Folic acid Supplementation Impact on Homocysteine and C-terminal Cross-linking Telopeptides of type I Collagen

Abstract

Objectives: Recent studies have emphasised need for intervention studies to clarify the effect of lowering homocysteine levels with B vitamins on bones. The aim of this randomised double blind study was to determine whether lowering homocysteine with folic acid affect marker of bone resorption - C-terminal cross-linking telopeptides of type I collagen (CTX).  Methods: Healthy women (n=59, aged 45-65y) with slightly elevated homocysteine level (> 10 μmol/L) were randomly assigned to receive either 800 μg/day of folic acid or a placebo. In the double blind placebo controlled trial the levels of homocysteine, red blood cell folate, serum folate and CTX levels were measured at baseline and after 4 months.  Results: At baseline there was no statistically significant difference between the level of observed biochemical parameters in folic acid group and placebo group. As expected, folic acid supplementation significantly increased serum folate (99.77%) and RBC folate (79.54%) in intervention group, while in the placebo group serum folate and RBC folate decreased (8.87% respectively 16.26%). After 4 months of intervention homocysteine level significantly decreased in the intervention group (5.06%) while in the placebo group homocysteine level increased (6.86%). Folic acid treatment did not show statistically significant differences in CTX levels before and after intervention (p=0.359). Statistically significant difference in serum folate, RBC folate and homocysteine level before and after intervention showed greater changes in premenopausal women. Conclusions: Supplementation with folic acid lowered homocysteine level but had no beneficial effect on the marker of bone resorption - CTX.