Low folate levels combined with a MTHFR C677T mutation are an important cause of high homocysteine levels that are linked with major depressive disorder (MDD). 86 South African patients diagnosed with MDD were studied alongside 97 controls were examined for an interrelationship between these inter-playing factors of methylation.
Results found the folate level to be significantly lower in this group when compared to controls and was correlated with an increased BMI, especially in females. Overall BMI was found to be higher in MDD patients, which was also associated with the MTHFR C677T heterozygous mutation and increased homocysteine levels. Significantly higher homocysteine levels observed in MDD patients therefore appears to be controlled by the effects of the C6577T mutation and low folate intake on BMI. Therefore, this study reinforced the importance of folate ingestion being above recommended intakes for those with altered function of the methylation pathways, as it leads to elevated homocysteine levels that significantly impact on the development of diseases such as MDD.