The effect of dietary fiber (oat bran) supplement on blood pressure in patients with essential hypertension: a randomized controlled trial

Background and aims Insufficient dietary fiber (DF) intake is associated with increased blood pressure (BP) and the mode of action is unclear. The intake of DF supplements by participants in previous interventional studies was still far below the amount recommended by the World Health Organization. Therefore, this study aims to explore the effect of supplementing relatively sufficient DF on BP and gut microbiota in patients with essential hypertension. Methods and results Fifty participants who met the inclusion criteria were randomly divided into the DF group (n=25) and control group (n=25). All the participants received education about regular dietary guidance for hypertension. In addition to dietary guidance, one bag of Oat bran (30g/d) supplement (containing DF 8.9g) was delivered to the DF group. The office BP (oBP), 24h ambulatory blood pressure and gut microbiota were measured at baseline and third month. After intervention, the oSBP(P<0.001), oDBP (P<0.028) in the DF group were lower than those in the control group. Similarly, the changes in 24hmaxSBP (P=0.002), 24hmaxDBP (P=0.001), 24haveSBP (P<0.007) and 24haveDBP (P=0.008) were greater in the DF group than the control group. The use of antihypertensive drugs in the DF group was significantly reduced (P=0.021). The β diversity, including Jaccard (P=0.008) and Bray-Curtis distance (P=0.004), showed significant differences (P