Overall dietary variety and adherence to the Mediterranean diet show additive protective effects against coronary heart disease

Abstract

Background and aim: Along with the increasing evidence of the cardioprotective effects of the Mediterranean Diet (MD), the scientific interest and advocacy of dietary variety as a potentially healthy eating habit gradually faded, until its complete oblivion in the latest European cardiovascular prevention guidelines. Our study aims to investigate whether dietary variety adds to the "Mediterranean-ness" of the diet in protecting against coronary heart disease (CHD).

Methods and results: In this case-control Italian study, data on eating habits were collected from 178 patients with CHD and 155 healthy controls, primarily males, frequency matched for age and gender, using the Food Frequency Questionnaire (FFQ) of the European Prospective Investigation into Cancer and Nutrition. Adherence to MD was estimated from FFQ by the Mediterranean Diet Score (MDS), an index developed by Trichopoulou (2003) ranging from 0 to 9, with higher scores indicating a stricter adherence. Overall dietary variety was computed from FFQ as a count of single food items consumed at least once a month. Associations between MDS or overall dietary variety and coronary status were evaluated by logistic regression models adjusted for BMI, physical activity, smoking, education, and caloric intake; the Odds Ratio (OR) for CHD for each 1.5-point increase in MDS was 0.76 [IC 95% 0.59; 0.98], whereas the OR for CHD for each 15-item increase in dietary variety was 0.62 [IC 95% 0.46; 0.84]. Remarkably, adherence to MD and overall dietary variety were independently associated with a significantly reduced chance of CHD.

Conclusion: Dietary Mediterranean-ness and overall dietary variety exhibit additive cardioprotective effects.

Keywords: Cardiovascular prevention; Coronary heart disease; Dietary variety; Mediterranean diet; Mediterranean diet score; Varied diet.