Study Shows Mediterranean Diet Helps Patients with Rheumatoid Arthritis

Based on the abstract for “An experimental study of a Mediterranean diet intervention for patients with rheumatoid arthritis” by L. Skoldstam, L. Hagfors and G. Johansson

Edited (with Introduction) by Dr. Don Rose

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Much has been written about the benefits of a Mediterranean diet, which features greater consumption of fish, olive oil, and cooked vegetables. This study discusses such benefits as they relate to rheumatoid arthritis, a painful disease of the joints that many seniors suffer from. –D.R.

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OBJECTIVE

The objective of this study was to investigate the effectiveness of a Mediterranean diet (MD) -- with its greater consumption of fish, olive oil, and cooked vegetables -- as compared to an “ordinary” Western diet for suppression of disease activity in patients with rheumatoid arthritis (RA).

METHODS

Patients with well controlled although active RA of at least two years' duration, who were receiving stable pharmacological treatment, were invited to participate. All patients were randomly allocated to the MD or the control diet (CD). To achieve good compliance with prescribed diets, all patients were (for the first three weeks) served the MD or the CD, respectively, for lunch and dinner at the outpatient clinic's canteen.

Clinical examinations were performed at baseline (the beginning of the study), and again in the 3rd, 6th, and 12th week. A composite disease activity index (DAS28), a physical function index (Health Assessment Questionnaire (HAQ)), a health survey of quality of life (Short Form-36 (SF-36)), and the daily consumption of non-steroidal anti-inflammatory drugs were used as primary variables to judge the MD’s effectiveness.

RESULTS

From baseline to the end of the study, the patients in the MD group (n=26) showed a decrease in DAS28 of 0.56 (p<0.001), in HAQ of 0.15 (p=0.020), and in two dimensions of the SF-36 Health Survey: an increase in "vitality" of 11.3 (p=0.018) and a decrease in "compared with one year earlier" of 0.6 (p=0.016). For the control patients (n=25), no significant change was seen at the end of the study. This difference between the two treatment groups was notable only in the second half of the trial.

CONCLUSION

The results indicate that patients with RA, by adjusting to a Mediterranean diet (MD), did obtain a reduction in inflammatory activity, an increase in physical function, and improved vitality.

DISCUSSION AND LESSONS LEARNED

According to the full paper that describes this research, “[case]-control studies indicate that lifelong consumption of fish, olive oil, and cooked vegetables may have independent protective effects on the development or severity of rheumatoid arthritis (RA).”

Other studies, from selected geographical regions, support these hypotheses. In the Faroe Islands, where the typical diet is high in fish and whale meat, RA reportedly was mild. In northwestern Greece, where people consume high amounts of olive oil, the number of RA occurrences has reportedly been relatively low.

Other lessons learned regarding diet and RA:

· Supplementation of an “ordinary” Western diet with fish oils has been shown to “induce a weak anti-inflammatory effect”. In RA sufferers, “this effect was not detectable until after six weeks.”

· “Besides investigating the effects of specific nutrients and food items, attention should also be drawn to the diet as a whole. Ever since the Seven Countries Study, the MD -- particularly the Cretan MD -- has been regarded as a healthy and disease-preventing diet. The traditional Cretan MD is characterized by a high consumption of fruit, vegetables, cereals, and legumes. Compared with common Western diets, the MD contains less red meat and more fish. The Cretan MD typically uses olive oil as the primary source of fat, and also includes a moderate intake of wine.”

· “The fish consumed in Greece contain fewer n-3 fatty acids than deep ocean fish. This may explain why Linos and coworkers in their Greek case-control study found no significant evidence that fish consumption was an independent predictor of risk for RA. Instead, the two independent predictive factors turned out to be consumption of olive oil and cooked vegetables.”

· “Olive oil is rich in oleic acid (18:1n-9), which can be metabolized to eicosatrienoic acid (20:3n-9) -- with anti-inflammatory effects similar to those of n-3 PUFA from fish oils. Olive oil also has antioxidative properties. Greeks mainly consume the unrefined and unbleached virgin oil, which is rich in natural antioxidants including tocopherols.”

· “The other independent predictor of risk was consumption of cooked vegetables. Vegetables are particularly rich in a variety of natural antioxidants, which contribute to better control of inflammation. Antioxidants limit pathological aspects of the cytokine mediated response to inflammation. They also inhibit direct damage to tissues from all kinds of oxidative molecules that are released.”

· Other beneficial results noticed during this study: a fall in body weight and in serum cholesterol within the MD group.

While the results of this study are promising, the authors state that a “complete therapeutic evaluation will require larger numbers of patients to be followed up for a longer time, another budget, and collaboration with other [centers].”

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Dr. Don Rose writes books, papers and articles on computers, the Internet, AI, science and technology, and issues related to seniors.

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