Centre for Vision Research, Department of Ophthalmology and Westmead Millennium Institute and Physical Activity, Nutrition and Obesity Research Group, University of Sydney, Sydney, New South Wales, Australia; Faculty of Health and Behavioural Sciences, University of Wollongong, Sydney, New South Wales, Australia; University of Sydney Clinical School, Children's Hospital at Westmead, Sydney, New South Wales, Australia; School of Medicine and Public Health, University of Newcastle, Newcastle, New South Wales, Australia.
We aimed to prospectively examine the association between the glycemic index and glycemic load of foods consumed and the dietary intakes of carbohydrates, sugars, fiber, and principal carbohydrate-containing food groups (eg, breads, cereals, and sugary drinks) with changes in blood pressure during adolescence. A total of 858 students aged 12 years at baseline (422 girls and 436 boys) were examined from 2004-2005 to 2009-2011. Dietary data were assessed from validated semiquantitative food frequency questionnaires. Blood pressure was measured using a standard protocol. In girls, after adjusting for age, ethnicity, parental education, parental history of hypertension, baseline height, baseline blood pressure, change in body mass index, and time spent in physical and sedentary activities, each 1-SD (1-SD=7.10 g/d) increase in baseline dietary intake of total fiber was associated with a 0.96-, 0.62-, and 0.75-mmHg decrease in mean systolic (P=0.02), diastolic (P=0.01), and arterial blood pressures (P=0.002), respectively, 5 years later. In girls, each 1-SD increase in dietary glycemic index, glycemic load, carbohydrate, and fructose was concurrently related to increases of 1.81 (P=0.001), 4.02 (P=0.01), 4.74 (P=0.01), and 1.80 mm Hg (P=0.03) in systolic blood pressure, respectively, >5 years. Significant associations between carbohydrate nutrition variables and blood pressure were not observed among boys. Excessive dietary intake of carbohydrates, specifically from high glycemic index/glycemic load foods, could adversely influence blood pressure, particularly in girls, whereas fiber-rich diets may be protective against elevated blood pressure during adolescence.