Folate status of adolescents: effects of folic acid supplementation

This study was designed to determine the folate status of an adolescent population and to demonstrate the effect of folic acid supplementation on subjects with low folate status. In phase one, folate status was evaluated in a biracial sample of 164 adolescents 12 to 15 years old. Socioeconomic, demographic, anthropometric, and 7-day food record data were collected, and serum and erythrocyte folate levels were determined. Thirty-five adolescents considered to have had low folate status 6 months earlier participated in phase two, a 2-month supplementation period and reevaluation. No racial differences were observed in folate status, as indicated by amount of folate in the blood and diet. Boys had significantly (p less than .05) higher folate levels in serum and erythrocytes than did girls. Thirteen percent of the boys and 40% of the girls were folate deficient as judged by amount of erythrocyte folate less than 317 nmol/L (140 ng/mL). The folate-deficient subjects had significantly (p less than .05) lower values of hemoglobin than did the normal subjects. Seventeen percent of the boys and 42% of the girls had folate intakes below the recommended dietary allowance for folate. Supplementation of 400 micrograms folic acid daily for 2 months resulted in significant (P less than .05) increases in serum folate, erythrocyte folate, and hemoglobin values and a decrease in mean corpuscular volume. Evidence of high prevalence of low folate status, positive relationship between erythrocyte folate and hemoglobin, and responses of hemoglobin and mean corpuscular volume to the supplement indicated that folate consumption may not be optimal in some groups of adolescents, especially in girls.