Impact of folic acid-fortified iodised salt in reproductive-aged women

Neural tube defects (NTDs), such as spina bifida and anencephaly (SBA), are severe conditions that result from incomplete closure of the foetal neural tube during embryogenesis, around day 28 after conception. These conditions lead to significant health issues, including still births, postpartum death and permanent neurological disabilities for survivors. Folic acid (vitamin B9) is crucial for DNA synthesis and proper neural tube closure during early pregnancy. Its deficiency is linked to a higher prevalence of NTDs, with global estimates of 260,000 SBA-affected births annually. The prevalence is disproportionately higher in India, at around 40 to 50 cases per 1,000 births, contributing to stillbirths, elective pregnancy terminations and early childhood deaths.

The study assessed the impact of folic acid-fortified iodised salt on serum folate levels among non-pregnant, non-breastfeeding women aged 18 to 45 years in rural India. The non-randomised controlled trial employed a pre-intervention and post-intervention evaluation design in four rural villages in southern India from July to November 2022, to assess the outcomes of folic acid-fortified iodised salt consumption in 83 participants who consumed the double fortified salt over a period of four months. Participants were recruited through town hall meetings and seminars where the benefits of folic acid in preventing SBA were discussed and where attendees were invited to participate voluntarily after receiving detailed information about the study. Inclusion criteria required participants to be non-pregnant, non-breastfeeding women who agreed to stay in their villages for the study duration and consume only the study salt. Exclusion criteria included pregnancy, breastfeeding, use of folic acid supplements, and certain health conditions, such as severe anaemia, uncontrolled hypertension, HIV infection, or a history of SBA-affected pregnancy.

Daily consumption of folic acid from the fortified iodised salt was approximately 300 µg. After four months, median serum folate concentration increased from 14.6 (IQR: 11.2-20.6) nmol/L at baseline to 54.4 (IQR: 43.5-54.4) nmol/L at the end of the study. This 3.7-fold increase in median serum folate levels was found to be highly significant (P < .001) according to a two-tailed Wilcoxon signed rank test. Strengths of the study included high adherence and a high retention rate but the generalisability of the findings is limited due to the small sample size. Another limitation was the lack of comparison with a control group or groups receiving alternative food vehicles. Despite this, the study provides promising evidence that folic acid-fortified iodised salt could be an effective strategy for increasing folate levels in women of reproductive age, thereby potentially preventing thousands of SBA cases and improving maternal and child health outcomes in India and beyond.