Dietary nitrate (beetroot)

Dietary nitrate (NO₃⁻) is abundant in beetroot, leafy greens, and celery. Your body converts it to nitric oxide (NO) in a two-step cascade. First, your salivary glands concentrate circulating nitrate, and bacteria on the back of your tongue reduce it to nitrite (NO₂⁻). The nitrite is then absorbed and further reduced to NO in your blood and tissues, especially where oxygen is low, like in working muscle and ischemic blood-vessel walls. This 'entero-salivary' pathway is separate from the classic eNOS route. And it matters more as your eNOS activity declines with age (Lundberg, Weitzberg & Gladwin 2008). Kapil et al. (2015) ran a randomized double-blind trial. 250 ml of nitrate-rich beetroot juice daily for four weeks cut systolic blood pressure by about 8 mmHg and diastolic by about 4 mmHg in adults with hypertension, with no significant side effects. Bailey et al. (2009) found that six days of beetroot juice cut the oxygen cost of moderate cycling by about 19% and extended time to exhaustion. The proposed reasons: more efficient mitochondria and a lower ATP cost of muscle contraction. The oral microbiome is essential here. An antibacterial mouthwash that wipes out the nitrate-reducing bacteria nearly abolishes the nitrite rise and the blood-pressure effect. So antibiotics and oral-hygiene products directly change how well it works. In humans, the evidence is strongest for acute blood-pressure lowering and exercise economy in non-elite people. Effects on all-cause death and longevity remain unproven in controlled trials.

Last reviewed: June 22, 2026

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