Dietary non enzymatic antioxidant capacity and the risk of myocardial infarction in the Swedish women's lifestyle and health cohort

Foods rich in antioxidants have been associated with a reduced risk of myocardial infarction. However, findings from randomized clinical trials on the role of antioxidant supplementation remain controversial. It has been suggested that antioxidants interact with each other to promote cardiovascular health. We therefore investigated the association between dietary Non Enzymatic Antioxidant Capacity (NEAC), measuring the total antioxidant potential of the whole diet, and the risk of myocardial infarction. We followed 45,882 women aged 30-49 years and free from cardiovascular diseases through record linkages from 1991 until 2012. Dietary NEAC was assessed by a validated food frequency questionnaire collected at baseline. Total dietary NEAC was categorized into quintiles and multivariable Cox proportional hazard regression models were fitted to estimate hazard ratios (HR) with 95% confidence intervals (CI). During a mean follow-up time of 20.3 years we detected 657 incident cases of myocardial infarction. After adjusting for potential confounders, we found a significant 28% lower risk of myocardial infarction among women in the fourth (HR: 0.72; 95% CI 0.55-0.95) and a 40% lower risk among women in the fifth quintile (HR: 0.60, 95% CI 0.45-0.81) of dietary NEAC compared to women in the first quintile, with a significant trend (p-value < 0.001). Higher dietary NEAC is associated with a lower risk of myocardial infarction in young to middle-aged women. These findings support the hypothesis that dietary antioxidants protect from myocardial infarction and that this effect might be exerted through interactions between antioxidants.