Lao Zinc Study

Randomized, masked, community-based trial in rural Lao PDR to determine the effects of two forms of daily preventive zinc supplementation versus therapeutic zinc supplementation for diarrhea on young children’s physical growth and risk of new episodes of diarrhea

Zinc is an essential nutrient that is required for children’s normal growth and resistance to common infections. Current strategies for improving the growth and infection-related complications of zinc deficiency include: daily or weekly preventive zinc supplementation, and therapeutic zinc supplementation for 10-14 days in relation to episodes of diarrhea. The latter is recommended by the World Health Organization and UNICEF in conjunction with low-osmolarity oral rehydration salts (ORS) for diarrhea treatment. Information is needed on the relative impact of these intervention strategies on children’s growth, total morbidity burden from current and future infections and development.

The Lao Zinc study is a community-based, double-blind, randomized controlled trial to determine the optimal method for delivering zinc to young children, both for the prevention of zinc deficiency and treatment of diarrhea. The benefits and risks of a zinc-containing micronutrient powder (MNP) formulation including a higher amount of zinc dose (10 mg/d) and a low iron dose (6 mg/d) than current formulations will be compared with daily preventive zinc supplementation (7 mg/d) and therapeutic zinc interventions (20 mg for 10 days), using dispersible tablets.

A total of ~3,400 children 6-23 months of age will be enrolled in rural communities of the Khammouane Province in Central Lao PDR. Eligible children will be randomly assigned to one of the following 4 intervention groups and receive the respective intervention package for 36 weeks: 1) micronutrient powder plus ORS and placebo tablets for diarrhea; 2) placebo powder plus ORS and placebo tablets for diarrhea; 3) preventive zinc supplements provided as dispersible zinc tablets plus ORS and placebo tablets for diarrhea; and 4) therapeutic dispersible zinc tablets for diarrhea plus ORS and placebo preventive supplements provided as dispersible tablets. Children’s anthropometric indices will be assessed at baseline and after 18 and 36 weeks. Children will be visited weekly for morbidity surveillance. Micronutrient status, hemoglobinopathy, intestinal parasite burden, neuro-behavioral development and indicators of immune function, environmental enteric dysfunction and chronic stress will be assessed.

PICN research team


Funding agency

Different aspects of the Lao Zinc Study are supported by:


  • Khammouane Province, Lao PDR identifier

  • NCT02428647