Double-Fortiﬁed Salt Is Efﬁcacious in Improving Indicators of Iron Deﬁciency in Female Indian Tea Pickers 1–3

Poor ironstatus affects 50%ofIndian women andcompromisesworkproductivity, cognitive performance,and reproduction. Among the manystrategies toreduce irondeﬁciency is the commercial fortiﬁcation of iodized table salt with ironto producea double-fortiﬁed salt (DFS). The objective of this study was to test the efﬁcacy of DFS in reducing iron deﬁciency in rural womenofreproductive agefromnorthernWest Bengal, India. Theparticipantswere212womenbetween18and 55 y of age who worked as full-time tea pickers on a large tea estate. Participants in the randomized, controlled, double-blind study were assigned to use either DFS or a control iodized salt for 7.5 to 9 mo. The DFS was fortiﬁed with 3.3-mg ferrous fumarate (1.1-mg elemental iron) per kg of iodized salt, whereas the control salt contained only iodine (47 mg/kg potassium iodate), and both salt varieties were distributed gratis to the families of participants at 0.5 kg/mo for each 2 household members. At baseline, 53% of participants were anemic (hemoglobin <120 g/L), 25% were iron deﬁcient (serum ferritin <12 m g/L), and 23% were iron-deﬁcient anemic. Also, 22% had a transferrin receptor concentration >8.6 mg/L and 22% had negative (<0.0 mg/kg) body iron stores. After 9 mo the participants receiving DFS showed signiﬁcant improvements compared with controls in hemoglobin (+2.4 g/L), ferritin (+0.13 log 10 m g/L), soluble transferrin receptor ( 2 0.59 mg/L), and body iron (+1.43 mg/kg), withchangeinstatusanalyzedbygenerallinearmodelscontrollingforbaselinevalues. This studydemonstratedthatDFSisan efﬁcacious approach to improving iron status and should be further evaluated for effectiveness in the general population. This trial was registered at clinicaltrials.gov as NCT01032005. J. Nutr. 144: 957–964, 2014. control). Covariates that were assessed as potential confounders were diet (vegetarian vs. nonvegetarian), ethnicity (Adivasi vs. Nepali), BMI, MUAC, and socioeconomic indicators. The potential effect of village was assessed by controlling for village as a random factor in a mixed regression model. Because the random effect of village did not have interclass correlation coefﬁcients of 10% or greater, the more parsimonious solution, general linear models (GLMs) with only ﬁxed effects, was used. Plausibility analysis included assessment of potential to beneﬁt over the continuous range of iron status measures. Participants with more severe iron deﬁciency were expected to show a greater change in iron status indicators than participants with less severe or no iron deﬁciency. This was examined through a test of the signiﬁcance of an interaction between the intervention group and baseline iron status that should indicate a signiﬁcantly greater change of iron indicators in the DFS group because of iron fortiﬁcation compared with controls. A second plausi- bility analysis assessed the dose response of DFS by associating the amount of iron consumed from DFS with the change in iron status indicators while controlling for baseline iron status. Participants who consumed higher amounts of DFS throughout the study period were expected to exhibit a greater change in iron status indicators than participants who consumed smaller amounts of DFS.