Telomere dynamics: the influence of folate and DNA methylation.

Since the suggestion of their existence, a wealth of literature on telomere biology has emerged aimed at solving the DNA end-underreplication problem identified by Olovnikov in 1971. Telomere shortening/dysfunction is now recognized as increasing degenerative disease risk. Recent studies have suggested that both dietary patterns and individual micronutrients--including folate--can influence telomere length and function. Folate is an important dietary vitamin required for DNA synthesis, repair, and one-carbon metabolism within the cell. However, the potential mechanisms by which folate deficiency directly or indirectly affects telomere biology has not yet been reviewed comprehensively. The present review summarizes recent published knowledge and identifies the residual knowledge gaps. Specifically, this review addresses whether it is plausible that folate deficiency may (1) cause accelerated telomere shortening, (2) intrinsically affect telomere function, and/or (3) cause increased telomere-end fusions and subsequent breakage-fusion-bridge cycles in the cell.