Abstract 2374: Whole Grain Intake in Relation to Lipids, Apolipoproteins, and Lipoprotein Subclasses in a Multi-ethnic Cohort: The Insulin Resistance Atherosclerosis Study
Context: Whole grain intake is inversely associated with LDL-c and the metabolic syndrome, but the relationship of whole grains with other lipid parameters, such as small, dense LDL, is not established. We sought to evaluate the relationship of whole grain intake with lipids, apolipoproteins, and LDL lipoprotein subclasses in a large, multi-ethnic cohort.
Methods: This cross-sectional study evaluated 975 non-diabetic participants in the Insulin Resistance Atherosclerosis Study. Baseline whole grain intake was estimated based on intake of dark breads, cooked cereals, and high-fiber cereals assessed in a validated food frequency questionnaire. Fasting lipid measurements included apolipoproteins and lipoprotein subclasses quantified by NMR spectroscopy. Linear regression models evaluated lipid parameters across quartile of whole grain intake after adjustment for demographics (age, sex, ethnicity, center), anthropometrics (BMI, waist circumference), lifestyle factors (smoking, alcohol intake), dietary factors (total kcal, fruits, vegetables, dietary fats) and lipid-lowering medication use. Additional models included directly measured insulin sensitivity (Si).
Results: The cohort was 56% female, had a mean (SD) age of 54.8 (8.5) years, and was 60% non-white, with a median whole grain intake of .73 servings/day. In adjusted models, there was an inverse association between whole grain intake and LDL-c, Apo-B, Apo-B/Apo-A1 ratio, LDL particle concentration (LDL-p), and small LDL-p (Table⇓). These associations remained significant after adjustment for Si (LDL-c: p=.007; Apo-B: p=.04; Apo-B/Apo-A1: p=.03; LDL-p: p=.03; small LDL-p: p=.03).
Conclusion: Whole grain intake is inversely associated with multiple lipid risk factors, including total and small LDL particle concentration, independent of insulin sensitivity and other confounders. This demonstrates additional mechanisms for the cardioprotective effects of whole grains.