Raise fiber intake to lower blood pressure Original paper

In this meta-analysis of randomized controlled trials, supplementation with soluble dietary fiber decreased both systolic and diastolic blood pressure.

The effect of supplementation with soluble dietary fiber on systolic and diastolic blood pressure.

A total of 5,985 men and women (average ages of 23–68; average baseline BMI of 21.9–37.7), including adults without known health conditions and adults with dyslipidemia, overweight/obesity, metabolic syndrome, type 2 diabetes/prediabetes, or hypertension.

A meta-analysis of 83 randomized controlled trials was performed. The trials were conducted in Asia (29 trials), North America (23 trials), Europe (22 trials), Oceania (4 trials), South America (4 trials), and Africa (1 trial). The types of soluble dietary fiber used included beta-glucan, inulin, glucomannan, resistant starch, psyllium, and guar gum. The comparators included wheat fiber, wheat bran, pectin, rice, corn flakes, starch, rice flour, maltodextrin, amylopectin, breadcrumbs, cellulose, and no intervention. The daily intake of supplemental soluble fiber ranged from 0.5 to 45 grams. The intervention duration ranged from 3 to 52 weeks.

Subgroup analyses were performed to determine whether the results differed according to the health status of the participants or the type of supplemental soluble fiber.

Supplementation with soluble dietary fiber decreased systolic blood pressure by 1.36 mmHg and diastolic blood pressure by 0.72 mmHg, with the certainty of the evidence rated as moderate for both outcomes.

In subgroup analyses, the effect on systolic blood pressure was statistically significant in trials that recruited participants with diabetes, hypertension, or metabolic syndrome and in trials that administered resistant starch or guar gum, whereas the effect on diastolic blood pressure was statistically significant in trials that recruited participants with hypertension and in trials that administered inulin.

In dose-response analyses, each 5-gram increment in daily soluble fiber intake decreased systolic blood pressure by 0.54 mmHg and diastolic blood pressure by 0.28 mmHg. The greatest reduction in systolic blood pressure was reported to occur at an intake of approximately 15 to 20 grams per day of soluble fiber intake. In contrast, there was an apparent linear dose-response relationship for diastolic blood pressure, in which high soluble fiber intakes (up to at least 45 grams/day) corresponded to greater reductions in diastolic blood pressure.