Factors affecting blood pressure responses to diet: The vanguard study

To study physiologic factors affecting the blood pressure (BP) response to nonpharmacologic maneuvers, fasting blood glucose, insulin, lipid and miner al levels, urinary mineral excretion, and the calcium regulating hormones p arathyroid hormone (PTH) and 1,25 dihydroxyvitamin D (1,25 (OH)(2)D) were m easured in 71 unmedicated hypertensive (26 hypertensive only [HT], 45 hyper tensive hyperlipidemic [HTHL]), and 87 normotensive hyperlipidemic (NTHL) c ontrol subjects before and during a 10-week multicenter, randomized control led trial comparing a prepared meal plan (CCNW) with a self-selected diet ( SSD) based on nutritionist counseling. Blood pressure fell to a greater extent in hypertensive versus normotensive subjects (-8 +/- 1/-5 +/- 1 v -2 +/- 1/-2 +/- 1 mm Hg, P < .0001/P < .0001 ), and on CCNW versus SSD diets (Delta systolic BP [SBP]/Delta diastolic BP [DBP], P = .033/P = .002). Diet-induced weight change was the strongest co rrelate of changes in BP (SBP: r = 0.360, P < .0001; DBP: r = 0.414, P < .0 001), which, on multivariate analysis for Delta SBP, could partly be accoun ted for by diet-induced changes in fasting glucose (r = 0.215, P = .009) an d cholesterol (r = 0.219, P = .006) levels. Independently of weight, diet-i nduced changes in SEP also were significantly related to concomitant change s in urinary excretion of potassium (r = -0.285, P = .001), magnesium (r = -0.254, P = .003), and calcium relative to sodium (r = -0.200, P = .021), b ut not to sodium per se; and to changes in serum potassium (r = -0.249, P = .002), phosphorus (r = -0.279, P = .001), PTH (r = 0.288, P = .0006), and 1,25 D (r = 0.202, P = .017). We conclude that the ability of diet to lower BP successfully may result fr om the additive contributions of multiple components. Independently of weig ht loss and the associated changes in circulating glucose and cholesterol, BP is influenced by the increasing provision of minerals such as potassium, magnesium, and calcium, perhaps by virtue of their suppressive effects on circulating vasoactive calcium regulating hormones. Am J Hypertens 2000;13: 956-965 (C) 2000 American Journal of Hypertension, Ltd.