Associations Between Intestinal Mucosal Function and Changes in Plasma Zinc Concentration Following Zinc Supplementation

Objectives:Subclinical environmental enteropathy is associated with malabsorption of fats, carbohydrates, and vitamins A, B-12, and folate; however, little information is available on mineral absorption. We therefore investigated the relation between intestinal mucosal function (measured by the lactulose:mannitol permeability test and plasma citrulline concentration), and zinc (Zn) absorption, as estimated by the change in plasma Zn concentration (PZC) following short-term Zn or placebo supplementation.Methods:We conducted a randomized, partially masked, placebo-controlled trial among 282 apparently healthy children 6 to 23 months of age in Burkina Faso. After completing baseline intestinal function tests, participants received either 5 mg Zn, as zinc sulfate, or placebo, daily for 21 days.Results:At baseline, meanstandard deviation PZC was 62.9 +/- 11.9 g/dL; median (interquartile range) urinary lactulose:mannitol (L:M) recovery ratio and plasma citrulline concentrations were 0.04 (0.03-0.07) and 11.4 (9.0-15.6) mol/L, respectively. Change in PZC was significantly greater in the Zn-supplemented versus placebo group (15.6 +/- 13.3 vs 0.02 +/- 10.9 g/dL; P<0.0001), and was negatively associated with initial urinary L:M recovery ratio (-1.1 g/dL per 50% increase in urinary L:M recovery ratio; P=0.014); this latter relation did not differ between supplementation groups (P=0.26). Baseline plasma citrulline concentration was not associated with change in PZC.Conclusions:Although altered intestinal permeability may reduce dietary Zn absorption, it likely does not undermine the efficacy of Zn supplementation, given the large increases in PZC following short-term Zn supplementation observed in this study, even among those with increased urinary L:M recovery ratios.