Study Links Age and Body Composition to Gut Bacteria Differences Among Milk Drinkers - Video

Differences in gut bacteria between consumers of cow's milk and plant-based beverages may reflect individual characteristics rather than beverage choices alone, according to a study published in Nutrients.

Researchers examined 265 adults to investigate whether habitual consumption of cow's milk, plant-based beverages or neither was associated with differences in gut microbiota composition.

Participants were classified into three groups: 139 cow's milk consumers, 27 plant-based beverage consumers and 99 non-milk consumers. Researchers analysed stool samples using bacterial DNA sequencing to assess microbial diversity and composition.

The gut microbiota plays important roles in immune regulation, intestinal barrier function, nutrient metabolism and the production of biologically active compounds. Dietary habits are among several factors that influence its composition.

Initial findings revealed small differences in gut microbial composition between cow's milk and plant-based beverage consumers. However, researchers found no significant differences in alpha diversity, which measures microbial diversity within an individual sample.

The researchers also observed differences in certain participant characteristics. Plant-based beverage consumers were younger and had lower body mass index and body fat percentages than participants in other groups.

To investigate whether these characteristics influenced the results, researchers used propensity score matching, accounting for factors including age, sex, body mass index, waist-to-hip ratio and body composition.

Following this adjustment, the previously observed differences in microbial diversity and individual bacterial taxa were no longer statistically significant.

These findings suggest that individual characteristics may partly explain apparent associations between milk choices and gut microbiota composition.

However, the study does not establish that cow's milk and plant-based beverages have identical effects on gut health

Further research involving larger populations, detailed dietary assessments and nutritional comparisons of individual products is needed to determine whether specific milk alternatives influence gut bacteria.

REFERENCE: La Placa, G., Gualtieri, P., Peluso, D., et al. (2026). Milk Consumption Patterns and Gut Microbiota Composition in Healthy Adults: Insights from a Propensity Score-Matched Cross-Sectional Study. Nutrients 18(19); 3272. DOI: 10.3390/nu18193272