive evidence bringing into question their quality and efficacy.  A major concern lies in the fact that dietary supplements comprise such a vast range of different substances and that researchers have basically grouped them into two major categories:  the first comprised of those substances for which evidence exists to benefit health, such as vitamins and minerals and some herbal products, and the second comprised of everything else.  Dr. Jeffrey Blumberg, senior scientist and director of the Antioxidants Laboratory at the Human Nutrition Research Center on Aging at Tufts University contends that “What makes understanding and regulating dietary supplements so complex is that many different substances are lumped together in one group . . . including all of these different substances under one heading is worse than comparing apples with oranges”.

In addition, the Food and Drug Administration has no authority to review dietary supplements for safety or for effectiveness prior to marketing.  As a matter of fact, effectiveness does not enter into the FDA’s regulatory decision-making process at all.  The substantiation of label claims regarding nutritional supplements rests with the manufacturer, and as a result, many nutritional supplements are marketed on the basis of purely theoretical “claims” that can be either true or completely false, leaving consumers at the mercy of “trial and error”.  Either testing has failed to verify benefits or, as in the majority of cases, no tests at all have been conducted to determine efficacy.

Private consumer watchdog groups, such as Natural Products Association (www.npainfo.org), a non-profit organization founded in 1936 in efforts to ensure that consumers have access to high-quality, effective natural products corroborate these facts.  They regularly perform spot checks on nutritional supplements and routinely find that the products they examine contain very little or none of the active ingredients they claim to include.

            Extensive scientific research of some of the most widely-used vitamin supplements also brings into question their efficacy.  For example, in July 1997 the Physicians’ Health Study, one of the largest and longest-running observational cohort studies in America, conducted a randomized, double-blind, placebo-controlled trial (the gold standard of trial procedures among researchers) of beta-carotene, vitamins E and C, and multivitamins in the prevention of cancer, cardiovascular disease and eye disease.  The study continued until December 2007.  The results, presented at the American Heart Association Scientific 2008 Sessions and published online in the Journal of the American Medical Association, showed that neither vitamin E or vitamin C, supplements, commonly believed to help prevent or delay coronary heart disease, had any effect in reducing a combination of nonfatal heart attack, nonfatal stroke, or cardiovascular death after 8 years of treatment.

            In response to these results, Barbara V. Howard, PhD, chair of the American Heart Association Council on Nutrition, reminded us that people don’t eat nutrients, they eat foods.  After rehearsing the benefits of whole foods and sound nutrition, she concluded, “This is the way that we think at this point we have the best evidence that cardiovascular disease can be reduced, and in these hard economic times, maybe we can save some money and not buy these supplements”.

Herbals and botanicals are another category of supplements that are widely used.  However, according to Jenna Hollenstein, author of Understanding Dietary Supplements, scientific evidence supporting the efficacy and safety of herbal and botanical dietary supplements, such as alfalfa, black cohosh, ginger, ginseng, and many others is currently lacking.

These findings offer convincing evidence that we must take individual responsibility for educating ourselves and thoroughly scrutinizing the nutritional supplements that we introduce into our diets.  Taking charge of our health and well-being also includes understanding our vital and complex nutritional needs, considering the fact that many valuable nutrients are available to us from whole foods that we may consume in insufficient amounts or, perhaps, not at all.  Before adding supplements to our diets, we should be certain that we are adequately ingesting a variety of foods—fruits and vegetables, whole grains, lean meats, fish, and dairy products—in moderate, balanced, and calorie-controlled proportions, allowing their whole, unadulterated nutrients to do the life-sustaining work they alone were intended to do.



This Article was Written by Vickie Moller-Pepe.

Some of the information provided in this article has been derived from these sources: PDR Family Guide to Nutritional Supplements, Understanding Dietary Supplements, www.naturalstandard.com, www.npainfo.org.



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