Out of frustration with conventional medicine or in hopes of preventing or treating disease, health consumers continue to turn to complementary and alternative medicine (CAM) treatments such as acupuncture, chiropractic care, herbs and supplements.
But of the many treatments in the rapidly growing, frequently bewildering field, what really works? With little gold-standard evidence to go by, that's been a hard question to answer. Long-standing attempts to perform high-quality research continue.
There is a "real effort to use state-of-the-art methodology -- using randomized, controlled trials [to determine] whether a [nonconventional] treatment is efficacious or not," said Michael Irwin, a professor at the UCLA Neuropsychiatric Institute specializing in mind-body medicine, including meditation and yoga.
Some of the biggest and best-designed trials are funded by the federal government, through the National Center for Complementary and Alternative Medicine (NCCAM), a unit of the National Institutes of Health (NIH). One NCCAM-funded trial, for example, is investigating whether massaging premature infants three times a day for 10 days speeds weight gain. Another trial, expected to produce results late this year, is studying the effectiveness of the dietary supplements glucosamine and chondroitin in treating osteoarthritis pain.
Many consumers aren't waiting for the verdicts. CAM therapies such as acupuncture, herbal medicine, osteopathy, massage and chiropractic care generated $36.5 billion in revenue last year, according to Nutrition Business Journal, an industry publication, up 67.4 percent from 1997, the first year it tallied such data.
In a survey of 34,000 readers of Consumer Reports, published in its August 2005 issue, nearly half reported using complementary or alternative treatments during the last two years. Respondents reported mostly good results with hands-on treatments, such as massage and chiropractic care for treatment of back pain and arthritis. But such self-reports don't constitute convincing evidence that a therapy is safe or effective, say experts.
Below is a quick survey of some CAM treatments that have been the subject of the most rigorous independent studies. Research does not support the therapies in all cases. The list is not exhaustive -- far too many treatments exist for that to be feasible. Some widely used therapies that have undergone little scientific scrutiny, such as homeopathy and intercessory prayer, are discussed elsewhere in this issue. (See "Probing Edges of Medicine -- and Reality," Page F1.) Small, less conclusive studies suggest benefits for some therapies.
For further information on research into specific treatments, see the Web sites for NCCAM (http://nccam.nih.gov) or the Mayo Clinic's Complementary & Alternative Medicine Center (www.mayoclinic.com; search for "alternative medicine"). For details about herbs and supplements, consult NIH's Office of Dietary Supplements (ODS), http://ods.od.nih.gov.
A facet of traditional Chinese medicine, acupuncture is one of the most thoroughly researched CAM therapies. Developed more than 2,000 years ago, this treatment involves inserting thin needles into the skin at specific points on the body, and manipulating them by hand or electrical stimulation.
A meta-analysis of 33 randomized, controlled trials, published in last month's Annals of Internal Medicine, found acupuncture more effective than sham treatment for short-term relief of chronic low-back pain. Not enough data existed to compare acupuncture to other therapies. Little is known about the mechanism by which acupuncture relieves pain.
Another study, published in 2004 in the Annals of Internal Medicine, found that acupuncture appeared to help relieve pain and improve function for patients with knee osteoarthritis.
NCCAM counted 537 clinical trials involving such manipulative and body-based therapies as chiropractic manipulation and massage between 1994 and 2004; 422 were randomized, controlled trials.
* Chiropractic Studies of chiropractic treatments, which involve manipulation of the spine, joints and muscles, for low-back pain have been of "uneven quality and insufficient to allow firm conclusions," reports NCCAM.
A 2003 Annals of Internal Medicine meta-analysis of 39 randomized clinical trials found chiropractic care more effective than sham treatments for acute and chronic low-back pain. No difference in effectiveness was found compared to such treatment categories as doctor's care, physical therapy and exercises.
NCCAM says more research is needed to determine the value of chiropractic care for other medical conditions, such as arthritis. More research is also necessary to understand what happens in the body during and after chiropractic treatments.
* Massage Therapy Studies suggest that this approach, involving joint manipulation complemented by physical therapy and the teaching of proper posture, can produce physiological changes tied to feeling better. It's been shown to alter various chemical, hormonal and immune markers, such as levels of substance P (a protein that increases pain messages) in those with chronic pain, according to NCCAM.
