Abstract P337: Dietary Intakes of Rice, Bread, Pasta, Potatoes and Blood Pressure: The International Study of Macro/Micro-nutrients and Blood Pressure (INTERMAP)

Abstract

Background: Previous population-based cross-sectional studies have reported modest inverse relations of dietary starch intake and blood pressure (BP). However, studies that have evaluated associations of BP with starchy foods, e.g., rice, potatoes, pasta, bread, are limited. Objective: Data from INTERMAP were used to assess relations between consumptions of starchy foods and BP. Methods: INTERMAP is a cross-sectional epidemiologic study of 4,680 persons ages 40 to 59 years from 17 random population samples in China, Japan, United Kingdom (UK), and United States of America (USA). BP was measured 8 times; data on food and supplement use were obtained from 4 standardized in-depth multi-pass 24-hour dietary recalls and 2 timed 24-hour urine collections. Differences in BP for each food intake higher by two standard deviations (SD) were estimated by multivariable linear regression (2 SD values: rice: 177, pasta: 56, potatoes: 65, bread: 40, sum of these four: 177 g/1,000 kcal). Adjustment for possible confounders was performed sequentially; for age, gender, sample; plus dietary and other lifestyle factors. Results: Rice intake higher by 2SD was associated with systolic/diastolic BP differences of -1.38 /-0.79 mm Hg (p <0.05 and p = 0.08) adjusted for age, gender, and sample. After further adjustment for dietary and other lifestyle factors, these associations were attenuated to -0.36 mm Hg for systolic BP (p = 0.61) and -0.28 mm Hg for diastolic BP (p = 0.55). Cross-country heterogeneity was detected for the associations between rice intake and systolic BP: inverse for Japan, China, and USA; direct for UK. Consumption of other starchy foods were not significantly associated with BP. After adjustment for age, gender, and sample, 2SD difference for the sum of these 4 starchy foods was associated with significant systolic/diastolic BP differences of -1.17/-0.84 mm Hg (p <0.05 for both); associations were not significant with adjustment for dietary and other lifestyle factors. Conclusions: Modest inverse associations were observed with BP and intake of rice and the sum of the four most common starchy foods in four countries. Higher consumption of these starchy foods may contribute modestly to lower blood pressure levels in other populations, and thereby potentially confer preventive benefits regarding hypertension and cardiovascular disease.