FWA, Literature Review

Does Dietary Supplement Consumption Really Promote Health?

Literature Review

In recent years, it would not be wrong to say that dietary supplements have become more and more important role in our society. Billions of them have been sold throughout our world, especially in the United States. A large proportion of Americans strongly believe that regularly taking dietary supplements would help be healthy. Many scientific researches indicate supplements’ ability in reducing risk for certain diseases or other conditions, such as certain cancers, heart disease, osteoporosis, or neural tube defect. However, several evidences argued that taking dietary supplements may not promote health in healthy people; indeed, taking excess amounts of supplements can cause some serious diseases. Until now, the necessary of dietary supplement consumption has still been widely debated.

Among all countries, the United States leads the world in dietary supplement usage with 100.4 million Americans using vitamin and minerals every day and 37.2 million using herbal remedies regularly in 2000 (Prevention Magazine, 2000). Retail and non-retail sales of dietary supplement products across all distribution channels in that year were $17 billion (The Nutrition Business Journal, 2001). Interest in the use of dietary supplements appears to be dramatically growing. In 2004, the Institute of Medicine reported that 18.9 percent or around one in every five Americans had taken one or more dietary supplements. The most prevalent reason consumers use dietary supplements is to improve overall health and general well being (Roper Starch Worldwide, 2001). A large number of scientific researches try to link diets high in some nutrients, such as calcium, beta carotene, vitamin A, C, and E, with a lower risk for certain diseases. Those are a key factor contributing to increased interest in taking supplements.

Kristin Wallace reported in the June 16 issue of the Journal of the National Cancer Institute, 2004 that calcium supplementation may lower risk of advanced colon polyps. She suggested that taking calcium supplement slightly decreased the risk of all types of colorectal polyps, but its effect was greatest for the most advanced colorectal lesions. Another interesting research supported the necessary to supplement calcium regularly is a study in the Archives of Internal Medicine. Dr. Emily Senay referred the research in The Early Show, April25, 2006 to confirm that calcium supplements are useful for bone health and play important role in preventing osteoporosis, the bone-weakening condition, especially in elderly women taking those frequently. The necessity to supplement calcium was also pointed out by several researchers. Robert P. Heaney, MD, of the Osteoporosis Research Center at Creighton University Medical Center in Omaha, Nebraska also highlighted the importance of such supplements at the American Society of Bone and Mineral Research 27th Annual meeting. "You want to tell American women to go to the chalkboard and write 1,000 times, 'I will take my calcium.'" said Heaney. “Americans aren't getting enough calcium from their diets and that is why physicians advise them to take calcium supplements."

About vitamin C supplements, their protective effects on various chronic diseases have also been studied. The First National Health and Nutrition Examination Study (NHANES I) pointed that vitamin C supplement might have preventive effect to cardiovascular disease (CVD). Men and women regularly taking vitamin C about 300 mg/day from supplements and dietary vitamin C had been observed and found that they had a lower risk of death from cardiovascular disease, 42% lower in men and 25% lower in women. Besides, vitamin C’s ability in decreasing lung cancer has been revealed for a long time. Kromhout described in Essential micronutrients in relation to carcinogenesis, 1987 that consuming more than 83 mg of vitamin C daily could lower a risk of lung cancer.

On the contrary, the failure of dietary supplements in preventing diseases has also been widely published. British Medical Journal-BMJ, October1, 2006 demonstrated the failure of calcium supplements to provide long-term strengthening of bones. This research was a review of 19 major studies that involved around 2900 healthy children aged between three and 18 and found that such supplements felt to prevent bone fractures in children. It stated that children taking such supplements had only small improvements in bone density, which were unlikely to reduce fracture risk. Another study published in the Lancet, one of the world largest medical magazines, 2005 surprisingly concluded that calcium supplementation could not help protect older patients at risk for fractures. "There was no evidence that supplementation might be especially useful for specific groups or that true differences could have been obscured by poor compliance," Adrian M. Grant, M.D., and colleagues wrote in the April 28 online issue of The Lancet.

Even though the property of vitamin C as an effective antioxidant has been accepted universally, the failure of the vitamin C effect against oxidation in many patients has been widely reviewed. Joseph P. Gaut, MD, of the Department of Surgery, Washington University, St. Louis, Minnesota and his colleagues demonstrated in the Free Radical Biology and Medicine, 2006 that vitamin C felt to prevent lipids and amino acids from oxidative damage during acute inflammation in mice. This conclusion contradicted the long-held belief that vitamin C supplementation could help protect biological molecule damage from oxidation in animals. In addition, studies of Creagan (1979) and Moertel (1985) published in the New England Journal of Medicine found no differences in outcome between cancer patients receiving high dose of vitamin C, 10 grams per day, orally and those who did not.

Many nutrition researchers still assured that dietary supplements intake might not promote health. In fact, the excess amounts of some dietary supplements can cause serious conditions. Over consumption of calcium can increase amount of calcium in blood, and develop to hypercalcemia, abnormally elevated blood calcium, which dramatically increases the risk of kidney stones. It was found in a large prospective study that women taking supplemental calcium had 20% higher risk of developing kidney stones than those who did not (Gary Curchan and his colleagues, 1997). Nonetheless, a risk of prostate cancer significantly increases in men frequently taking high dose of calcium. A large prospective cohort study in U.S. found that men whose calcium intake was over than 2,000 mg daily had a risk of developing advanced prostate cancer three times higher than those whose calcium consumption was less than 500 mg per day (Giovannucci and his colleagues, 1998).

For the preceding paragraphs, there can be no doubt that the necessity of dietary supplement consumption has still been universally debated. Should we go on taking supplements? Do dietary supplements really promote or improve our health? The answers of these questions and the actions we will act to in the future deal with our consuming behaviors would largely affect our own health. Therefore, it is unavoidable to interest in both benefits and drawbacks of dietary supplements; however, almost all of today advertisements tend to convince us to take supplements by a variety of techniques. Many of them try to refer doctors or researchers to make their products seem reliable. Unfortunately, there is only little evidence that dietary supplements have the effect that they claim. Indeed, some supplements can cause serious damage to a user’s health. What’s about FDA?, the U.S. Food and Drug Administration (FDA) does not check on the safety of dietary supplements before they are sold. The FDA has to wait until it receives reports of problems caused by supplements before it can investigate and ban a dietary supplement (Dr. Steven, MD, and Dr. Jessica, RD, CDE, MPH). Hence, it is our own responsibility to consider and make a decision whether we should take supplements or not. This paper provides some critical evidences and facts about dietary supplements to help consider and remind you not too much believe in such supplement advertisements.