Daily ingestion of 6.0 mmol of dietary nitrate from beetroot juice for six weeks improves endothelial function in untreated hypercholesterolemic adults, increasing flow-mediated dilation by 1.1% (24% improvement from baseline), which is significantly greater than the 0.3% decline observed with placebo, indicating a direct causal effect on vascular health.

When someone eats nitrate-rich beetroot juice, bacteria in the mouth turn the nitrate into nitrite, which gets swallowed and absorbed into the blood. In the bloodstream, nitrite is converted into nitric oxide, which tells blood vessels to relax and widen. This makes blood flow easier and improves how well the inner lining of blood vessels works. Nitric oxide also reduces harmful molecules that would otherwise block its effect.