Mediterranean Diet Soothes Aching Joints

Foods rich in antioxidants help people with rheumatoid arthritis

WEDNESDAY, Feb. 19, 2003 (HealthDayNews) -- A Mediterranean diet high in olive oil, cooked vegetables, and fish appears to ease symptoms of rheumatoid arthritis.

A small Swedish study in the March issue of the Annals of the Rheumatic Diseases has found that people who followed this eating regimen had less inflammation and were more active at the end of three months.

Outside experts, however, say this study is far from the final word on the subject.

"The design is flawed and the results are, at best, modest," says Dr. Clifton Bingham, director of the Seligman Center for Advanced Therapeutics at the Hospital For Joint Diseases in New York City. "The results they find are statistically significant, but it's not clear that any of the results are clinically significant."

Rheumatoid arthritis is an autoimmune disorder that involves inflammation to the lining of the joints and possibly other organs.

Previous research has shown a link between fish oil -- which has anti-inflammatory properties -- and the treatment of rheumatoid arthritis, Bingham says. However, the amounts required are so high that they have little relevance to a person's daily diet.

This study looked specifically at the Cretan Mediterranean Diet, which includes copious amounts of fruit, vegetables, cereals, legumes, poultry, and fish. Red meat and high-fat dairy products are kept to a minimum and olive and canola oils are the primary source of fat.

Fifty-one people with stable though active rheumatoid arthritis were randomly assigned to either the Cretan diet or to a "typical" Western diet for three months.

For the first three weeks, participants ate lunch and dinner at the clinic's cafeteria. They were then provided with instructions and recipes and left to their own devices. Clinical examinations looking at physical function, quality of life, joint pain and other measures were performed at the beginning and then at the third, sixth and 12th weeks of the study.

Little progress was seen before the six-week mark. By the end of the 12-week period, physical function, vitality, and various other measures had improved in the Mediterranean-diet group but not in the control group. People in the treatment group also lost an average of three kilograms (6.6 pounds).

The diet had the advantage of being relatively easy to follow and the majority of participants liked it.

"A general idea of mine is that the Mediterranean diet is palatable and should be easy for most patients to accept, even lifelong," says Dr. Lars Skoldstam, lead author of the study.

The researchers speculate that olive oil can be metabolized into agents with anti-inflammatory effects and that olive oil also has antioxidant properties. Vegetables are also rich in natural antioxidants, which help control inflammation, Skoldstam says.

Because obesity is a risk factor for rheumatoid arthritis, Skoldstam believes the weight loss may also have had a salutary effect.

"A hypothesis of mine is that the weight reduction induced metabolic regulatory mechanisms which, in their turn, down-regulated the arthritis of the patients," he says. "A considerable proportion of our patients were overweight."

Unfortunately, flaws in the study design cast doubt on the relevance of the findings. In addition to being an extremely small sample, the study was not blinded either for the patients or for the people doing the assessments. "These are both fatal flaws in interpreting the data," Bingham says. "You don't know what they are receiving unless you actually controlled all of the food they were receiving yourself."

However, the diet may still make sense for rheumatoid arthritis sufferers, because this group of people has a higher cardiac risk than people without the condition.

"Treatments such as dietary modification that would lower other cardiac risk factors such as elevated cholesterol may certainly modify long-term cardiac outcome for patients with [rheumatoid arthritis]," Bingham says. "Patients lost weight in the treatment group, and that would be something that may benefit patients."

Bingham does not give patients with rheumatoid arthritis any specific dietary advice, just to eat a balanced diet that is low in fat and cholesterol and contains sufficient quantities of vitamins and minerals.

And one more bit of advice: "The effect sizes that are seen [in this study] are nowhere near the results obtained with currently available medications to treat rheumatoid arthritis," Bingham says. "Diet should never be seen as the sole therapy for this disease but, rather, at best adjunctive."

More information

For more on rheumatoid arthritis, visit the Arthritis Foundation or the National Institute of Arthritis and Musculoskeletal and Skin Conditions.

The American Heart Association has information on the Mediterranean diet.

SOURCES: Clifton Bingham, M.D., director, Seligman Center for Advanced Therapeutics, Hospital For Joint Diseases, New York City; Lars Skoldstam, M.D., Ph.D., department of medicine, Kalmar County Hospital, Kalmar, Sweden; March 2003 Annals of the Rheumatic Diseases
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