another article came out of the PREDIMED study (prevention with mediterranean diet study), where 6705 people without prevalent afib were randomly assigned to one of 3 diets: mediterranean diet supplemented with extra-virgin olive oil, mediterranean diet plus mixed nuts, or control group (low fat diet). in this post-hoc analysis they looked at the development of atrial fibrillation (see DOI: 10.1161/CIRCULATIONAHA.113.006921). [i posted blogs on 1/21/14 on primary CAD prevention and on diabetes prevention from this study — i appended excerpts below since they give details of diet]. the findings in the current study were:
–new cases of afib, after 4.7 years:
–med diet with supplemented extra-virgin olive oil: 72 cases, afib rate of 6.8 per 1000 person-years (and, there was a dose-response curve with higher olive oil consumption=less afib)
–med diet with supplemented mixed nuts: 82 cases, afib rate of 9.9 per 1000 person-years
–control diet: 92 new cases, afib rate of 10.1 per 1000 person-years
–so, HR of atrial fibrillation with extra-virgin olive oil vs control group was 0.62 (CI 0.45-0.85). non-significant diff between mixed nuts and control group (HR 0.89 with CI 0.65-1.20)
unclear why atrial fibrillation is decreased with olive oil. but, extra-virgin olive oil is known to have anti-inflammatory effects and reduces oxidative stress in patients with metabolic syndrome. there is argument in the literature that these factors are important in the development of afib (higher CRP or IL-6 levels assoc with development of afib. same with markers of oxidative stress).
limitations of study above include that afib was not the primary endpoint of the study (CAD, stroke were), and spanish study with mostly older white people at high cardiovascular risk, limiting potential generalizability. overall, i think that extra-virgin olive oil has pretty profound protective vascular effects, but i would caution about extrapolating this result in a reductionist way. the olive oil was consumed in the context of an overall healthy diet (Mediterranean diet) and seemed to add benefit. assuming that frying chicken with breadcrumbs in extra-virgin olive oil and then sprinkling the potato chips with a little more may not have the same positive benefit…..
geoff