Effects of Riceberry rice bran oil supplementation on oxidative stress, cardiovascular risk biomarkers, and cardiac autonomic nervous system activity in older adults with prehypertension

Background In this study, we aimed to measure the changes in the biomarkers of oxidative stress, cardiovascular disease risk, and the activity of the cardiac autonomic nervous system in older adults with prehypertension after supplementation with Riceberry rice bran oil. Methods In total, 35 women aged 60–76 years with prehypertension were randomly allocated to two groups, one of which was supplemented with rice bran oil ( n = 18) and the other with Riceberry rice bran oil ( n = 17) at 1,000 mg (500 mg × 2 capsules) daily for 8 weeks. The primary outcomes, including oxidative stress and cardiovascular risk biomarkers, and secondary outcomes, including heart rate variability and blood pressure, were determined before and after the 8-week supplementation. Results The levels of plasma malondialdehyde, blood glutathione disulfide, and tumor necrosis factor-alpha were significantly decreased, and the ratio of reduced glutathione to glutathione disulfide significantly increased in both groups after supplementation (all p < 0.05). No significant differences were noted between groups. Heart rate variability and blood pressure were not statistically significantly different after supplementation in both groups. Conclusions Supplementation with Riceberry rice bran oil for 8 weeks may attenuate oxidative stress and inflammation in older adults with prehypertension. The effects of a longer supplementation period or use in hypertensive persons should be further investigated, especially with regard to blood pressure and cardiac autonomic nervous system activity. Trial registration: This trial was registered March 22, 2019 at https://www.thaiclinicaltrials.org as TCTR20190322002.