Ask Tufts Experts

My son-in-law is troubled with arthritis in his hands. My daughter read “somewhere” that eating cherries might alleviate the problem. Is there any evidence that eating cherries or drinking cherry juice will help against arthritis?

Sour cherries in particular have long been used in folk medicine as a remedy for inflammation. Today, scientists are exploring the possible benefits of antioxidants in cherries and other fruits. Cherries contain antioxidants, including kaempferol and quercetin, which may have anti-inflammatory effects. Most red-colored fruits also contain cyanidin, an antioxidant that helps give them their color. A 2005 Chinese study of the effects of cyanidin from cherries on inflammation in rats concluded that it “could be one of the potential candidates for the alleviation of arthritis.”

But the findings to date are a long way from a prescription for guzzling cherry juice or gobbling cherries to fight arthritis. In fact, last year the US Food and Drug Administration (FDA) sent warning letters to 29 cherry marketers to stop making “unproven claims” for the fruit’s medicinal qualities—including cancer, heart disease, gout, diabetes and arthritis. (See the January 2006 Healthletter.)

The Arthritis Foundation “does not see any harm in eating cherries for antioxidant protection, but does not believe there is enough proven clinical evidence to suggest that eating cherries is beneficial for reducing the pain and inflammation associated with arthritis.”

I recently read an article on “Modified Citrus Pectin” (MCP) and its possible effectiveness in fighting cancer. What can you tell me about MCP?

Pectin is a carbohydrate found in fruit, especially in the peel and pulp of ripe citrus fruits; modified citrus pectin (MCP), also known as fractionated pectin, has been altered to be more easily digested. According to a 2000 monograph in Alternative Medicine Review, MCP “is rich in galactoside residues, giving it an affinity for certain types of cancer cells. Metastasis is one of the most life-threatening aspects of cancer and the lack of effective anti-metastatic therapies has prompted research on MCP’s effectiveness in blocking metastasis of certain types of cancers, including melanomas, prostate and breast cancers.” In 2003, a very small—13 men—study of MCP’s effect on prostate cancer did suggest “that MCP may lengthen the prostate-specific-antigen (PSA) doubling time in men with recurrent prostate cancer,” in effect potentially slowing the cancer’s progression. According to the University of Texas M.D. Anderson Cancer Center, in another study, MCP inhibited metastasis in rats injected with melanoma and human prostate cancer cells. Such animal studies have explored the mechanisms by which MCP works, “but these results have not been translated to humans yet.”

The FDA classifies citrus pectin as “Generally Regarded As Safe” (GRAS), and side effects of MCP treatment are rare. It’s too early to say, however, whether MCP will ultimately live up to its promise as a weapon against metastasis in humans.