Association of dietary patterns with insulin resistance and clinically silent carotid atherosclerosis in apparently healthy people

BACKGROUND/OBJECTIVES: Dietary habits are important determinants of individual cardiovascular and metabolic risk. This study investigated the association between dietary patterns and asymptomatic carotid atherosclerosis, defined as the presence of plaques and/or increased intima media thickness, and metabolic biomarkers of insulin resistance, including the homeostasis model assessment of insulin resistance (HOMA-IR) and the trygliceride/high-density lipoprotein (HDL)-cholesterol (Tg/HDL) ratio in a cohort of adults without known diabetes or atherosclerotic cardiovascular disease. SUBJECTS/METHODS: Nine hundred and twenty-nine randomly selected participants were cross-sectionally investigated. Each participant answered a food frequency questionnaire, and underwent high-resolution ultrasonographic evaluation of both carotid arteries. Laboratory blood measurements were obtained in a subsample of 507 participants. RESULTS: A dietary pattern that could be defined as unhealthy (high consumption of soft drinks, fried foods, seed oils, cured meats, butter, red meat and sweets) was identified in 21% of the cohort, whereas 34% of the cohort exhibited a dietary pattern that resembled the Mediterranean diet (high intakes of fruit, milk and cheese, olive oil, vegetables, pasta and bread). Intermediate habits characterized the remaining 45%. After adjusting for age, body mass index (BMI), waist circumference, glycated hemoglobin (HbA(1)c) and hypertension on treatment, the Mediterranean dietary pattern was associated with significantly lower HOMA-IR (beta-coefficient = - 0.51; P= 0.003). After adjusting for gender, BMI and HbA(1)c, the unhealthy dietary pattern was associated with a significantly higher Tg/HDL-cholesterol ratio (beta-coefficient = 0.43; P= 0.006). No significant association was found between dietary patterns and carotid atherosclerosis. CONCLUSIONS: This study suggests that, independent of measures of adiposity, a Mediterranean dietary pattern is associated with lower insulin resistance.