Australian Immunity Trial (Trial A): The effect of milk proteins on immune function in healthy young adults

There is some evidence that A2 beta-casein versus A1/A2 beta-casein milk has beneficial effects on immunity, inflammation, gut health, and cognition function through multiple blinded RCTs (Trivedi 2017; Jianqin 2015; Ho 2014; Deth 2015). Another component of milk, lactoferrin, is thought to have immuno-modulating properties (Kell, 2020). When consumed orally, lactoferrin is mostly absorbed, with a small amount reaching the lower bowel (Yamuchi, 2006). In humans, orally consumed bovine lactoferrin has improved systemic and gut immunity (Sachdeva, 2009; Yamuchi, 2006). We hypothesise that consumption of A2 milk, in conjunction with lactoferrin, will reduce markers of inflammation in healthy individuals. This study will test the effect of A2-only beta-casein milk fortified with bovine lactoferrin, as compared to A1/A2 beta-casein containing milk without lactoferrin fortification in a double-blind, randomised controlled trial. Healthy young adults will be randomised to recieve either cow's milk containing only A2 beta-casein protein plus lactoferrin, or cow's milk containing both A1/A2 beta-casein without lactoferrin for 14 days. Participants will be asked to complete questionnaires, have a blood sample collected, and provide a faecal sample at the start and end of each intervention period. Participants will also be asked to follow a standardised diet for the entire study and will have their main meals provided, including during a run-in period (14 days), during each intervention period (2 x 14 days), and washout period between interventions (14 days).