Beetroot (Dietary Nitrate)

2 studies · 2 supporting · 0 against

Dietary nitrate is converted in the body (via oral bacteria and blood) into nitric oxide, which relaxes and widens blood vessels.

Dose: 300–600 mg

Tested as: beetroot juice providing ~300-600 mg (5-10 mmol) nitrate/day, single dose or daily for up to 12 weeks; some trials used up to ~1000 mg/day

2 studies · 1 supporting · 1 against

Nitrate-derived nitric oxide reduces the oxygen cost of submaximal exercise and improves muscle contraction efficiency, extending time to exhaustion.

Dose: 300–600 mg

Tested as: beetroot juice or nitrate salts providing ~300-600 mg (5-10 mmol) nitrate, taken acutely 2-3 hours before exercise or daily for 3-15 days; larger umbrella data suggest thresholds of ≥6 mmol/day (~370 mg) for chronic protocols

2 studies · 2 supporting · 0 against

Nitric oxide from dietary nitrate may improve blood flow and modulate pain sensitivity during recovery, without necessarily reducing the underlying muscle-fiber damage.

Dose: 300–500 mg

Tested as: beetroot juice providing ~300-500 mg nitrate/day, typically started before and continued for several days after strenuous/eccentric exercise

2 studies · 0 supporting · 2 against

How it was tested: No change in cognitive function composite score or cerebral blood flow over 13 weeks at any dose.

Proposed nitric-oxide-mediated increase in cerebral blood flow, which would be expected to support attention and processing speed if the mechanism translated into cognitive benefit.

Dose: 45–140 mg

Tested as: same trials as above: acute chewable beetroot tablets (45-82.5 mg nitrate, with vitamin C/betaine) and 13-week pure beetroot juice (70-140 mL/day) in older adults

2 studies · 0 supporting · 1 against

How it was tested: 13 weeks of nitrate-rich beetroot juice, at any of three incremental doses, did not change cognitive function or cerebral blood flow versus a nitrate-depleted placebo in overweight/obese older adults.

Proposed to work via nitric-oxide-mediated increases in cerebral blood flow, though direct evidence for this pathway improving memory in humans is thin.

Dose: 45–140 mg

Tested as: acute trial: chewable tablets with 45-82.5 mg nitrate PLUS 200 mg vitamin C and 100 mg betaine (not nitrate alone); chronic trial: pure beetroot juice, 70-140 mL/day (up to ~2x70 mL) for 13 weeks in older adults

1 study · 0 supporting · 1 against

How it was tested: One week of nitrate-rich beetroot juice did not change soluble adhesion markers or inflammatory cytokines in treated hypertensive adults, despite 3- to 8-fold increases in plasma/salivary nitrate and nitrite.

Proposed to reduce inflammation via nitric-oxide-mediated suppression of endothelial adhesion molecule expression, based on cell and animal data.

Dose: 300–400 mg

Tested as: nitrate-rich beetroot juice providing ~300-400 mg nitrate/day for 1 week, versus nitrate-depleted beetroot juice placebo