Daily preventive zinc supplementation increases the antibody response against pathogenic Escherichia coli in children with zinc insufficiency: A randomized controlled trial

Authors: KEWCHAROENWONG, CHIDCHAMAI - Chiang Mai University; SEIN, MYINT MYINT - Falcuty Of Science Khon Kaen University; NITHICHANON, AMONE - Falcuty Of Science Khon Kaen University; KHONGMEE, A - Falcuty Of Science Khon Kaen University; WESSELS, R - University Of California, Davis; HINNOUHO, GUY-MARINO - University Of California, Davis; BARFFOUR, MAXWELL - University Of California, Davis; KOUNNAVONG, SENGCHANH - Tropical Medicine Research Institute; HESS, SONJA - University Of California, Davis; Stephensen, Charles; LETMEMONGKOLCHAI, GANJANA - Falcuty Of Science Khon Kaen University

Submitted to: Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/13/2022
Publication Date: 9/27/2022
Citation: Kewcharoenwong, C., Sein, M., Nithichanon, A., Khongmee, A., Wessels, R.K., Hinnouho, G., Barffour, M.A., Kounnavong, S., Hess, S.Y., Stephensen, C.B., Letmemongkolchai, G. 2022. Daily preventive zinc supplementation increases the antibody response against pathogenic Escherichia coli in children with zinc insufficiency: A randomized controlled trial. Scientific Reports. 12. Article 16084. https://doi.org/10.1038/s41598-022-20445-8.
DOI: https://doi.org/10.1038/s41598-022-20445-8

Interpretive Summary: Zinc deficiency impairs immune function, including the antibody response to infection. Zinc deficiency is common among young children from lower-income countries, including Laos, where this study was done. In this study, the effect of zinc supplementation on changes in E. coli-specific antibody levels between study baseline and endline of Laotian children was determined as a secondary analysis from a randomized controlled trial of zinc supplementation. The goal was to determine if zinc supplementation increased the antibody levels or antibody avidity (i.e., strength of binding to the E. coli antigen). Plasma samples from study baseline and endline were analyzed from a sub-group of 200 study participants aged 6–23 m who received one of four treatments during the study period: daily placebo powder (control), therapeutic dispersible zinc tablets in response to episodes of diarrhea (TZ), daily multiple micronutrient powder (MNP), or daily preventive zinc tablets (PZ). Samples were analyzed for immunoglobulin G (IgG) concentration specific for pathogenic E. coli, and IgG avidity index. More than 78% of children in this study group were zinc deficient based on plasma zinc concentration. Study participants in the TZ group showed the highest percentage of increased IgG level while PZ group showed reduced percentage of children with decreased IgG level and avidity index. Interestingly, only the PZ group significantly increased both IgG level and % avidity index of children who were zinc deficient. This finding suggests that the daily preventive zinc tablets might be a useful regimen for zinc supplementation based on the increased antibody response.

Technical Abstract: Zinc deficiency impairs the antibody-mediated immune response and is common in children from lower-income countries. In this study, the effect of zinc supplementation on antibody response of Laotian children was determined in a secondary analysis from a randomized controlled trial. Leftover plasma samples of baseline and endline from a sub-group (n = 200) aged 6–23 mo who received daily placebo powder (control), therapeutic dispersible zinc tablets (TZ), daily multiple micronutrient powder (MNP), and daily preventive zinc tablets (PZ) were randomly selected and measured for immunoglobulin G (IgG) level and % avidity index to pathogenic E. coli. Plasma zinc and complete blood count (CBC) were also determined. More than 78% of children in this study group were zinc deficient and 40.0% shown abnormally low hemoglobin. In addition, TZ group showed the highest percentage of increased IgG level while PZ group showed reduced percentage of children with decreased IgG level and % avidity index. Interestingly, only PZ group significantly increased both IgG level and % avidity index of children who were zinc deficient. This present study suggested that PZ might be the optimal regiment for zinc supplementation based on the increased antibody response.