Effect of an Indo-Mediterranean diet on progression of coronary artery disease in high risk patients (Indo-Mediterranean Diet Heart Study): a randomised single-blind trial (Publication with Expression of Concern)

Background The rapid emergence of coronary artery disease (CAD) in south Asian people is not explained by conventional risk factors. In view of card ioprotective effects of a Mediterranean style diet rich in alpha-linolenic acid, we assessed the benefits of this diet for patients at high risk of CAD. Methods We did a randomised, single-blind trial in 1000 patients with angina pectoris, myocardial infarction, or surrogate risk factors for CAD. 499 patients were allocated to a diet rich in whole grains, fruits, vegetables, walnuts, and almonds. 501 controls consumed a local diet similar to the step I National Cholesterol Education Program (NCEP) prudent diet. Findings The intervention group consumed more fruits, vegetables, legumes, walnuts, and almonds than did controls (573 g [SD 127] vs 231 g [19] per day p<0.001). The intervention group had an increased intake of whole grains and mustard or soy bean oil. The mean intake of alpha-linolenic acid was two-fold greater in the intervention group (1.8 g [SD 0.4] vs 0.8 g [0.2] per day, p<0.001). Total cardiac end points were significantly fewer in the intervention group than the controls (39 vs 76 events, p<0.001). Sudden cardiac deaths were also reduced (6 vs 16, p=0.015), as were non-fatal myocardial infarctions (21 vs 43, p<0.001). We noted a significant reduction in serum cholesterol concentration and other risk factors in both groups; but especially in the intervention diet group. In the treatment group, patients with pre-existing CAD had significantly greater benefits compared with such patients in the control group. Interpretation An Indo-Mediterranean diet that is rich in alpha-linolenic acid might be more effective in primary and secondary prevention of CAD than the conventional step I NCEP prudent diet.