Background:
The color of the edible portion of fruits and vegetables, reflecting the presence of pigmented phytochemicals, may be used as an indicator of their nutrient profile. Previous cohort and intervention studies have documented beneficial associations of fruits and vegetables with blood pressure (BP). However, whether the color of fruits and vegetables is associated with BP is unknown.
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 measurements and four 24-hr dietary recalls were completed. Fruits and vegetables were categorized in 4 color groups: green, orange/yellow, red/purple, and white. BP regression coefficients per 2SD higher intake were estimated using multivariable linear regression models. To estimate overall associations, 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 medication (antihypertensive, cardiovascular or for diabetes), body mass index, and intake of low-fat dairy, fibre-rich grain products, red and processed meats, fish and shellfish, and mutually for other fruit and vegetable color groups.
Results:
Average daily fruit plus vegetable intakes (g/1000 kcal) was 183 in the total population, varying from 129 in the United Kingdom to 222 in China. White fruits and vegetables contributed 32% of total fruit and vegetable intake, orange/yellow 27%, green 26%, and red/purple 15%. Fruit and vegetable color groups were weakly related to each other, partial r values ranged from 0.08 for green with red/purple to 0.15 for white with orange/yellow.
Fruit and vegetable color groups were highly correlated with dietary and urinary potassium; highest correlation coefficients were for white fruits and vegetables (r=0.46 for dietary and r=0.26 for urinary potassium). Green fruits and vegetables were also highly related to beta-carotene (r=0.40) and dietary fiber (r=0.40), orange fruits and vegetables to vitamin C (r=0.59), and white fruits and vegetables to dietary fibre (r=0.49).
Green fruit and vegetable intake higher by 90 g/1000 kcal was associated with a systolic BP difference of -1.19 mm Hg (P<0.05). Green fruits and vegetables comprised mainly green vegetables including: cabbages (52%), lettuces (21%), dark leafy (10%), and a heterogeneous group (17%). Other fruit and vegetable color groups and total fruits plus vegetables were not associated with BP.
Conclusion:
Higher intake of green fruits and vegetables may contribute to lower systolic BP.
Association between overall fruit and vegetable intake, and fruit and vegetable sub-types and blood pressure: the PRIME study
