Background: Obese children tend to consume less dietary folate, which is an important cofactor in remethylation of homocysteine to methionine. The deficiency of folate can lead to hyperhomocysteinemia.
Objective: To determine whether folic acid supplementation could reduce plasma homocysteine in obese children.
Material and Method: Obese children, aged 9-15 years with body mass index >median plus 2 SD according to WHO reference, were randomly assigned to 2 groups: receiving either 5 mg folic acid or placebo for 2 months. Fasting homocysteine, creatinine, folate, vitamin B12, insulin, glucose and lipid profiles were taken at baseline and the end of the study. Dietary vitamin B12, folate intake and physical activity were assessed using validated questionnaires.
Results: Fifty obese children (31 boys and 19 girls) took part in the study. Their mean age was 10.9+1.6 years and mean BMI Z-score was 3.41+0.69. After the intervention, plasma homocysteine decreased by 15.75% and 6.99% in the folic acid and placebo group, respectively (mean difference 8.76%; 95% CI: 0.26%, 17.25%, p = 0.044). This divergence was more pronounced in boys and it remained significant after adjusting for baseline homocysteine and other confounders. Subgroup analysis showed a larger magnitude of plasma homocysteine reduction in the low folate group (mean difference 12.24%; 95% CI: 1.39%, 23.09%).
Conclusion: The homocysteine lowering effect of folic acid supplementation was found in obese children, especially in boys and those with low serum folate. Further long-term interventional studies are needed to determine the effects of the lowered plasma homocysteine on the cardiovascular outcomes of obese children. This trial was registered on clinicaltrials.gov (NCT01766310).

Keywords: Folic acid, Homocysteine, Obese, Children, Randomized trial