Relation of raw and cooked vegetable consumption to blood pressure: the INTERMAP Study

Abstract

Inverse associations have been reported of overall vegetable intake to blood pressure (BP); whether such relations prevail for both raw and cooked vegetables has not been examined. Here we report cross-sectional associations of vegetable intakes with BP for 2195 Americans ages 40-59 in the International Study of Macro/Micronutrients and Blood Pressure (INTERMAP) using four standardized multi-pass 24-h dietary recalls and eight BP measurements. Relations to BP of raw and cooked vegetables consumption, and main individual constituents were assessed by multiple linear regression. Intakes of both total raw and total cooked vegetables considered separately were inversely related to BP in multivariate-adjusted models. Estimated average systolic BP differences associated with two s.d. differences in raw vegetable intake (68 g per 1000 kcal) and cooked vegetable intake (92 g per 1000 kcal) were -1.9 mm Hg (95% confidence interval (CI): -3.1, -0.8; P=0.001) and -1.3 mm Hg (95% CI: -2.5, -0.2; P=0.03) without body mass index (BMI) in the full model; -1.3 mm Hg (95% CI: -2.4, -0.2; P=0.02) and -0.9 mm Hg (95% CI: -2.0, 0.2; P=0.1) with additional adjustment for BMI. Among commonly consumed individual raw vegetables, tomatoes, carrots, and scallions related significantly inversely to BP. Among commonly eaten cooked vegetables, tomatoes, peas, celery, and scallions related significantly inversely to BP.

Trial registration: ClinicalTrials.gov NCT00005271.

Figure 1

Mean (a) systolic and (b) diastolic BP (mm Hg) by quartiles of raw vegetable intake (g per 1000 kcal), adjusted for Model 3 covariates for 2195 US participants. Whiskers are 95% confidence intervals. P for trend for (a) P=0.02 and for (b) P=0.003. Quartile cut-offs for raw vegetable intake (g per 1000 kcal) were 7.6 (25th percentile), 20.1 (50th percentile), 37.1 (75th percentile) for men and 11.0, 27.7, 48.1 for women.² Model 3: adjusted for age, gender, sample, education, physical activity, smoking status, history of cardiovascular disease or diabetes mellitus, family history of high BP, use of special diet, use of dietary supplement, urinary sodium, alcohol, polyunsaturated fatty acids, saturated fatty acids, and cholesterol.