Impacts of oral supplementation of vitamin B12 and plasma levels of homocysteine on progression and survival in a Chinese ALS cohort.

Objective: We investigate the impact of plasma levels of folate, vitamin B12 (VB12), homocysteine (HCY) and oral supplementation of folate and VB12 on amyotrophic lateral sclerosis (ALS) progression and survival.

Methods: Patients with sporadic ALS were consecutively enrolled and regularly followed up. Oral supplementation of folate and VB12 was recommended to all involved patients. Tests of plasma levels of folate, VB12 and HCY were conducted before or after medication.

Results: A total of 120 sporadic ALS patients with results of plasma folate, VB12 or HCY were finally included. Oral supplementation of VB12 significantly increased the plasma levels of folate (p < 0.01) and VB12 (p < 0.01), and lower HCY (p < 0.001). The progression rate of ALS patients in the first 3-6 months was negatively related to the plasma level of VB12 (p = 0.008). After taking VB supplements, the progression rate in the first 3-6 months was comparable to previous progression rate (p = 0.102) and significantly lower than that in the 9-12 month follow-up (p < 0.01). There was no significant difference in survival time between the two groups that took VB12 and those who did not take it neither between patients with high and low serum levels of folate, VB12 or HCY.

Conclusion: Oral intake of VB12 supplements may significantly increase plasma levels of folate and VB12 and decrease plasma levels of HCY in ALS patients. Oral supplementation of folate and VB12, and subsequent high levels of VB12 in serum, may lower the ALS progression at the early stages but show no significant impact on ALS survival time.