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

Abstract

Poor iron status affects 50% of Indian women and compromises work productivity, cognitive performance, and reproduction. Among the many strategies to reduce iron deficiency is the commercial fortification of iodized table salt with iron to produce a double-fortified salt (DFS). The objective of this study was to test the efficacy of DFS in reducing iron deficiency in rural women of reproductive age from northern West Bengal, India. The participants were 212 women between 18 and 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 μg/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 log10 μg/L), soluble transferrin receptor (−0.59 mg/L), and body iron (+1.43 mg/kg), with change in status analyzed by general linear models controlling for baseline values. This study demonstrated that DFS is an 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.

Performance Factors Influencing Efficacy and Effectiveness of Iron Fortification Programs of Condiments for Improving Anemia Prevalence and Iron Status in Populations: A Systematic Review

“…As presented in Table 1, the most tested condiment, as a vehicle for efficacy or effectiveness of iron fortification, was salt. This fortification approach included 13 Double-fortified Salt (DFS) [21][22][23][24][25][26][27][28][29][30][31][32][33] and five Multiple Micronutrient Fortified Salt (MMFS) studies [34][35][36][37][38]. Only one study evaluated a seasoning powder [39], two studies evaluated fish sauce [40,41], and two studies evaluated soy sauce [42,43].…”

“…There were no efficacy or effectiveness studies of iron-fortified bouillon cubes. All studies were conducted in Asia or Africa using as subjects children or women of reproductive age during different time lengths using as fortificants a variety of iron forms that included micronized ground ferric pyrophosphate [21,30,33,38], encapsulated ferrous fumarate [21,31], ferrous fumarate [22], ferrous sulfate [23,28], microencapsulated ferrous fumarate [24], unknown iron source [25][26][27], ferrous sulfate monohydrate chelated with malic acid and sodium hexametaphosphate [29], ferrous sulfate hydrate encapsulated with partially hydrogenated vegetable oil [32], chelated ferrous sulfate [34][35][36][37], H-reduced elemental iron encapsulated with partially hydrogenated vegetable oil [39], ferrous sulfate citrate [40], or NaFeEDTA [40][41][42][43]. Blood hemoglobin was the main hematological indicator in all studies to evaluate the effect of iron fortification.…”

“…Two studies reported environmental conditions, such as the presence of malaria and parasitism, as factors influencing the outcomes negatively [27,30]. Two other reported deficiencies of micronutrients such as folate and vitamin B12 as possible causes for not attaining a significant reduction in anemia prevalence [24,30]. On the other hand, three of these studies did not reach statistical significance in one or more iron parameters possibly due to statistical issues such as an uneven balance in the prevalence of anemia between experimental and control group at baseline or increases on iron parameters in control groups at the end of the interventions [22,35,37].…”

“…The full quality assessment table can be seen in Supplementary Materials Table S1. There were n = 12 studies classified as strong [21,24,[30][31][32][33]35,[38][39][40][41][42], n = 7 studies classified as moderate [22,26,28,29,36,37,43], and n = 4 studies classified as weak [23,25,27,34].…”

“…Effects sizes were estimated for each study, disaggregated by gender, age, iron source, and/or iron concentration when possible (Figure 2). Effect sizes were considered negligible if the standard deviation crossed the 0 x-axis, which was seen in nine studies [22,24,26,27,31,34,36,39,42]. Interestingly, Rajagopalan et al [26] demonstrated a negligible effect size for men, but a positive effect size for women, indicating that double-fortified salt may be a more effective treatment for women than men.…”