Twelve RCTs (n=522 patients) were included in the review. Six trials were parallel group double-blind RCTs; six RCTs had a crossover design.
There was a statistically significant reduction in systolic blood pressure in groups receiving folic acid (-2.03mmHg, 95% CI -3.63 to -0.43; eight RCTs, n=293 patients), but the change in diastolic blood pressure was not statistically significant (0.01mmHg, 95% CI -1.12 to 1.13).
There was a statistically significant increase in flow-mediated dilation (1.61%, 95% CI 1.27 to 1.96; eight RCTs, n=372 patients).
There was no evidence of publication bias in either of the analyses.