Overview
The purpose of this study was to identify and compare the effects of daily consumption of A2 milk, conventional milk, and an oat drink on bone health, cardiometabolic health, and immune system function in adults. Although cow's milk plays an important role in human nutrition, its proteins-particularly β-caseins-exhibit significant genetic diversity. Conventional milk typically contains a mix of A1 and A2 β-casein variants, whereas A2 milk contains exclusively the A2/A2 variant. The key difference between the two lies in a single amino acid at position 67: variant A1 contains histidine, which allows digestive enzymes to release the opioid peptide β-casomorphin-7 (BCM-7), while variant A2 contains proline, which prevents the release of this peptide. Consequently, the study is trying to answer the question of whether 12 weeks of consuming 500 ml of A2 milk daily-thereby eliminating dietary exposure to BCM-7-results in different outcomes for bone health (the primary measure), as well as for cardiometabolic health and immune function, when compared to consuming conventional milk or a plant-based oat drink in healthy adults aged 30-60.
Eligibility
Inclusion Criteria:
- aged 30 to 60 years,
- body mass index \>18.5 or \<30 kg/m2,
- no diagnosed chronic disease, i.e. diabetes, cancer, kidney disease,
- not taking medications/dietary supplements that may affect carbohydrate and/or lipid metabolism.
Exclusion Criteria:
- pregnancy or lactation in women,
- implanted medical materials such as: pacemaker, defibrillator, stent, metal suture in the heart or blood vessel, and implants,
- previous radiotherapy and/or chemotherapy,
- significantly modified diet (e.g., ketogenic, vegetarian, or ovo-vegetarian) and health condition requiring a specialist diet,
- unable to give informed consent,
- unable or unwilling to comply with the study procedures,
- have medical history of gastrointestinal surgery or disorders (inflammatory bowel disease, ulcerative colitis, coeliac disease, Crohn's disease), cardiorespiratory problems, uncontrolled diabetes mellitus, bleeding disorders.
Non-exclusion criteria:
- hypertension, or depression that are well-controlled with medical intervention.
