In recent years, the popularity of complementary and alternative medicine (CAM) and vitamin therapy has increased dramatically. This led the National Institutes of Health (NIH) to create the National Center for Complementary and Alternative Medicine (NCCAM). It provides funding — a lot of funding — to study many of these treatments.
Fourteen years and more than $3 billion later, what have we learned? As you might predict, it's a bit of a mixed picture. Well-designed research studies found that some treatments were effective.
But most of the funded studies found no benefit for an array of popular treatments.
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Treatments That Work
Well-designed studies have found only a few CAM treatments to be beneficial:
- Ginger for nausea associated with chemotherapy
- Acupuncture for knee arthritis or low back pain (although studies of sham acupuncture for back pain found similar benefit to actual acupuncture)
- Yoga, massage and meditation for fatigue, pain and anxiety
- Tai Chi for fibromyalgia
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Treatments That Don't Work
The disappointing truth is that most of the NCCAM-funded trials have found no evidence of benefit (as compared with a placebo) for some of the most commonly accepted treatments. These include:
- Echinacea to treat colds
- Ginkgo biloba to improve memory
- Glucosamine and chondroitin to improve joint health
- Black cohosh for hot flashes
- Saw palmetto for prostate disease
- Shark cartilage to treat cancer
- Soy for improving bone density
Yet, people spend millions of dollars a year for these treatments.
Creating the NCCAM was, at first, controversial. Many scientists who are skeptical of CAM wondered why we should spend scarce research dollars to study these treatments. They had little or no "biologic plausibility" — the idea that the association makes biologic sense. And for many of the treatments studied, there had been little or no scientific evidence of benefit. After all, the NIH typically uses biologic plausibility and at least preliminary scientific evidence as starting points to make funding decisions. But supporters of studying CAM argued that the popularity of these treatments made it imperative that we study them.
The largely negative findings could affect the future of the NCCAM. Still, every negative study has limitations that could justify additional study. For example, there are more than 100 brands of black cohosh. A negative study using one does not necessarily prove that other brands are ineffective for hot flashes.
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Health Claims for Vitamins
Several recent studies have called into question the health claims of taking vitamins. For example:
- Multivitamin use did not reduce the risk of cancer or heart disease among postmenopausal women.
- Calcium and vitamin D did not reduce women's risk of breast cancer or bone fractures.
- Vitamin E, vitamin C and selenium did not lower men's risk of prostate cancer or other cancers.
However, not all vitamin studies have been negative. For example, trials of a combination of antioxidants (vitamin C, vitamin E, beta-carotene and zinc) concluded that they were somewhat helpful in preventing severe macular degeneration in older adults at high risk for this condition.
And, of course, individual circumstances may make one or more vitamins particularly helpful. Examples include:
- Pregnant women should take folic acid, as it dramatically reduces the risk of birth defects.
- People with osteoporosis and a diet low in calcium and vitamin D should take these supplements.
- Anyone whose nutrition is questionable should take a multivitamin as a bit of insurance that they're getting the vitamins they need.
For many people taking supplements, the results of these studies may not matter. In fact, people seem content to perform "N of 1" trials.
In research studies, the letter "N" refers to the number of research subjects enrolled. In an "N of 1" trial, there is only one person in the study. For example, researchers may treat a person with arthritis with a different pain reliever each week. They rate the effectiveness of each medicine to see if one medicine is clearly better or worse than another. In "real life" (as opposed to research trials), we do this all the time. We try a medication and if it seems to work, we tend to stick with it. If it doesn't work, we try something else.
Many people care little about research findings. They care only about their own experience with a particular treatment. That's understandable. A given treatment may not work well on average for a group of people. But it may help some individual people in the group feel better.
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Are the Studies Worth Funding?
Was the NCCAM's $3 billion well spent?
Skeptics of CAM would say no because:
- Most studies have been negative.
- The negative results could have been predicted based on lack of biologic plausibility and lack of preliminary data showing effectiveness.
- These billions of dollars would have been better spent on other, more pressing diseases, such as AIDS, cancer and heart disease.
- Funding studies of CAM should not be a priority for governmental agencies, such as the NIH. Let others fund these studies.
Supporters of CAM or the NCCAM might say that these studies were worthwhile and appropriate because:
- It's in the interest of public health to know whether CAM approaches are safe and effective.
- Some treatments that turn out to be effective had little biological plausibility when first used. One example that comes to mind is gold injections for rheumatoid arthritis.
- Governmental agencies are in the best position to evaluate and fund research proposals of CAM.
- As a major purchaser of health care (through Medicare, Medicaid and other government-based health care insurers), the government has an interest in knowing whether CAM approaches are safe and effective.
- If this research is left to other funding sources, the results may not be as readily accepted. For example, a study funded and performed by proponents or practitioners of CAM might be viewed as tainted or biased.
I think there are valid points on both sides of the issue. In my view, the NCCAM serves a useful purpose. But, clearly it should be highly selective about the studies it chooses to fund. Grants approved by NCCAM to study treatments without a biological foundation (such as prayer for weight loss) are unlikely to provide definitive findings.
Studies of vitamins are a bit easier for me to justify. Most vitamins are compounds known to serve some physiologic role in the body. As a result, it is biologically plausible that vitamins might help to treat or prevent illness. Identifying which vitamins and which doses are helpful for which diseases seems a worthy goal, regardless of the funding source.
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The Bottom Line
I have long agreed with Dr. Marcia Angell, former editor of the New England Journal of Medicine, who suggested we stop using the term "CAM." Instead we should classify treatments as proven or unproven.
It will never be easy to decide which research studies of unproven treatments should be funded and by whom. But that's always been true, regardless of whether we call it CAM, vitamin treatment or something else.
Robert H. Shmerling, M.D. is associate physician at Beth Israel Deaconess Medical Center and associate professor at Harvard Medical School. He has been a practicing rheumatologist for over 20 years at Beth Israel Deaconess Medical Center. He is an active teacher in the Internal Medicine Residency Program, serving as the Robinson Firm Chief. He is also a teacher in the Rheumatology Fellowship Program.