Beetroot / Dietary Nitrate

Kapil et al. (Hypertension, 2015; PMID 25421976): 68 adults with hypertension, half untreated, 4 weeks of nitrate-rich beetroot juice; clinic, ambulatory and home blood pressure fell versus nitrate-free juice; funded by the Medical Research Council and the British Heart Foundation (the review notes the senior author directs a company holding patents on medical uses of inorganic nitrate, which the indexed record does not state). Kerley et al. (Br J Nutr, 2018; PMID 29553033): 20 adults with treated but uncontrolled hypertension, 7 days, 24-hour systolic pressure down 8 mmHg, an independent positive replication. Null: Sundqvist et al. (Am J Clin Nutr, 2020; PMID 32091599), the largest trial, 231 adults with elevated pressure, 300 mg nitrate daily for 5 weeks, no effect on 24-hour systolic pressure; Bondonno et al. (Am J Clin Nutr, 2015; PMID 26135348), 27 treated hypertensives, 1 week, no effect on home or ambulatory pressure despite plasma nitrite up threefold; Fejes et al. (Food Funct, 2024; PMID 38546454), 15 older treated hypertensives, 4 weeks, no effect on vascular function or any blood pressure measure. Pooled: Siervo et al. (J Nutr, 2013; PMID 23596162), 16 crossover trials lasting 2 hours to 15 days, mostly healthy volunteers, systolic pressure 4.4 mmHg lower, acute and very short-term evidence; Ashor et al. (J Hypertens, 2017; PMID 28319596), 13 trials of 1 to 6 weeks, the fall present on clinic readings only and absent on 24-hour and home monitoring; Grönroos et al. (Nutr Metab Cardiovasc Dis, 2024; PMID 39069465), 11 trials in hypertension, clinic systolic pressure 5.3 mmHg lower with low certainty, no effect on diastolic or 24-hour pressure. Grade C: independent trials disagree, the effect is confined to clinic readings in the pooled analyses, and several nulls come from people already on antihypertensive treatment. Not counted in this grade, a different form: lozenges combining nitrite with nitrate-rich plant extracts, sold by one maker under two successive brand names. Zand et al. (Nutr Res, 2011; PMID 21530799): randomized trial, 30 days, plasma nitrite and nitrate rose; authors employed by the maker. Houston et al. (J Clin Hypertens, 2014; PMID 24962851): randomized placebo-controlled crossover, 30 adults with untreated hypertension, one lozenge lowered blood pressure at 20 minutes. Bryan et al. (Am J Med, 2023; PMID 37356641): randomized trial, 524 adults with COVID-19, hospitalization, intensive care or death 1.1 against 1.1 percent, stopped for futility; the lead author is the product's developer.