Effects of probiotic yogurt on relative respiratory tract infections, urine, saliva biomarkers, and fecal bacterial load in Ugandan children: a randomized controlled trial

Abstract

This study evaluated the effects of locally produced probiotic yogurt on infectious diseases in Ugandan children aged 3-6 years. Over nine weeks, 196 children participated in a randomized, double-blind, placebo-controlled trial, consuming 125 ml daily of either probiotic yogurt containing Lacticaseibacillus rhamnosus yoba 2012 and Streptococcus thermophilus C106 or a non-fermented dairy placebo. The primary outcome, average daily incidence of upper respiratory tract symptoms, showed no significant difference between groups. However, the probiotic yogurt group experienced a significant reduction in respiratory tract infection symptoms over time (p = 0.02). Biomarker analysis revealed significant changes in the probiotic yogurt group, including higher urine hippurate levels (p = 0.02), increased lactic acid bacteria (p = 0.04) and total bacterial load (p = 0.04) in stool, and elevated SLPI (p = 0.005) in saliva from baseline to endline. Despite these within-group effects, the lack of significant differences between the yogurt and placebo groups highlights the need for further research with larger cohorts and longer durations to confirm the potential benefits of this probiotic yogurt for reducing infection symptoms and improving health biomarkers under these study conditions.