The effects of daily versus weekly folic acid supplementation on biochemical and functional status of reproductive age women in rural Guatemala

Folic acid (FA) and other micronutrient deficiencies are significant public health problems in Guatemala, particularly in women of reproductive age. These deficiencies have several adverse effects on women and also have potential long-term consequences for their children if deficiencies occur during pregnancy. Wheat flour fortification has been implemented in Guatemala for many years, but it has little impact on rural and indigenous populations where the staple is corn rather than wheat. In that context, weekly FA plus other micronutrient supplementation is an attractive idea for reaching women in poor rural areas and in indigenous regions. There is, however, uncertainty about the efficacy of this regimen in comparison to daily supplementation. This randomized controlled trial (RCT) was conducted to (1) investigate the efficacy of weekly versus daily FA plus other micronutrients supplementation on micronutrient status and depressive symptoms in women of childbearing age and (2) examine the possible interaction of iron with zinc. The RCT involved random assignment of 459 women to 4 groups that received weekly (5000 or 2800mug) or daily (400 or 200mug) FA plus iron, zinc and vitamin B12 for 12 weeks. Generalized linear regression models were used to assess treatment effects. Our findings showed that weekly FA plus other micronutrients are as efficacious as daily supplementation in improving folate metabolic status and depressive symptoms. However, daily is more efficacious than weekly supplementation in improving serum ferritin and vitamin B12. No differences were found among the four groups in hemoglobin (Hb) or serum zinc after the intervention, but Hb improved significantly for anemic women. The addition of zinc did not affect the efficacy of supplements on iron status, but had no impact on zinc status. Findings from our study suggest that weekly FA plus other micronutrient supplementation should be considered as a possible intervention for improving the nutritional status and mental health of women not reached by food fortification interventions. However, other approaches need to be considered to alleviate zinc deficiency.