Association between changes in plant protein and mineral intakes and blood pressure as part of a dietary portfolio: a randomized controlled trial

Background Combining foods with lipid‐lowering properties (“dietary portfolio”) lowers blood pressure [BP]. Objective To determine associations between dietary portfolio components and BP. Methods Parallel substudy (n=97) with hyperlipidemia from 2 Canadian academic centers (Toronto and Vancouver). Participants received dietary advice on either a low‐saturated fat therapeutic diet (control) or a dietary portfolio emphasizing plant sterols, soy protein, viscous fibers, and nuts. Dietary portfolio counseling was delivered over 6 months at 2 intensities: “routine” (2 clinic visits); and “intensive” (7 visits). Results Mean systolic blood pressure [SBP] fell 2.7 mmHg (95% CI: 0.3 to 5.6) on the intensive portfolio (n=29), 4.4 mmHg (1.3, 6.4) on the routine portfolio (n=31), and 0.5 mmHg (−3.1, 2.0) on the control (n=37). Diastolic blood pressure [DBP] fell 2.0 (0.3 to 4.7), 2.3 (0.7 to 3.9), and 1.0 mmHg (−2.6 to 0.6), respectively. The dietary portfolio reduced SBP and DBP compared with control (P<=0.021). Increased plant protein intake (%) correlated with reductions in SBP (r=−0.224, p=0.027) and DBP (r=−0.238, p=0.019), as did increased magnesium (%) (SBP: r=−0.169, p=0.048; DBP: r=−0.243, p=0.004). Changes in potassium and sodium intakes were not associated with BP changes. Conclusion Higher plant protein and magnesium intakes were associated with favourable changes in BP. Primary funding: CIHR.