Background: The human body requires folic acid (FA) to produce blood cells, secure cell division, and growth. Moreover, this vitamin is important in the prevention of cardiovascular disease (CVD). Because the results of studies on the use of FA in the prevention of CVD are ambiguous, it seems necessary to conduct further research, which will explain in which cases supplementation is effective.

Aim: To assess the impact of FA supplementation on the coagulation, inflammatory, lipid parameters, and kidney function in subjects with atherosclerosis risk factors, depending on the content of FA in their diet.

Methods: The study enrolled 97 young adult Caucasian individuals (34 males and 63 females) with atherosclerosis risk factors. This population was divided into two groups: A — with low content of FA in the diet (< 40% of reference daily intake) and B — with moderate content of FA in the diet (40–90% of reference daily intake). The participants were asked to take FA in the low-dose of 0.4 mg/24 h for 3 months.

Results: Low-dose FA supplementation resulted in elevation of FA concentrations (79% vs. 75.1%) in the studied groups and, concomitantly, a decrease in homocysteine concentrations (21% vs. 20.3%). Mean level of creatinine decreased after FA supplementation in both groups (0.93 ± 1.1 vs. 0.72 ± 0.15 mg/dL and 0.83 ± 0.16 vs. 0.77 ± 0.15 mg/dL). These differences were statistically significant (p < 0.0001). The difference in mean estimated glomerular filtration rate values before and after FA supplementation was statistically significant in group A (p = 0.002) and on the border of statistical significance in group B (p = 0.06).

Conclusions: FA supplementation has no influence on the coagulation, inflammatory and lipid parameters in subjects with atherosclerosis risk factors depending on the content of FA in their diet. However FA supplementation may have a beneficial effect on kidney function in subjects with low content of FA in the diet.