Hyperhomocysteinemia and alternate vitamin supplementation

Background: Treatment with folic acid and vitamin B 12 appears to be effective in lowering total plasma Homocysteine (tHcy) concentration, but whether vitamin B 12 alone decreases tHcy in patients with normal vitamin B 12 status is still unknown. The aims of the present study were to explore the effect of alternate vitamin supplementation with folic acid or vitamin B 12 on tHcy concentrations in haemodialysis (HD) patients, and to compare changes in tHcy concentrations with MTHFR genotype.

Methods: 74 patients, 44 men and 30 women, were recruited and randomized blindly into two groups of 37 subjects each. The first group was initially treated with vitamin B 12 for two months, and with folic acid for the following two months; the second group was supplemented in the reverse order. In both groups the treatment was followed by a 2-month washout period. tHcy levels were measured at the beginning of treatment (T0), after two months (T1), four months (T2), and at the end of the washout period (T3). Vitamin B 12 and folate were taken at T0 and T3.

Results: The genotype frequency was: C/C 37%, C/T 34%, T/T 29%. tHcy decreased in both groups following the alternate vitamins therapy. This decrease was greater for the T/T genotype (p<0.05) and was more significant when the treatment start-ed with folic acid (p<0.01). Moreover, after the washout period, tHcy increased remarkably without significant differences between diffusive and convective techniques. Folate levels at the end of study appeared to be reduced in haemodialysis patients. Vitamin B 12 concentration significantly increased in patients on diffusive haemodialysis, confirming the fundamental role of membrane performance.

Conclusions: The alternate vitamin treatment demonstrated the importance of folate therapy and the secondary contribution of vitamin B 12 in lowering tHcy in HD patients.