The Impact of Inorganic Nitrate on Endothelial Function: A Systematic Review of Randomized Controlled Trials and...

Area of Science:

• Cardiovascular Research
• Endothelial Function
• Nitric Oxide Metabolism

Background:

• Inorganic nitrate is a precursor to nitric oxide (NO), a key regulator of vascular homeostasis.
• Endothelial dysfunction is a significant risk factor for cardiovascular disease.
• The nitrate-nitrite-NO pathway plays a crucial role in maintaining vascular health.

Purpose of the Study:

• To systematically review and meta-analyze the impact of inorganic nitrate on endothelial function.
• To assess changes in flow-mediated dilation (FMD) following inorganic nitrate consumption compared to control groups.
• To evaluate the clinical relevance of inorganic nitrate for cardiovascular disease prevention.

Main Methods:

• Systematic literature search of Medline, Web of Science, and Scopus databases.
• Meta-analysis of 13 randomized controlled trials using a random-effects model.
• Assessment of study quality using the Cochrane risk-of-bias tool.

Main Results:

• Inorganic nitrate consumption was associated with a significant improvement in FMD (SMD 1.48%, P < 0.01), with high heterogeneity observed.
• The beneficial effect on FMD was consistent across varying doses, durations, health statuses, and nitrate types.
• Acute nitrate intake demonstrated a greater FMD response compared to chronic intake.

Conclusions:

• Inorganic nitrate supplementation significantly enhances endothelial function (FMD) by over 1%.
• This improvement represents a clinically relevant magnitude for the prevention of cardiovascular disease.
• While promising, further high-quality research is warranted given the heterogeneity and risk of bias in some studies.