Zinc can help prevent diarrhea

Infants and children who suffer from frequent episodes of diarrhea, lose a lot of  zinc in their diets before it can be absorbed. Not having adequate amounts of zinc in the body can delay a child's growth and sexual development of children. Zinc is also important in protecting our immune system, building DNA, and metabolizing other nutrients.

The effect of zinc was shown in India, where infants (6-11 months of age) with frequent diarrhea were given a 20 mg of zinc for 2 weeks. Five months later , the episodes of diarrhea dropped 39% and each episode was shorter when compared to infants who did not receive the supplement. (A Malik and others.  Pediatrics. 2013;pages 2012-2980). 
Zinc supplements may be important in the United States and Europe for those infants who have frequent diarrhea and infections, since zinc can be lost. Zinc  may also be low in some diets that do not contain fish or meat (which are good sources of zinc).