Abstract P193: Relation to Blood Pressure of Total and Individual Components of Dietary Fiber and Sugar: The Intermap Study

Abstract

Background: Epidemiological evidence is limited and inconclusive on the separate contributions of soluble, insoluble fiber and dietary sugars to blood pressure (BP). This population based study examines relations to systolic and diastolic BP (SBP/DBP) of total dietary fiber and sugar and their individual components.

Methods: Cross-sectional data were analysed from the population-based INTERMAP study, including 2,195 participants ages 40 to 59 from the United States. During 4 visits, eight BP readings were recorded and dietary intake was assessed by four in-depth 24-hour dietary recalls. Intakes of fiber and sugars (g/1000 kcal) were averaged over 4 days. In successive models, BP regression coefficients per 2 SD higher intake were estimated using isocaloric, multivariable linear regression with adjustment for multiple possible confounders (non-dietary and dietary), including each of the other individual dietary fiber or sugars.

Results: Average intake (SD; g/1000 kcal) of total fiber was 8.8(3.3); soluble fiber 2.8(1.0); insoluble fiber 5.3(2.2). Average intake (SD; %kcal) of total sugar was 26.7(7.9) and of sucrose, the largest component, 10.8 (5.1). Partial Pearson correlation coefficients were low between total fiber and total sugar (r=0.02), and high between soluble and insoluble fiber (r=0.80). Correlations between fructose and other individual sugars were high only for glucose (r=0.93), low (r<0.15) for other sugars.Total dietary fiber intake higher by 7 g/1000 kcal was associated with SBP lower by 1.7 mm Hg (P=0.01) in an isocaloric model adjusted for lifestyle factors in addition to total sugar (%); this was attenuated with further adjustment for urinary potassium excretion. This association was accounted for by the observed inverse association of insoluble fiber with SBP (-2.0 mm Hg, P=0.04), additionally adjusted for soluble fiber. Inverse associations with SBP were found for dietary galactose (-1.5 mm Hg; P=0.04) and lactose (-2.1 mm Hg;P=0.0006). Intakes of total sugar, fructose, glucose, maltose, and sucrose were not associated with BP in isocaloric models adjusted for lifestyle factors and each of the other individual dietary sugars.

Conclusions: Higher intakes of dietary fiber, especially insoluble fiber, may contribute to lower BP, possibly driven by potassium present in high fiber foods. Total sugar intake was not associated with blood pressure; however, intakes of galactose and lactose may favorably influence blood pressure.