Ask the Doctors: Turmeric supplements shown to have some benefit
A: The turmeric powder found in spice racks — and the component of it found in supplements — comes from the underground stem of a plant native to India and southeast Asia, which is cooked and then ground to create an orange-yellow powder. Long used in Ayurvedic medicine to control inflammation and pain and to treat upper respiratory infections, turmeric contains compounds with anti-inflammatory and antioxidant agents. The best-known and most-studied is curcumin.
One big problem with assessing the impact of curcumin is that, in its pure form, the compound is poorly absorbed by the body and is quickly eliminated. A 2016 study reviewed six studies that used turmeric or curcumin specifically for arthritis pain, comparing them to either a placebo, glucosamine or the NSAIDs ibuprofen or diclofenac. The dosage of curcumin in the studies varied from 100 milligrams to up to 2,000 milligrams per day.
The studies found that curcumin decreased pain significantly compared to placebo and that it was comparable to ibuprofen and diclofenac in decreasing pain and stiffness. Side effects of curcumin included sore throat, gastrointestinal bloating, swelling around the eyes and itching. These side effects were more frequent at doses higher than 1,200 milligrams. The authors noted that, while the benefits seen with curcumin were encouraging, the number of people involved was small and the studies had methodological flaws. Further, the longest study in this group lasted only four months, so long-term side effects or benefits couldn't be assessed.
That hasn't quelled enthusiasm for the compound, however, and the anti-inflammatory effects of it are touted even as a possible Alzheimer's preventive. Amyloid deposits are a telltale sign of the disease, and curcumin has been shown to exhibit anti-amyloid activity. Multiple studies in mice and rats genetically modified to have Alzheimer's have shown that the addition of curcumin to their diets reduced the deposits of amyloid within the brain and decreased the markers of brain inflammation. However, these animal studies used either intravenous or intraperitoneal curcumin, not oral, so I don't think that the pills you find in health food stores would be as potentially helpful.
As for cancer, research shows that curcumin can inhibit multiple cancers in a laboratory environment and in mice. This benefit was also seen in conjunction with traditional chemotherapeutic agents, suggesting curcumin might enhance the activity of chemotherapy and decrease some of its side effects. The studies are still in their infancy in humans, so it is difficult to make any definitive conclusions.
We truly need more studies of turmeric and, more specifically, curcumin before either can be recommended as a therapeutic agent. If you're determined to use one or the other for arthritic pain, I would recommend preparations of curcumin — and in doses of less than 1,200 milligrams to minimize side effects. In the future, the benefits of curcumin may improve if it's combined with an inert substance that allows the compound to be absorbed more easily and excreted less quickly.
Robert Ashley, M.D., is an internist and assistant professor of medicine at the University of California, Los Angeles.
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