The ‘Whey’ to good health: Whey protein and its beneficial effect on metabolism, gut microbiota and mental health

Background: Whey protein (WP) and its components account for 20% of bovine milk proteins. Once considered as a waste by-product of cheese production, WP is now known to exert beneficial effects on human health, specifically with respect to controlling obesity and its comorbidities. Scope of review: This review provides an overview of the physical and chemical characteristics of all bovine milk proteins, i.e., WP, WP components. Next, the available evidence relating to the beneficial effects exerted by WP and its components with respect to satiety, energy balance, metabolism and inflammation have been reported and discussed. Importantly, the review includes a focus on the changes to the gut microbiota that can occur in response to WP consumption, while also highlighting the positive impact of WP on mood and behaviour. Finally, this review provides possible mechanisms through which WP supplementation confers beneficial effects during obesity and its comorbidities, taking into account the experimental factors/conditions that could impact on WP effects. Major conclusions: WP consumption positively impacts energy balance and obesity-related parameters. This has been primarily linked with modulation in adipose tissue metabolism and several changes that occur within the gastrointestinal tract, such as modulation of satiety hormones, nutrient transporters, intestinal permeability and possibly, gut microbiota changes. This review highlights critical points relating on the beneficial effects of WP supplementation in preventing or treating obesity and also notes areas of importance for further research on the topic.