Low serum folic acid levels in a nursing home population: a clinical experience.

Four hundred fifty-five residents of the Wisconsin Veterans Home had fasting serum specimens obtained for folic acid as part of standard practice. Twenty-nine percent were taking folic acid supplements. Six percent (n = 28) were taking phenytoin, a folate antagonist. No resident receiving a folate supplement (400 mcg/day) had a low serum folic acid level. This finding may be important for practitioners selecting a dose of folic acid for nursing home patients. Of the 325 residents not receiving a folate supplement, nine (3%) had low folic acid levels (< 2.5 ng/mL). Two of the nine were receiving phenytoin. Five were characterized by staff as eating well. As low serum levels are preventable with a multivitamin, we believe that supplementation with a multivitamin containing 400 mcg folic acid/day should be considered in nursing home residents.