A Swedish study suggests that a Mediterranean type of diet - one that emphasizes fish, olive oil, whole grains, legumes, and fruits and vegetables, and limits red meat, animal fats, and processed foods - can help control the inflammation of rheumatoid arthritis. The findings have been published in the journal Annals of the Rheumatic Diseases.

A look at diet and arthritis

The researchers recruited 51 people with rheumatoid arthritis. Twenty-six of them were asked to follow a Mediterranean diet. They ate their meals in the health center cafeteria for 3 weeks, and then received instruction on how to prepare appropriate meals at home. The remaining participants followed their usual diets. Tests designed to measure joint tenderness, swelling, pain, and overall physical function were done periodically during the 12-week study.

There was no measurable difference between the two groups for the first half of the study. But after several months, those on the Mediterranean diet were showing markedly fewer swollen joints and less pain; they also reported improvements in physical function. In an added benefit, participants following the Mediterranean diet reduced their cholesterol levels. Those who followed their usual diets showed no such improvements.

How diet might help

It's not yet clear how diet may affect rheumatoid arthritis, but the authors point out that the disease is less common in countries where a Mediterranean style of eating is the norm. They say that this may be due to the foods featured in this type of diet. Fish is a prime source of omega-3 fatty acids, a "healthy" type of fat that scientists think may help reduce inflammation. Olive oil is rich in a type of fat that readily converts to a fatty acid similar to omega-3's. In addition, olive oil, fruits, and vegetables are prime sources of antioxidants, which can help limit cell damage and control inflammation.

Advice to consumers

This was a small study that included only those with fairly well-controlled rheumatoid arthritis, so more research is needed to get a better idea of exactly how certain foods might help control inflammation. But a Mediterranean style of eating has health benefits that reach beyond its effect on arthritis - scientists also think that this type of diet may help reduce the risk of heart disease and some forms of cancer.

For more information on how specific kinds of food fit into a Mediterranean style of eating, check the Mediterranean Food Pyramid featured on MayoClinic.com (see first link below).