Background:
Legumes, including soy foods and beans, are nutrient-dense high-quality sources of vegetable protein. Evidence from prospective cohort studies suggests beneficial associations between legume consumption and cardiovascular diseases, however, little is known about their impact on blood pressure (BP). Our objective was to quantify associations with BP of consumption of soy food, beans, and total legume consumption, each considered separately.
Methods:
We used cross-sectional data from the International Study of Macro-/Micronutrients and Blood Pressure (INTERMAP) on 4,680 men and women ages 40-59 years from Japan, China, United Kingdom, and United States. During four visits, eight BP and four 24-hr dietary recalls were collected. Regression coefficients per 2SD higher soy food, bean, and total legume intake were estimated using multivariable linear regression models. To estimate overall association, country-specific regression coefficients were pooled, weighted by inverse of their variance. Adjustments were for age, gender, sample, intake of total energy and alcohol, 24-hr urinary sodium excretion, smoking, education, dietary supplement use, adherence to any special diet, history of cardiovascular diseases or diabetes, family history of hypertension, use of antihypertensive, cardiovascular, or diabetes medication, body mass index, and intake of low-fat dairy, vegetables, fibre-rich grain products, red and processed meats, fish and shellfish, and mutually for soy foods or beans.
Results:
Average daily legume intakes (g/1000 kcal) were 69 in Asian participants and 19 in Western participants. Soy foods contributed 91% of total legume intake in Asian participants; beans were the main source of legumes (68%) in Western countries.
In Asian participants, high correlation coefficients were found between intake of soy foods and iron (r=0.34), arginine (r=0.34), aspartic acid (r=0.34), phenylalanine (r=0.32), isoleucine (r=0.30), and magnesium (r=0.30). In Western participants, soy foods were related to dietary magnesium (r=0.30) and beans were highly correlated with dietary fiber (r=0.44) and magnesium (r=0.22).
Total legume intake higher by 76 g/1000 kcal (2SD) was associated with a diastolic BP difference of -0.75 mm Hg (P=0.009) in the total population, -0.70 mm Hg (P=0.05) in Asian, and -0.86 mm Hg (P=0.08) in Western participants. In the total population, diastolic BP differences were -0.62 mm Hg for soy foods (P=0.04) and -0.42 mm Hg for beans and peas (P=0.06). With regard to systolic BP, a significant inverse association was found for soy food intake higher by 41 g/1000 kcal in Western participants (-1.78 mm Hg, P=0.05).
Conclusion:
Higher intake of legumes, especially soy foods, was associated with lower BP levels.
Prevalence and Predictors of Undiagnosed Hypertension in an Apparently Healthy Western Indian Population