Dietary Supplements
Most CAM practitioners and many conventional medical practitioners agree that food sources are the best way to obtain nutrients. They do, however, allow that it is impossible for some people to get all the nutrients they need, or sufficient quantities of specific vitamins or minerals, from their daily diets. For example, many researchers and nutritionists feel that the diets of the majority of Americans do not contain enough chromium and most women do not consume adequate amounts of iron. Further, the CAM principle of treating each patient as an individual with unique physiological and biochemical needs suggests that some individuals may need more of specific nutrients than others.
Advocates of dietary supplements feel that the recommended dietary allowances (RDAs) are too low for some vitamins and minerals, and they observe that it is difficult to obtain higher than the RDA of certain vitamins without also consuming an excess of fat and calories. An example of this dilemma is vitamin E, an antioxidant found in high-fat vegetable and seed oils. Dr. Pelletier in The Best Alternative Medicine points out that for men to get the RDA (fifteen IU [international units]) of vitamin E, they would have to eat "248 slices of whole wheat bread, sixteen dozen eggs, or twenty pounds of bacon." Several studies suggest that far higher doses—twenty to thirty times greater than the RDA—may protect against heart disease or some cancers, but to obtain such doses from diet alone is impossible.
Whether to prescribe diets supplemented with vitamin E is one of many questions about this particular issue. Another concern is the form of vitamin E available—supplements contain only alpha tocopherol instead of the variety of tocopherols available in foods. Is it better to take higher doses of one form of vitamin E at the risk of losing other, perhaps equally valuable forms of vitamin E? Critics of dietary supplements use this question to support their view that people should attempt to obtain as many needed nutrients from food sources as possible, without relying on dietary supplements. Further, there is no consensus about dosages higher than the RDA, although it is known that some vitamins and minerals, such as vitamins A and E and chromium, are toxic in high doses. For example, more than four hundred IU of vitamin E taken daily may increase the risk of stroke, and high doses of vitamin E are generally not advised for people taking medications to reduce blood clotting, such as Coumadin.
Unlike drugs, dietary supplements do not need to be approved by the Food and Drug Administration (FDA) and therefore go to market with far less testing and scrutiny. This has caused debate and may lead to the ultimate FDA banning of certain supplements, as in the case of the herb ephedra, a dietary supplement used for weight loss that was taken off the market in 2004 after it was linked to 155 deaths and dozens of heart attacks and strokes.
USE OF DIETARY SUPPLEMENTS
According to the Natural Marketing Institute (NMI) 2005 Dietary Supplement Consumer Insight Report (Harleysville, PA), based on research from more than twelve thousand U.S. consumer households, Americans are most likely to use supplements to prevent the following diseases and conditions:
- Heart disease (77%)
- Vision problems (75%)
- Obesity/overweight (72%)
- Arthritis/joint disease (72%)
- High cholesterol (71%)
- High blood pressure (68%)
- Memory/concentration problems (66%)
- Diabetes (60%)
The NHIS found that nearly one-fifth (18.9%) of survey respondents used natural products. (See Figure 9.7.) The most frequently used natural product was echinacea (40.3%), followed by ginseng (24.1%), ginkgo biloba (21.1%), garlic supplements (19.9%), glucosamine (14.9%), and St. John's wort (12%). (See Figure 9.8.)
ARE DIETARY SUPPLEMENTS EFFECTIVE?
Many dietary supplements have undergone rigorous testing to determine whether they are effective for the conditions they claim to address. For example, Vincent Morelli and Roger Zoorob in "Alternative Therapies: Part I. Depression, Diabetes, Obesity" (American Family Physician, September 1, 2000) detailed studies comparing dietary supplements to placebos. St. John's wort (Hypericum perforatum) has been shown to help relieve symptoms of depression in persons suffering from mild or moderate, but not severe, depression. Similarly, in some studies, S-Adenosylmethionine (also known as SAMe), has been shown to be better than placebo in the treatment of depression.
Recent research has, however, questioned the efficacy of several popular dietary supplements. The combination of glucosamine (thought to play a role in cartilage formation) and chondroitin (which helps give cartilage elasticity, taken as a supplement to relieve arthritis pain) was found to be no more effective than a placebo. Elizabeth Agnvall in "Joint Dispute" (Washington Post, November 22, 2005) discusses the preliminary results of the NIH-sponsored Glucosamine/Chondroitin Arthritis Intervention Trial (GAIT), which found that among persons with moderate to severe arthritis the supplement combination was somewhat more effective but cautioned
FIGURE 9.8 Top 10 natural products, 2002
Similarly, Ronald B. Turner et al in "Ineffectiveness of Echinacea for Prevention of Experimental Rhinovirus Colds" (Antimicrobial Agents and Chemotherapy, June 2000) conducted a study to assess the effectiveness of echinacea (extracted from a perennial herb) for prevention of common colds and found that echinacea had no significant effect on either the occurrence of infection or the severity of illness. Klaus Linde et al in "Echinacea for Preventing and Treating the Common Cold" (Cochrane Library, 2005) conducted a comprehensive review that assessed the available evidence from clinical trials investigating the effectiveness of echinacea extracts for prevention and the treatment of the common cold. The results were more favorable than the earlier study, suggesting that some echinacea preparations may be better than placebo, for both treatment and prevention of colds, and may be more effective for treatment when taken at the onset of symptoms. The review did, however, call for additional research to confirm these findings.
Does DHEA Slow or Reverse Aging?
Dehydroepiandrosterone (DHEA) is the most plentiful steroid hormone in the body. It is produced in the adrenal glands, brain, and skin; in the body it is converted into other hormones such as estrogen and testosterone (the primary female and male sex hormones, respectively) and other steroid hormones. DHEA levels may be measured using a blood test. The amount of DHEA in the body starts to decline gradually at about thirty years old; it is also reduced during periods of illness. Laboratory research (as opposed to research conducted on human subjects) reveals that low DHEA levels are linked to heart disease and certain cancers.
In view of these findings, some CAM practitioners favor supplementing DHEA for people who no longer have peak levels of the hormone. They claim that studies support the findings that DHEA replacement increases physical stamina, muscle mass, immune functions, and emotional well-being while simultaneously promoting weight loss and reducing bone loss from osteoporosis. Skeptics cite other studies showing that taking DHEA may cause excessive, unwanted hair growth; a reduction in high-density lipoprotein (HDL), the lipid that protects against heart disease; and resistance to insulin, the hormone involved in glucose metabolism. They caution that replacing any hormone that normally declines with advancing age is perilous, especially because some cancers, such as breast and prostate cancers, thrive in the presence of hormones.
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