Liquid Cow's Milk Consumption and Linear Growth Outcomes in Infancy and Childhood: A Systematic Review

Background: Linear growth during childhood is a key indicator of health status and child development, and liquid cow's milk has been proposed as a potentially relevant dietary component for this outcome. In this systematic review, we aimed to synthesize the available evidence on the association between liquid cow's milk consumption and linear growth outcomes in infants and children aged 6 months to 12 years. Methods: A systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines. Observational and experimental studies published in peer-reviewed journals, with no language restrictions, were included if they assessed habitual liquid cow's milk consumption as the main exposure and reported linear growth outcomes such as height, growth velocity, or height-for-age z-scores. Searches were performed in PubMed (MEDLINE) and Scopus from database inception to 15 January 2026. Study selection, data extraction, and risk-of-bias assessment were carried out systematically. Due to methodological heterogeneity among the included studies, results were synthesized narratively. Results: Twelve studies conducted across diverse geographic and socioeconomic contexts were included. Most studies reported positive associations between liquid cow's milk consumption and indicators of linear growth, including greater height, higher growth velocity, or improved height-for-age z-scores. Experimental studies showed significant increases in linear growth among children who received milk regularly, whereas some observational studies reported non-significant associations or results dependent on statistical adjustment. One study assessing complete cow's milk exclusion observed deceleration in linear growth. Overall, the risk of bias was predominantly moderate. Conclusions: Habitual consumption of liquid cow's milk during childhood appears to be predominantly associated with favorable linear growth outcomes, although variability exists according to study design, age at exposure, milk type, and exposure assessment. Further research using more robust designs is warranted to clarify the magnitude of the association, potential mechanisms, and implications for weight-related outcomes.