(P11-051-25) Study Protocol: Isolating the Lactose-free Effect of A1 and A2 Beta Caseins on Digestive Discomfort, Gut Inflammation, and Gut Microbiome

Objectives: Digestive discomfort from dairy is often linked to lactose intolerance, but many individuals with dairy intolerance may not be lactose maldigesters. Beta-casomorphin-7 (BCM-7), an inflammatory metabolite of A1 beta-casein (β-CN) may play a role in dairy intolerance. Recent research highlights A2 β-CN milk as a beneficial alternative. We hypothesize that lactose-free A2/A2 milk would cause less digestive discomfort, gut inflammation, and dysbiosis in individuals with perceived dairy intolerance than A1/A2 milk.

Methods: A double-blind, randomized, controlled, cross-over study design will be employed. We will recruit 40 individuals with perceived dairy intolerance. Eligible and consented participants will enter 14 days of pre-intervention wash out period (D-13 to D0) with no dairy consumption. Individuals will then be randomly allocated to either A1/A2 or A2/A2 milk (for Phase 1 intervention of 14 days D1 to D15). A 14-day dairy washout period (D16 to D30) will follow Phase 1. Participants will then cross over to receive the opposite intervention (Phase 2, D31 to D45). On D-13, D15, and D45 participants will undergo a lactose challenge. Breath samples, symptom scores, blood and fecal samples will be collected. Blood will be analyzed for bovine BCM-7, IL-4/6, circulating glutathione/oxidized glutathione, myeloperoxidase, S-adenosylmethionine/ S-adenosyl homocysteine. Feces will be analyzed for calprotectin, short chain fatty acids, and microbiome (16s rRNA sequencing). The study is approved by the Institutional Review Board of Purdue University (IRB-2024-1469).

The Wilcoxon signed-rank test (symptom scores), Paired t-test (compare mean differences of parameters between 2 treatments), and two-way repeated measures ANOVA (calculate treatment effects, period effects, and potential carryover effects) will be used. Sequence data will be analyzed for alpha diversity and beta diversity.

Results: N/A

Conclusions: We expect that A2/A2 milk will lead to reduction in symptoms, gut inflammation and dysbiosis, and, if proven effective, it could serve as a nutritional option for individuals with dairy intolerant.

Funding Sources: Gift funds from A2 milk company