The effects did not differ by sex or by age group .
Conclusions Evidence on the effects of supplementation of low concentrations of vitamin B12 and folate on haematological parameters in community-dwelling older people is inconclusive .
Background / objectives Low vitamin B12 and folate levels in community-dwelling older people are usually corrected with supplements .
However , the effect of this supplementation on haematological parameters in older persons is not known .
Genomic DNA methylation decreases in response to moderate folate depletion in elderly women.
BACKGROUND Methylation of genomic DNA is dependent on an adequate supply of folate coenzymes . Previous data support the hypothesis that abnormal DNA methylation plays an integral role in carcinogenesis . To date , no studies assessing the effect of inadequate folate status on DNA methylation in older women ( aged > 63 y ) have been reported . OBJECTIVE The effect of moderate folate depletion followed by folate repletion on leukocyte genomic DNA methylation was investigated in elderly women ( aged 60 - 85 y ) to evaluate whether DNA methylation could be used as a functional indicator of folate status . DESIGN Healthy , postmenopausal women ( n = 33 ) consumed a moderately folate-depleted diet ( 118 microg folate/d ) for 7 wk , followed by 7 wk of folate repletion with 200 or 415 microg/d , each provided as 2 different dietary treatments for a total of 4 treatment groups ( n = 30 ) . Leukocyte DNA methylation was determined on the basis of the ability of DNA to incorporate [(3)H]methyl groups from labeled S:-adenosylmethionine in an in vitro assay . RESULTS Incorporation of [(3)H]methyl groups increased significantly ( P : = 0.0025 ) in response to folate depletion , suggesting undermethylation of DNA . No significant changes were detected in [(3)H]methyl incorporation in any group over the 7-wk repletion period compared with postdepletion values . CONCLUSIONS DNA methylation status may be used as a functional indicator of moderately depleted folate status . The slow response to the repletion diets observed suggests that normalization of DNA methylation after moderate folate depletion may be delayed in older women
The effects did not differ by sex or by age group .
Conclusions Evidence on the effects of supplementation of low concentrations of vitamin B12 and folate on haematological parameters in community-dwelling older people is inconclusive .
Background / objectives Low vitamin B12 and folate levels in community-dwelling older people are usually corrected with supplements .
However , the effect of this supplementation on haematological parameters in older persons is not known .