(P42-42-26) Postprandial Glucose and Metabolomic Responses to Milk β-Casein Variant and Pasteurization Method (HTST vs UHT): Protocol for a Randomized 4-Period Crossover Trial

Objectives: This protocol describes a randomized 4-period crossover trial designed to evaluate whether milk β-casein variant and pasteurization intensity influence postprandial glucose, insulin, and circulating metabolite responses in healthy adults.

Methods: This study is a randomized 4-period crossover clinical trial. Thirty healthy adults (≥18 y, without diabetes) will complete four test visits following an overnight fast (≥8 h). At each visit, participants will consume one of four test beverages in random order: (1) standard pasteurized 2% A1/A2 β-casein milk, (2) ultra-pasteurized 2% A1/A2 β-casein milk, (3) ultra-pasteurized 2% A2-only milk, or (4) a standardized 75 g oral glucose beverage control . Blood samples will be collected through an indwelling intravenous catheter at baseline and every 15 minutes for 120 minutes to measure plasma glucose and insulin. Incremental area under the curve (iAUC) for glucose and insulin will serve as the primary outcomes. Additional plasma samples collected at 0, 30, 60, and 120 minutes will undergo targeted metabolomic profiling to quantify amino acids, acylcarnitines, and energy metabolism intermediates associated with postprandial substrate utilization. Secondary outcomes will include treatment-related differences in circulating metabolite profiles and their associations with postprandial glycemic responses. Outcomes will be compared across treatments using repeated-measures mixed-effects models.

Results: N/A

Conclusions: This protocol will evaluate whether milk β-casein composition and pasteurization intensity influence postprandial glucose metabolism following dairy consumption. Findings will provide mechanistic insight into how dairy protein variants and processing affect postprandial glycemic responses and insight relevant to dietary recommendations for individuals at metabolic risk.

Funding Sources: Research support provided by The a2 Milk Company.