Chefs will be happy to note: A Mediterranean diet supplemented with extra virgin olive oil reduced inflammation markers and risk for atrial fibrillation (AF) in a cohort followed by the PREDIMED Trial.

This study was published in the July 1 issue of Circulation.

Spanish researchers followed three subgroups over a median of nearly five years: Mediterranean diet supplemented with extra virgin olive oil, Mediterranean diet supplemented with nuts, and a control diet involving low-fat recommendations. While a Mediterranean diet supplemented with nuts showed a small reduction of cardiovascular risks, extra virgin olive oil was far more effective in reducing risks for stroke, cardiovascular death and MI with a 38 percent reduction in risk for AF.

Miguel Á. Martínez-González, MD, PhD, of the University of Navarra in Pamplona, and colleagues noted that previous studies recorded a relationship between C-reactive protein, interleukin 6 and other inflammatory biomarkers in the development of AF. The initial review of the PREDIMED (Prevencíon con Dieta Mediterránea) Trial data showed a significant reduction in the C-reactive protein of those subjects in the extra virgin olive oil group. This, they believe, led to an AF rate of 6.8 per 1,000 person years in that group.

Martínez-González et al suggested that this might relate to the quantity of intake as well. At the end of the trial, extra virgin olive oil consisted of 22 percent of caloric intake in that cohort, whereas whatever effect nuts may have had was tempered by the fact that they were consumed at a far lower 8 percent of total intake.

In total, 72 new cases of AF occurred in the extra virgin olive oil group out of 2,292 participants, 92 new cases in the nuts cohort (2,210 participants), and 89 in the control diet (2,203 participants).  The hazard ratio for extra virgin olive oil and nuts against the control diet cohort was 0.62 and 0.89 respectively.

This study represented a second pass at the PREDIMED Trial results. The earlier work reviewed other cardiovascular markers, looking to see if a Mediterranean diet supplemented with either extra virgin olive oil or nuts was better than a low-fat diet in controlling and protecting against risks of stroke, MI or cardiovascular death.