The effect of Ocufolin, a vitamin complex composed of L-methylfolate (vitamin B9), vitamin B1, B2, B6, B12, C, D, E, N-acetylcysteine and other compounds (Table 2), on DR was tested by Liu and colleagues in a specific cohort of diabetes subjects with methylenetetrahydrofolate reductase (MTHFR) polymorphisms [29,30]. This evidence concerns the gene MTHFR and diabetes mellitus.