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Popular Supplements Studied

Posted by medconsumers on March 1, 2006

Melatonin for sleep problems, glucosamine plus chondroitin for knee arthritis, and saw palmetto for symptoms of an enlarged prostate. Each one of these remedies has recently been subjected to a clinical trial that compared it against a placebo, or inactive pill. Results were disappointing.

All these remedies were classified as nutritional or dietary supplements that can be purchased over the counter, which is a large part of their appeal. So is the fact that these supplements are widely viewed as safer, more effective alternatives to prescription drugs. In all three cases, the supplements were compared with a placebo and found to be ineffective.

Manufacturers of dietary supplements are responsible for the safety of their products, but they not required by the FDA to prove that their products are effective. This minimal, or in some cases, complete lack of information makes the following studies all the more important to people who have been purchasing them for years.

Saw Palmetto for Prostate Symptoms

Saw palmetto is an herbal extract used by more than 2 million men in the U.S. to treat the symptoms of benign prostatic hyperplasia (BPH), or enlarged prostate.  The newly published clinical trial randomly assigned 225 men who had moderate to severe symptoms of BPH to take either 160 milligrams of saw palmetto twice a day, or a placebo. Neither the study participants nor the doctors who cared for them knew who was taking saw palmetto and who was taking a placebo.

After one year of treatment, the research team led by Stephen Bent, MD, and colleagues at several California medical institutions found the men taking saw palmetto showed no more improvement in urinary symptoms or quality of life than those who had been taking a placebo. This study was published in the February 9 issue of The New England Journal of Medicine. It was funded by grants from the U.S. National Institute of Diabetes and Digestive and Kidney Disease and the National Center for Complementary and Alternative Medicine.

Melatonin for Sleep Disorders

Melatonin is a hormone that is secreted by the pineal gland, a tiny cone-shaped organ in the brain that regulate the body’s sleep/wake cycles. Melatonin supplements have long been sold to the public as a way to hasten sleep or reduce the symptoms of jet lag.

Last month, the British medical journal, BMJ, published a review of all trials in which melatonin supplements were compared with placebo in people with sleep problems. Altogether there were 15 trials in which 524 people had been randomly assigned to take either melatonin or a placebo for three months or less. The supplement did not improve the study participants’ ability to fall asleep or reduce the sleep deprivation associated with jet lag. Nor did melatonin help people whose sleep problems were the result of working the night shift. The researchers determined that melatonin is safe for short-term use, but there is little information beyond that.

This review was funded by grants from the U.S. Agency for Research and Healthcare Quality and the Center for Complementary and Alternative Medicine.

Glucosamine and Chondroitin Sulfate for Knee Osteoarthritis

Glucosamine and chondroitin are substances found naturally in joints. Glucosamine is believed to repair the cartilage and chondroitin provides elasticity to the cartilage. Glucosamine and chondroitin sulfate are the two most widely used supplements in the U.S.

The newly published trial included 1,583 people with moderate to severe osteoarthritis of the knee who were randomly assigned to take 1500 milligrams of glucosamine,  or 1200 milligrams of chondroitin sulfate, or  both glucosamine and chondroitin, or 200 milligrams of celecoxib, sold as Celebrex, or a placebo each day for 24 weeks.

The research team led by Daniel O. Clegg, MD, University of Utah School of Medicine, Salt Lake, found that glucosamine and chondroitin sulfate alone or in combination did not reduce knee pain. There was some improvement in symptoms reported by the people taking Celebrex. While the majority of those on glucosamine plus chondroitin did not benefit, a minority on this combination did experience significant pain relief.

The researchers also noted a high rate of response among the people who had been taking the placebo. 61% of them reported reductions in pain; whereas drug trials typically show about 30% of the people taking a placebo report improvements.

This study, published last month in The New England Journal of Medicine, was funded by the National Center for Complementary and Alternative Medicine and the National Institute of Arthritis and Musculoskeletal and Skin Diseases.

Maryann Napoli, Center for Medical Consumers ©
March 2006

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