Background: Zinc deficiency is associated with alteration in gastrointestinal tract structure, function, and impaired immune function.

Aim: To analyze the effects of zinc deficiency on the occurrence of acute diarrhea in exclusively breast-fed infants.

Methods: In a case-control study, including a total of 72 exclusively breast-fed infants aged ≤ 6 months, 34 of them with acute diarrhea were in the study group and 38 infants as the healthy control group. Demographic characteristics of all infants and their parents were studied. Serum Zinc level was measured for all participants.

Results: Zinc level had significant (p-value =0.000) differences between infants with acute diarrhea and the healthy control group. The mean serum zinc value ± SEM in children with acute diarrhea was 63.11 ± 1.7 which was significantly (p = 0.000) different from the mean serum zinc value ± SEM (78.6 ± 1.6) in healthy infants. A cut-off value 60.6μg/dl of total serum zinc level was significantly (p = 0.000) associated with a sensitivity of 100 % with the occurrence of acute diarrhea among exclusively breast-fed infants.

Conclusions: Low serum zinc level is associated with the occurrence of acute diarrhea in exclusively breast-fed infants. A cutoff serum zinc value of 60.6 μg/dl has 100% sensitivity with the occurrence of acute diarrhea among breast-fed infants.

Keywords: Zinc deficiency, diarrhea, infants, breastfeeding.