Folate status of elderly women following moderate folate depletion responds only to a higher folate intake

Dietary Reference Intakes (DRI) for folate for elderly women have been base d primarily on data extrapolated from studies in younger women. This study was conducted to provide the first age-specific data in elderly women (60-8 5 y) from a controlled metabolic study on which to base folate intake recom mendations. Subjects (n = 33) consumed a moderately folate-deplete (118 mu g/d) diet for 7 wk, followed by repletion diets providing either 200 or 415 mu g folate/d as diet plus folic acid (FA) or a combination of FA and oran ge juice (OJ) for 7 wk (n = 30). Comparisons among and within groups were m ade for serum folate (SF), RBC folate and plasma total homocysteine (tHcy) concentrations. SF concentrations decreased significantly (P < 0.001) durin g depletion (65 +/- 15%). Postrepletion, the adjusted SF concentration for subjects consuming 415 mu g folate/d was significantly greater (P = 0.003) than for subjects consuming 200 mu g folate/d. RBC folate concentrations de creased (P < 0.001) during depletion (21 +/- 10%) and further (P < 0.001) d uring repletion (5 +/- 14%). During depletion. plasma tHcy concentrations i ncreased significantly (P < 0.001) and an inverse relationship between SF a nd plasma tHcy concentrations was observed in 94% of subjects (P < 0.001). Reversal of this inverse relationship was significant only for subjects con suming 415 mu g folate/d (P < 0.001). Postrepletion, subjects consuming 200 mu g folate/d had a significantly higher (P = 0.009) adjusted plasma tHcy concentration than subjects consuming 415 mu g folate/d. These data in elde rly women indicate that 415 mu g/d folate, provided as a combination of die t, FA and OJ, or diet and FA, normalizes folate status more effectively tha n does 200 mu g/d, thus providing age-specific data for future folate intak e recommendations.