A Randomized Controlled Trial of the Effects of Dietary Nitrate Supplementation on Blood Pressure, Exhaled Nitric Oxide Level and Maximal Isometric Handgrip Strength in Pre-hypertensive Women

• Published in: Lecture Notes in Bioengineering
• Main Author: Linoby A.; Azrin A.A.; Adnan M.A.; Za’don N.H.A.; Sariman M.H.; Mohd Nasir M.Z.; Raja Hussain R.N.J.
• Format: Book chapter
• Language: English
• Published: Springer 2020
• Online Access: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85089570435&doi=10.1007%2f978-981-15-3270-2_41&partnerID=40&md5=a0fd9b9c21b3dd8512bc73ea66f14391

It is still not known whether dietary nitrate can improve blood pressure (BP) and muscular strength in prehypertensives women. The current study investigated the effects of chronic (14-day) nitrate-rich beetroot extract supplementation on the blood pressure responses, maximal isometric handgrip strength and breath nitric oxide level in pre-hypertensive women. In a double-blind, randomized, crossover design, 9 prehypertensives females completed all assessments at pre-supplementation (as control; PRE) and 2-h after orally consumed beetroot extract (BRE; 250 mg·kg−1·day−1) and placebo (PLA; red coloring powder with negligible NO3− and NO2− content), with a washout period of 10 days separating each trial. BRE reduced systolic blood pressure (BRE: 126 ± 2.2 vs. PLA: 132 ± 4.0 vs. PRE: 131 ± 3.2 mmHg; P < 0.05). Similarly, diastolic blood pressure (BRE: 80 ± 4.6 vs. PLA: 84 ± 4.5 vs. PRE: 82 ± 4.4 mmHg; P < 0.05) and mean arterial pressure (BRE: 95 ± 3.5 vs. PLA: 100 ± 3.7 vs. PRE: 98 ± 3.4 mmHg; P < 0.05) were all lowered following BRE supplementation. However, no statistically significant changes were observed in maximal isometric handgrip strength across the trial condition. Additionally, resting fractional exhaled nitric oxide was elevated by ~124% and ~138% compared to the PRE and PLA condition, respectively (both P < 0.05). These findings suggest chronic (14-day) beetroot extract supplementation can significantly improve BP indices in the high-normal BP (prehypertension) population, but not handgrip strength. © 2020, Springer Nature Singapore Pte Ltd.