Folic acid fortification of iodized salt improves the folate status of non-pregnant adult Ethiopian females and does not impair their iodine status: a community-based, household-randomized, dose-response trial.
The American Journal of Clinical Nutrition 2025
DOI : 10.1016/j.ajcnut.2026.101204
PubMed ID : 41611087
PMCID :
URL : https://linkinghub.elsevier.com/retrieve/pii/S0002916526000134
Abstract
Folic acid (FA) fortification of cereal grains reduces the prevalence of folate insufficiency among adult females and related neural tube defects (NTDs) in their offspring. However, fortifiable cereal grains have limited reach in many lower-income countries, so additional fortification options need to be developed and evaluated.
This study assessed the effects of folic acid fortification of iodized salt on women's discretionary salt intakes, biomarkers of folate and iodine status, and the occurrence of adverse events.
We conducted a community-based, three-arm, household-randomized dose-response trial among 360 non-pregnant Ethiopian females 18-49 years of age. We delivered iodized salts containing 32 parts per million (ppm) iodine and 99, 36, or 0 ppm FA to households bi-weekly for 26 weeks. We measured participants' fasting red blood cell (RBC) folate, serum folate, homocysteine, thyroglobulin, vitamin B12 biomarkers, glucose, and insulin, and urinary iodine/creatinine ratios before and during the intervention. We quantified participants' salt intakes using weighed food records, and we systematically recorded adverse events.
The overall median (IQR) RBC folate concentration at baseline was 476 (371, 580) nmol/L. Participants' mean usual intakes of study salts (7.8±1.8 g/d) did not differ by study arm (p = 0.58). The final median (IQR) RBC folate concentrations were 1275 (1120, 1521) nmol/L, 1004 (819, 1212) nmol/L, and 468 (366, 596) nmol/L in the respective study arms (all significantly different, p<0.001). There were no group-wise differences in urinary iodine/creatinine ratios, serum thyroglobulin, insulin resistance, or reported adverse events.
FA fortification of salt is an effective and safe method to improve women's folate status and thereby reduce the risk of NTD-affected pregnancies.
This trial was registered on the ClinicalTrials.gov web site (registration number NCT06223854): https://clinicaltrials.gov/study/NCT06223854?term=Transcobalamin%20Deficiency&viewType=Table&rank=4.