Long Term Immunomodulatory Effects of a Mediterranean Diet in Adults at High Risk of Cardiovascular Disease in the PREvencion con DIeta MEDiterranea (PREDIMED) Randomized Controlled Trial.
BACKGROUND The Mediterranean diet (MedDiet) has demonstrated short term anti inflammatory effects, but little is known about its long term immunomodulatory properties. OBJECTIVE Our goal was to assess the long term effects of the MedDiet on inflammatory markers related to atherogenesis in adults at high risk of cardiovascular disease (CVD) compared with the effects of a low fat diet (LFD) METHODS We randomly assigned 165 high risk participants (one half men; mean age: 66 y) without overt CVD to 1 of 3 diets: a MedDiet supplemented with extra virgin olive oil, a MedDiet supplemented with nuts, or an LFD. Follow up data were collected at 3 and 5 y. Repeated measures ANOVA, adjusted for potential confounding variables, was used to evaluate changes in diet adherence, CVD risk factors, and inflammatory variables. RESULTS The 2 MedDiet groups achieved a high degree of adherence to the intervention, and the LFD group had reduced energy intake from fat by 13% by 5 y. Compared with baseline, at 3 and 5 y, both MedDiet groups had significant reductions of =16% in plasma concentrations of high sensitivity C reactive protein, interleukin 6, tumor necrosis factor a, and monocyte chemoattractant protein 1 (P 0.04) whereas there were no significant changes in the LFD group. The reductions in CD49d and CD40 expressions in T lymphocytes and monocytes at 3 y were =16% greater in both MedDiet groups than were the changes in the LFD group (P 0.001) at 3 y. Compared with baseline, at 3 y, the MedDiet groups had increased HDL cholesterol =8% and decreased blood pressure >4% and total cholesterol, LDL cholesterol, and triglyceride =8% concentrations. At 5 y, concentrations of glucose (13% and glycated hemoglobin (8% had increased with the LFD. CONCLUSIONS The MedDiet participants had lower cellular and plasma concentrations of inflammatory markers related to atherosclerosis at 3 and 5 y. This anti inflammatory role of the MedDiet could explain in part the long term cardioprotective effect of the MedDiet against CVD. This trial was registered at controlled trials.com as ISRCTN35739639.
The Journal of nutrition