Dietary fiber and progression of atherosclerosis: The Los Angeles Atherosclerosis Study. Am J Clin Nutr

Background: Several epidemiologic studies found weak protec-tive relations between dietary fiber intake and the risk of cardio-vascular disease events. However, few of the studies addressed possible mechanisms of the effect. Objective: In the present study, we estimated relations between the progression of atherosclerosis and the intake of selective di-etary fiber fractions. Mediation of the relations by serum lipids was also investigated. Design: Participants who were free of heart disease and aged 40–60 y were recruited into the cohort (n 573; 47 % women). The intima-media thickness (IMT) of the common carotid arteries was measured ultrasonographically at the baseline examination and at 2 follow-up examinations (n 500), dietary intakes were assessed with six 24-h recalls (3 at baseline and 3 at the first follow-up examination), and blood samples were analyzed at base-line and at both follow-up examinations. Results: A significant inverse association was observed between IMT progression and the intakes of viscous fiber (P 0.05) and pectin (P 0.01). Correction for measurement error increased the magnitude of these estimated effects. The ratio of total to HDL cholesterol was inversely related to the intakes of total fiber (P 0.01), viscous fiber (P 0.05), and pectin (P 0.01). The magnitude of the association between IMT progression and the intakes of viscous fiber and pectin was attenuated by adjustment for serum lipids. Conclusions: The intake of viscous fiber, especially pectin, appears to protect against IMT progression. Serum lipids may act as a medi-ator between dietary fiber intake and IMT progression. Am J Cli