C677T Methylenetetrahydrofolate Reductase and Plasma Homocysteine Levels among Thai Vegans and Omnivores
Hyperhomocysteinemia (HHcy) in vegetarians and vegans is mainly related to a deficiency in B12. However, a mutation in the MTHFR C677T gene may also contribute to HHcy. Therefore, blood status of Hcy, B12, folate, B6 and MTHFR C677T was studied in 109 Thai vegans and 86 omnivores. Vegans were found to exhibit significantly higher levels of Hcy, with a C677T mutation found to be insignificantly related. A significant decrease in serum folate was found in the CC, CT and TT mutations (12.1ng/mL, 9.33ng/ML and 7.20ng/mL respectively). These findings were not however found in omnivores. While HHcy in Thai vegans was mainly contributed to low B12 levels, a modest contribution was given to the MTHFR C677T mutation.
The sample sizes within this study were found to be relatively small, with no control group employed to ensure a more accurate view of the studies results.
The researchers state that this study may not have yielded a positive link between MTHFR mutations and DS prevalence as they only studied the C677T mutation, with the possibility of the A1298C mutation hence playing an unknown role.
Abnormally, this study found similar readings for CC and CT genotypes across both the case and sample groups.
As this study was based on an Indian population, the high prevalence of vegetarians found in this ethnicity may also play a causative role in the development of DS in offspring.
A dietary deficiency in B12 will decrease methylation even in the absence of a MTHFR mutation, as the pathway does not have sufficient nutritional support to full function. Therefore, the spread of MTHFR 677 genotypes may be evenly spread across this population sample, but may not provide clear evidence, as even those with a health C677C genotype may be undermethylating.