Effect of Dietary Fiber (Oat Bran) Supplement in Heart Rate Lowering in Patients with Hypertension: A Randomized DASH-Diet-Controlled Clinical Trial

(1) Background: The management goal for patients with essential hypertension (HTN) is not only to lower blood pressure (BP), but also to control increased heart rate (HR). In a previous study, it was found that dietary fiber (DF) supplementation can effectively reduce BP in patients with HTN. The aim of this study was to determine whether a DF supplement can lower HR in patients with HTN. (2) Methods: Seventy patients who met the inclusion and exclusion criteria were randomly allocated into the control group (n = 34) and the intervention group (n = 36). The regular DASH dietary care was delivered to both groups of patients. In addition, one bag of oat bran (30 g/d, containing DF 8.9 g) was delivered to the intervention group. The 24 h ambulatory heart rate was measured at baseline and 3 months. (3) Results: At 3 months, the 24 h maximum heart rate (24h maxHR) in the intervention group was significantly lower than that in the control group. After the intervention, within-group comparisons in the intervention group revealed that there were significant reductions in the 24 h average heart rate (24h aveHR), 24h maxHR, average heart rate during day time (D-aveHR), minimum heart rate during day time (D-minHR), and maximum heart rate during day time (D-maxHR). Similar differences were not found in the control group. (4) Conclusions: Dietary fiber (oat bran) supplementation might be beneficial in lowering HR in patients with HTN.