Determinants of cow's milk and plant-based milk substitute consumption: cross-cultural study of Portuguese and Irish young adults

Introduction: Among European countries, consumption of milk has recently declined, while plant-based milk substitutes (PMBSs) have gained popularity, especially among young adults. Understanding the dynamics underlying these changes is particularly relevant to the agri-food sector. This study aimed to explore the determinants of cow's milk and PBMS consumption among Portuguese and Irish young adults.

Methods: A self-administered online questionnaire was distributed to young adults (18-35 years) recruited through the academic communities of the University of Porto and University College Cork. The reasons for consuming or not consuming cow’s milk and PBMSs were assessed using 10-item seven-point Likert scales. Exploratory factor analysis was used to identify factors within each scale, and multigroup confirmatory factor analysis was used to confirm measurement invariance across countries. Binary logistic regression was performed to quantify the relationship between sociodemographic characteristics, diet-related attitudes and behaviours, and the consumption of cow’s milk and PBMSs.

Results: A total of 645 participants was obtained, of which 57.2% consumed cow’s milk, mostly UHT milk (among Portuguese) and fresh milk (among Irish) and 54.4% consumed PBMSs (mainly almond and soy). The most important reason for consuming cow’s milk was complementarity (among Irish) and familiarity and taste (among Portuguese); for PBMSs, in both countries, it was health and sustainability. The most important reason for not consuming cow’s milk was health/environmental concerns, while for PBMSs it was taste. Gender, level of trust in different sources of diet-related information, dietary patterns, and food restrictions showed significant associations with cow’s milk and PBMS consumption, although differently among Portuguese and Irish individuals.

Conclusions: These results highlight the importance of targeting specific product characteristics, namely through the optimisation of production and development processes, to approach young consumers’ expectations. Educational strategies on the advantages and disadvantages of each product would also be important to enable informed food choices.