But a single research group did most of the studies. Further research by other groups is needed, says NCCAM, along with a better understanding of the mechanism by which massage works.
This category encompasses therapies that call on "emotional, mental, social, spiritual and behavioral factors" to impact health, according to NCCAM. Such popular techniques as meditation, cognitive behavioral therapy, biofeedback and guided imagery fall under this rubric.
Considerable evidence suggests mind-body therapies can improve postsurgical outcomes and reduce mortality rates from coronary artery disease by using various techniques to reduce anger, hostility and stress. Mind-body therapies have also been shown effective in treating incontinence, chronic low-back pain, headaches, insomnia, and nausea, vomiting, pain and functioning problems caused by chemotherapy, according to an extensive 2003 review published in the Journal of the American Board of Family Practice.
A shortcoming of the studies analyzed was the absence of sham treatment groups, because practitioners and patients often could not be blinded to the type of treatment being given.
* Meditation This technique has been found to activate parts of the brain used for attention and control of the nervous system. In a 2003 study in the journal Psychosomatic Medicine, researchers used magnetic resonance imagery (MRI) to show that meditation increased left-brain activity, which is associated with positive emotional states.
* Cognitive Behavioral Therapy Evidence suggests that this technique, a form of psychotherapy used to help patients change dysfunctional patterns of thinking, may be useful as a complementary treatment for coronary artery disease and some chronic pain conditions because it can help patients learn to deal with stress. Studies show this technique may be useful for treating many chronic conditions, when it is combined with an educational or informational component, NCCAM says.
* Biofeedback Evidence supports the effectiveness of this relatively well-researched technique. Using sensors that track bodily changes, patients learn to relieve stress and chronic pain by controlling functions such as heart rate, muscle tension, breathing, skin temperature and blood pressure through relaxation, imagery and other techniques. Biofeedback has been proven helpful in treating about 150 medical conditions, including migraines, arthritis and fibromyalgia, according to the Mayo Clinic.
More evidence supports the efficacy of dietary supplements comprised of single ingredients (vitamins and minerals, for example) than for botanical extracts, whose chemical composition may differ from product to product.
Much of the research on dietary supplements is marred by poor design and small sample size, researchers report. Recent studies have shown that dietary supplements can interact with drugs, and some herbal supplements can be toxic. The ODS warns consumers to beware of products said to cure and treat disease or to be "all natural," "totally safe," with "no side effects."
* Chondroitin Sulfate and Glucosamine Natural and synthetic versions of chemicals produced in the body and known to be involved in cartilage repair and maintenance, these two supplements are often sold in combination as a treatment for osteoarthritis. More evidence supports benefit from glucosamine than chondroitin sulfate, according to the University of California's Berkeley Wellness Letter, which evaluates research on herbs and supplements. Glucosamine supplements have been shown to slow the deterioration of cartilage and relieve pain in some patients with knee osteoarthritis. But the body's ability to absorb chondroitin sulfate from a supplement and use it for joint protection is still unclear. A large NIH trial underway may provide more answers.
* Echinacea Studies have produced conflicting findings on this herb's purported ability to boost the immune system and shorten the duration or ease the severity of colds, according to the Berkeley Wellness Letter. One problem: Echinacea supplements contain a mix of chemicals; it's not clear which, if any, might stimulate the immune system or encourage healing. Because little is known about the product's toxicity, the letter advises, echinacea should not be taken by people who are HIV-positive, pregnant or have lupus, rheumatoid arthritis, tuberculosis or multiple sclerosis.
* Saw Palmetto No gold-standard clinical trials support claims that this plant supplement shrinks enlarged prostates or provides other benefits, reports the Berkeley publication. So far, the studies showing effectiveness have been small. Saw palmetto supplementation can alter the results of PSA tests, making prostate cancer harder to diagnose, says the Berkeley letter. If you're taking it, let your doctor know.
* St. John's Wort Some evidence suggests that this extensively studied supplement may help relieve milder forms of depression, but the research is not conclusive. Berkeley advises that patients "think twice before taking it" and consult first with their doctor or therapist, particularly if they're also taking any prescription medications. For example, it is believed to interact with birth control pills and selective serotonin reuptake inhibitor (SSRI) drugs, used to treat depression, according to the ODS.