Effect of the Consumption of Milk with Beta-Casein A2A2, Milk with Beta-Casein A1A2 and a Plant-Based Drink on Metabolic Health in Adults: Protocol IMPA-CT Study.

Background and Objectives: Milk with A2/A2 β-casein (A2 milk) is currently the subject of numerous studies on the effects of its consumption on health. Commonly consumed milk contains a mixture of β-casein of different genetic variants (most often A1 and A2). In the polypeptide chain of A2/A2 β-casein, proline occurs at position 67, while in β-casein A1/A2, histidine occurs. The main goal of the dietary intervention was to identify and compare the effects of consuming A2 milk, conventional milk (A1) and oat drink on bone health, cardiometabolic health and immune system function in adults. Methods: The controlled IMPA-CT (Investigating Milk and Plant Alternatives Comparative Trial) Study was a randomized study with three groups (A2 Milk group, A1 Milk group, and Oat Drink group). The study included 162 adults with normal and/or overweight, without coexisting chronic diseases, aged 30-60 years. The intervention study consisted of the consumption of 500 mL of an appropriate product (A2 milk/A1 milk/oat drink) daily for 12 weeks. After qualification of the subjects, before the start of the study (T1'), in the 4th week of the study (T2'), in the 8th week of the study (T3') and at the end of the study, after 12 weeks (T4'), an assessment of the diet and nutritional status was planned. Body composition, bone mineral density (DEXA) and biochemical tests were done. The primary outcome will be the effect of cow's milk variants and oat drink consumption on bone health. Secondary outcomes will include changes in nutrient intake and cardiometabolic health as well as the immune system in adults. Expected Results and Contributions: The study design, including extensive follow-up and robust endpoint measures, contributed to understanding the therapeutic potential and safety profile or otherwise of β-casein A2/A2 milk and plant-based drinks.