What they are: These natural products contain more than one herb or natural compound, explained Richard Nahin, one of the co-authors of the NCCAM surveys and the acting director of its division of extramural research. Two examples are a glucosamine/chondroitin blend for osteoarthritis or a combination of echinacea and goldenseal as an herbal remedy to help relieve a cold.
What they're supposed to do: Combination products are sold for a host of conditions, from the common cold and pain relief to anxiety and heart health, to name a few.
What research suggests: These days, most of the research on dietary supplements tends to focus on single ingredient herbs or supplements, to make it easier for scientists to pinpoint whether a natural product is having an influence on the condition or symptom being studied. "The question that comes up when combining things, is what's working?" pointed out Dr. Mimi Guarneri, medical director for the Scripps Center for Integrative Medicine in La Jolla, Calif. For example, it's harder to tease out which ingredient in a pain-relieving remedy is helping to ease inflammation and swelling when it contains many different herbs that might play a beneficial role.
Bottom line: According to Guarneri, she wouldn't necessarily shy away from suggesting that a patient use a combination product because sometimes she has found that they work better than one supplement alone, because the ingredients can have an additive effect. "Some combination products are really good. As a clinician, I would look at what the individual components are in a product and whether I know them to cause any benefit."
What it is: The claim to fame for this extract made from the leaves of an ancient tree is its antioxidant activity, as well as its potential to improve blood flow to the brain.
What it's supposed to do: Ginkgo is best known for its possible brain-boosting powers. The herb has been studied for its ability to prevent and treat dementia, and has also been looked at for improving cognitive function, such as memory, in healthy adults.
In Germany, the remedy has been used to treat vascular claudication, a type of pain that occurs while walking because the leg doesn't get enough blood. The Mayo Clinic is currently analyzing data from a more than three-year trial on the use of ginkgo in cancer patients experiencing "chemobrain," a type of mental fogginess that occurs in some people following chemotherapy and radiation.
What research suggests: Although studies done 10 or 15 years ago on gingko seemed initially promising, research done in the last year or two suggests that the herb may not work as a preventive for dementia, said Bauer. "The needle is pushing more in the direction that we're not seeing a strong protective effect on dementia."
He cautioned that the jury is still out because ginkgo can cross the blood-brain barrier and has antioxidant properties, meaning it can squelch free radicals.
Bottom line: Ginkgo is a vasodilator, so it might do something to increase blood flow, noted Bauer. He said small studies suggest some ability to improve cognitive function in healthy people, but not enough to say you'll think better.
What it is: A chemical compound derived from cartilage, typically from the windpipe of a cow.