Lifestyle Interventions Based on the Mediterranean Diet for Patients With Rheumatoid Arthritis: a Randomized Controlled Trial

The effect of various dietary regimens and nutrient supplementation on rheumatoid arthritis (RA) has been previously explored, with the majority of the evidence supporting the beneficial effect of n-3 polyunsaturated fatty acids (PUFAs), consumed mainly as fish oil supplements. However, many capsules should be taken on a daily basis (10 - 15) in order to improve health status, increasing, thus, the high drug burden these patients may encounter; inability to comply with supplementation, as depicted in drop-out rates and adverse reactions, is also of concern. On the other hand, the so far investigation of specific dietary patterns, namely elemental or vegetarian diets, revealed similar limitations regarding inability to comply, without producing clear benefit.

The last decade, a traditional dietary pattern, the Mediterranean diet, has also been investigated in patients with RA. This pattern is characterized by abundance of plant foods (fruits, mainly as typical daily desserts, vegetables, bread, other forms of cereals, beans, nuts, and seeds), olive oil as the principal source of fat, moderate amounts of dairy products (mainly cheese and yogurt), low to moderate amounts of fish and poultry, red meat in low amounts and wine consumed in moderation, normally with meals. Adherence to the Mediterranean diet has been associated with a significant reduction in total mortality and improvement in longevity, as well as with lower incidence of atherosclerosis, coronary heart disease, metabolic syndrome and biochemical markers related to insulin resistance and inflammation. In RA, in specific, it has been shown to improve objective and subjective measures. It is also worth mentioning that this type of intervention produced negligible or no adverse effects or drop-out in RA patients. However, it has been implemented in North-European populations with a background diet far away from the Mediterranean dietary habits. It would be interesting to study the effect of a Mediterranean diet-based intervention in a Mediterranean population of RA patients, evaluate their adherence and changes in subjective disease measures as well as in biochemical markers. One of the markers of interest is adiponectin, a large 30-kDa protein produced mainly by adipocytes, sharing strong homologies with TNF and the complement factor C1q. Plasma levels of adiponectin have been negatively associated with indices of obesity, insulin resistance and cardiovascular disease. However, its role in RA is still controversial with some evidence indicating a proinflammatory effect and some other suggesting antiinflammatory properties of this adipocytokine.

Aim of the present study was to evaluate the effect of different lifestyle intervention administrations, in increasing adherence to the Mediterranean diet in a group of patients with RA living in the Mediterranean basin, and, thus, in improving parameters related to subjective and objective disease markers, including plasma adiponectin concentrations.