Replacing carbohydrates with monounsaturated fatty acids does not reduce blood pressure
Substituting diets high in carbohydrates with those high in monounsaturated fatty acids (MUFAs) in the context of low saturated fatty acids do not appear to yield favourable effects on blood pressure, according to a meta-analysis.
Researchers conducted a systematic review of randomized controlled trials evaluating the effect of a >3-week intervention of high-MUFA diets in isocaloric substitution for high-carbohydrate diets on systolic blood pressure (SBP) and diastolic blood pressure (DBP). A total of 14 trials representing 980 participants were included in the meta-analysis.
Pooled data, performed using the generic-inverse variance method, revealed that the high-MUFA diets in isocaloric substitution for high-carbohydrate diets did not result in a greater reduction in blood pressure (SBP: mean difference [MD], −0.08 mm Hg; 95 percent CI, −1.01 to 0.84; p=0.86; DBP: MD, 0.01 mm Hg; −0.73 to 0.75; p=0.98).
Dose-response analysis showed neither linear nor nonlinear associations between increasing dose of MUFA substitution for carbohydrates and blood pressure outcomes.
Visual inspection of funnel plots revealed no evidence of a publication bias. This was confirmed by Egger’s and Begg’s tests, which showed no significant small-study effects for either SBP or DBP. The overall quality of the evidence was assessed as moderate.
According to researchers, the analysis may be considered surprising, given that current dietary cardiovascular disease recommendations indicate a 1-unit reduction in SBP in adults with BP ranging 120–159/80–95 mm Hg after replacing 10 percent of energy intake from carbohydrates with MUFA.
Researchers recommend that future meta-analyses consider adopting the individual participant data approach. Additional high-quality substitution trials focusing on carbohydrate quality and considering higher MUFA (%E) target are also needed.