Could the Mediterranean Diet Improve Arthritis?

Answer: Switching to a Mediterranean diet could reduce levels of pain and their morning stiffness in patients with rheumatoid arthritis.

We've seen that following a Mediterranean-style diet can help with dementia, stomach and breast cancers, heart disease, and even mood. Cancers and heart disease are understood to be in part due to inflammation, as is rheumatoid arthritis.

The Research

Researchers in Sweden recruited 51 adult men and women who had been living with a diagnosis of rheumatoid arthritis for at least 2 years, with their condition being considered "active" and "stable" by their physician.1 To participate, their antirheumatic medications had to have been unchanged for a minimum of 3 months, their steroid dosage stable for at least 4 weeks, and their intake of NSAIDs (a class of drugs that include acetaminophen, ibuprofen, and naproxen) stable for at least 10 days.

Half the participants were assigned to a Mediterranean-style diet, while the other half continued their customary diet. For the first 3 weeks of the 3-month study, those assigned to a Mediterranean-style diet received their lunch and dinner meals in the lab. During those 3 weeks the participants had 6 classes with a dietitian to learn about Mediterranean food and cooking, then received instructions and recipes to continue their assigned diet at home. The researchers provided the Mediterranean diet participants with olive oil, canola oil, frozen vegetables, and tea (to substitute for the polyphenols in wine) to make it easier for the participants to stick with the diet.

At the start of the study and at 3 weeks, 6 weeks, and 12 weeks (the end of the study), all of the participants, both usual diet and Mediterranean-style diet, responded to standardized questionnaires that measure the overall effects of rheumatoid arthritis, including the number of swollen or tender joints and the length of time it takes for morning stiffness to go away, along with overall pain scores. They also kept daily records of how much NSAIDs they used each day and visited physiotherapists who measured their physical function, including a grip test. Further, their blood was tested to measure erythrocyte sedimentation rate (ESR), which is used to assess general inflammation levels in the body.

The Results

After the 12 weeks of the study, those who had followed a Mediterranean-style diet reported significantly lower levels of pain and their morning stiffness went away more quickly. Those who continued with their usual diet, however, saw their pain levels increase slightly along with the duration of their morning stiffness. Interestingly, neither their NSAID use nor their ESR changed significantly.

What’s The “Take Home”?

This is a fairly short study, but that short length might be considered encouraging: a change in diet might yield results in just a few months. That said, those who were assigned to the Mediterranean-style diet tended to have a higher body mass index than those who continued on their usual diet, and some lost weight during the study. They had also contended with their arthritis diagnosis for longer. It's possible that weight loss made a difference, and that those who'd had arthritis for longer might respond to a change to a healthier diet regardless of the specific type of diet.

On the other hand, if following a Mediterranean-style diet means greater quality of life when living with rheumatoid arthritis, wouldn't you want to have those effects for as long as possible?

Reference:

1. Skoldstam L, Hagfors L, Johansson G. An experimental study of a Mediterranean diet intervention for patients with rheumatoid arthritis. Ann Rheum Dis. 2003;62:208-214.