The LaoBiome Study is a community-based, randomized, placebo-controlled trial with two study arms conducted in Lao People's Democratic Republic. This study aims at providing evidence on impact of For-baby powder supplement on child physical growth, diarrheal incidence, environmental enteric dysfunction, adherence to the intervention, and neuro-behavioural development of: 1) daily administration of For-Baby powder supplements (Intervention Group) and 2) daily administration of micronutrient powder (Placebo-Controlled Group).

Probiotics are delivered as multiple micronutrient supplements in a powder package (For-Baby powder's sachet) and add into a single serving of clean water or breast milk and spoon feed the powder to the child 30 minutes before or after food consumption or add to semi-solid or mashed food such as mashed mango, banana and papaya, boiled pumpkin, and boiled egg after the food has been cooked and cooled sufficiently to be eaten (but within 30 minutes of preparation). Recent studies has shown that certain probiotics are extremely useful for the treatment of environmental enteropathy in malnourished children and has significant growth promoting effects. Nonetheless, new studies are needed to better understand the environmental enteropathy and its consequences.

This community-based, randomized, placebo-controlled trial with two groups will be conducted in the community of Luangprabang province in the northern part of Lao PDR.

The study team will enroll a total of 1,200 children, aged 6-23 months into the trial. The children will be randomly assigned one of two groups: 1) intervention group of daily For-Baby powder supplements and 2) control group of daily micronutrient powder supplements. After enrollment, the children will be under the observation for a total of 12 months (52 weeks). The monitored outcomes are the physical growth, diarrheal episodes, motor and intellectual development, gut microbiota and intestinal parasitic infections.

Inclusion Criteria:

• Children 6-23 months of age at enrollment,
• Acceptance of weekly home visits for growth surveillance,
• Planned residency within the study area for the duration of the study period (52 weeks),
• Signed informed consent from a parent or legal caregiver.

Exclusion Criteria:

• Weight-for-height z-score (WHZ) <-3SD with respect to World Health Organization 2006 standards;
• Presence of bipedal edema;
• Severe illness warranting hospital referral;
• Congenital abnormalities potentially interfering with growth;
• Chronic medical condition (e.g., malignancy) requiring frequent medical attention;
• Known human immunodeficiency virus (HIV) infection of index child or child's mother;
• Severe anemia (hemoglobin <70 g/L; based on testing at enrollment);
• Currently consuming MNP supplements;
• Current participation in any other clinical trial.

Criteria for discontinuation:

A subject can be discontinued from the study for the following reasons:

• Withdraws from the study (this can happen anytime as participation is voluntary and there are no further obligations).
• At the discretion of the principal investigator, if the participant is not compliant to the requirements of the protocol.
• Discontinued subjects will not be replaced. If, for any reason, a subject is discontinued from the study before the end of the evaluations, the safety procedures planned (AEs monitoring) will be conducted. Data obtained prior to subject's withdrawal will be included in analysis. Data of withdrawn patients are fully anonymized once analysis is completed.

The randomization scheme will be generated by an independent Statistician using a computer-generated block randomization scheme, with randomly selected block lengths of 4. Each of the two study arms will be identified by a unique 1-digit code (1, 2). The Institut Pasteur du Laos (IPL) member, unaffiliated with the study, will be responsible for assigning each of the two study codes to an intervention product and communicating this information directly to the product manufacturers. The identity of the treatment codes is stored in sealed envelopes held by the co-principal investigators (PIs) and the statistician. The envelopes will be opened only after statistical analyses of primary outcomes are completed and consensus on the interpretation of results is reached, unless required by one of the IRBs or the Project Steering Committee.