The effects of 1 egg per day on iron and anemia status among young Malawian children: A secondary analysis of a randomized controlled trial

Authors: WERNER, E.ROCHELLE - University Of California, Davis; ARNOLD, CHARLES - University Of California, Davis; Caswell, Bess; IANNOTTI, LORA - Washington University; LUTTER, CHESSA - Rti International, Usa; MALETA, KENNETH - University Of Malawi; STEWART, CHRISTINE - University Of California, Davis

Submitted to: Current Developments in Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/9/2022
Publication Date: 5/13/2022
Citation: Werner, E., Arnold, C.D., Caswell, B.L., Iannotti, L.L., Lutter, C.K., Maleta, K.M., Stewart, C.P. 2022. The effects of 1 egg per day on iron and anemia status among young Malawian children: A secondary analysis of a randomized controlled trial. Current Developments in Nutrition. 6(6). Article nzac094. https://doi.org/10.1093/cdn/nzac094.
DOI: https://doi.org/10.1093/cdn/nzac094

Interpretive Summary: Infants and young children with diets that are low in micronutrient-rich foods are at risk of iron deficiency anemia. Children in low-income countries such as Malawi are at especially high risk of undernutrition. Adding foods such as eggs to their diets may improve their nutritional status, including iron status and anemia. An egg feeding study was conducted in rural Malawi in which 331 children between 6 and 9 months old were given one egg per day to eat along with their usual diet, and another 329 children followed their usual diet with no additional foods provided. At the beginning of the study, 61% of children in both groups had anemia, and 77% were iron deficient. After six months, when the children were 12 to 15 months old, we found that the children who received eggs had the same prevalence of anemia, mean hemoglobin concentration and other markers of iron status as children who had not received eggs. At the end of the study, 43% of the children had anemia and 89% were iron deficient. These findings took into consideration factors that can affect iron status and anemia, such as malaria or other infections. Other interventions are needed to address the high prevalence of iron deficiency and anemia among young, Malawian children.

Technical Abstract: Young children with diets lacking diversity with low consumption of animal source foods are at risk of iron deficiency anemia (IDA). Our objectives were to determine the impact of supplementing diets with 1 egg/day on: (1) plasma ferritin, soluble transferrin receptor (sTfR), body iron index (BII), and hemoglobin concentrations; and (2) the prevalence of iron deficiency (ID), anemia, and IDA. Methods: Malawian 6-9mo old infants were individually randomized to receive 1 egg/day for 6mo (n=331) or continue their usual diet (n=329). In this secondary analysis, hemoglobin, plasma ferritin, sTfR, c-reactive protein (CRP), and a-1-acid glycoprotein (AGP) were measured at enrollment and 6mo follow-up. Iron biomarkers were corrected for inflammation. Ferritin, sTfR, BII, and hemoglobin concentrations were compared between groups using linear regression. Prevalence ratios (PR) for anemia (hemoglobin<11g/dL) and ID (ferritin<12µg/L, sTfR>8.3mg/L, or BII<0mg/kg) between groups were compared using log binomial or modified Poisson regression. Results: A total of 585 children were included in this analysis (Egg: n=286; Control: n=299). At enrollment, the total prevalence of anemia was 61% and did not differ between groups. At 6mo follow-up, groups did not differ in mean hemoglobin concentration [mean (95%CI); Egg: 11.0g/dL (10.8, 11.1); Control: 11.1 (11.0, 11.3)] and inflammation-adjusted ferritin [geometric mean (95% CI); Egg: 6.52µg/L (5.98, 7.10); Control: 6.82 (6.27, 7.42)], sTfR [Egg: 11.34mg/L (10.92, 11.78); Control: 11.46 (11.04, 11.89)] or BII [Egg: 0.07mg/kg (0.06, 0.09); Control: 0.07 (0.05, 0.08)]. There were also no group differences in prevalence of anemia [Egg: 43%; Control 40%; PR: 1.15 (95% CI: 0.96, 1.38)], ID [PR: 0.99 (0.94, 1.05)], or IDA [PR: 1.12 (0.92, 1.36)]. Conclusions: Providing eggs daily for 6mo did not affect iron status or anemia prevalence in this context. Other interventions are needed to address the high prevalence of ID and anemia among young, Malawian children.