Increasing Nitrate-Rich Vegetable Intake Lowers Ambulatory Blood Pressure in (pre)Hypertensive Middle-Aged and Older Adults: A 12-Wk Randomized Controlled Trial

• Published in: The Journal of nutrition Vol. 151; no. 9; pp. 2667 - 2679
• Main Authors: van der Avoort, Cindy M T, ten Haaf, Dominique S M, Bongers, Coen C W G, van Oorschot, Frederieke, Verdijk, Lex B, van Loon, Luc J C, Hopman, Maria T E
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.09.2021; Oxford University Press; American Institute of Nutrition
• Subjects: Adults; Aged; Beta vulgaris; Blood Pressure; Blood Pressure Monitoring, Ambulatory; cardiovascular health; Consumption; Diet; Dietary intake; dietary intervention; Dietary Supplements; Food intake; Humans; Hypertension; Hypertension - prevention & control; Juices; Middle age; Middle Aged; Nitrates; Nitrites; Older people; prevention; Studies; Sugar beets; Time measurement; Variance analysis; vegetable consumption; Vegetables; ABPM; SBP; FeNO; NO; DBP; vegetable consumption; hypertension; MAP; cardiovascular health; prevention; BP; dietary intervention
• ISSN: 0022-3166; 1541-6100
• DOI: 10.1093/jn/nxab157

Emerging evidence suggests that increasing dietary nitrate intake may be an effective approach to improve cardiovascular health. However, the effects of a prolonged elevation of nitrate intake through an increase in vegetable consumption are understudied. Our primary aim was to determine the impact of 12 wk of increased daily consumption of nitrate-rich vegetables or nitrate supplementation on blood pressure (BP) in (pre)hypertensive middle-aged and older adults. In a 12-wk randomized, controlled study (Nijmegen, The Netherlands), 77 (pre)hypertensive participants (BP: 144 ± 13/87 ± 7 mmHg, age: 65 ± 10 y) either received an intervention with personalized monitoring and feedback aiming to consume ∼250–300 g nitrate-rich vegetables/d (∼350–400 mg nitrate/d; n = 25), beetroot juice supplementation (400 mg nitrate/d; n = 26), or no intervention (control; n = 26). Before and after intervention, 24-h ambulatory BP was measured. Data were analyzed using repeated measures ANOVA (time × treatment), followed by within-group (paired t-test) and between-group analyses (1-factor ANOVA) where appropriate. The 24-h systolic BP (SBP) (primary outcome) changed significantly (P-interaction time × treatment = 0.017) with an increase in the control group (131 ± 8 compared with 135 ± 10 mmHg; P = 0.036); a strong tendency for a decline in the nitrate-rich vegetable group (129 ± 10 compared with 126 ± 9 mmHg; P = 0.051) which was different from control (P = 0.020); but no change in the beetroot juice group (133 ± 11 compared with 132 ± 12 mmHg; P = 0.56). A significant time × treatment interaction was also found for daytime SBP (secondary outcome, P = 0.011), with a significant decline in the nitrate-rich vegetable group (134 ± 10 compared with 129 ± 9 mmHg; P = 0.006) which was different from control (P = 0.010); but no changes in the beetroot juice (138 ± 12 compared with 137 ± 14 mmHg; P = 0.41) and control group (136 ± 10 compared with 137 ± 11 mmHg; P = 0.08). Diastolic BP (secondary outcome) did not change in any of the groups. A prolonged dietary intervention focusing on high-nitrate vegetable intake is an effective strategy to lower SBP in (pre)hypertensive middle-aged and older adults. This trial was registered at www.trialregister.nl as NL7814.