Fortification of α-Lactalbumin and β-Casein in Infant Formula Alleviate Dextran Sulfate Sodium-Induced Colitis in a Young Rat Model: Assessment of Gut Barrier, Inflammatory Response, and Metabolites.
Zhao J, Zhang L, et al. • Journal of agricultural and food chemistry • 2026
Fortification of infant formula with α-lactalbumin and β-casein significantly improved colonic morphology, reduced barrier dysfunction, modulated inflammatory cytokines, shifted gut microbiota composition, and altered arachidonic acid and glycerophospholipid metabolites in a DSS-induced colitis young rat model.
Key Findings
Results
Fortification of infant formula with α-lactalbumin and β-casein significantly improved colonic morphology and reduced serum markers of intestinal barrier dysfunction in DSS-induced colitis young rats.
The study used a dextran sulfate sodium (DSS)-induced colitis model in young rats to simulate intestinal inflammation
The infant formula tested had a whey:casein ratio of 60:40, fortified with α-lactalbumin (α-La) and β-casein (β-CN)
Colonic morphology improvements were documented alongside reductions in serum markers associated with gut barrier dysfunction
Results were statistically significant at P < 0.05
Results
α-Lactalbumin and β-casein fortification upregulated epithelial junction proteins, with particularly notable effects on occludin expression.
Occludin upregulation was statistically significant (P < 0.05)
Epithelial junction proteins are critical components of the intestinal barrier and their upregulation indicates improved gut barrier integrity
Occludin was specifically highlighted as showing especially notable improvement among the junction proteins measured
Results
Fortification with α-lactalbumin and β-casein significantly modulated both proinflammatory and anti-inflammatory cytokine levels in colitis-induced rats.
Both proinflammatory and anti-inflammatory cytokines were affected by the fortification
Modulation was observed specifically in the colitis-induced animals
Changes were statistically significant at P < 0.05
The dual modulation of both pro- and anti-inflammatory cytokines suggests a broad immunomodulatory effect
Results
α-Lactalbumin and β-casein fortification induced genus-level shifts in gut microbiota composition, increasing beneficial genera and decreasing potentially proinflammatory taxa.
Beneficial genera showing increased abundance included Akkermansia
Potentially proinflammatory taxa showing decreased abundance included Desulfovibrio
Changes were characterized at the genus level of microbial taxonomy
The microbiota shifts were described as associated with the fortification intervention rather than DSS alone
Results
Fortification with α-lactalbumin and β-casein modulated levels of several arachidonic acid and glycerophospholipid metabolites.
Metabolites from both arachidonic acid and glycerophospholipid pathways were affected
Specific metabolites identified included prostaglandin D2 (PGD2), 15-deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2), and 2-arachidonoylglycerol (2-AG)
These metabolites are known to have roles in inflammatory signaling pathways
Metabolomic profiling was used to identify these changes
Results
Correlation analysis revealed specific associations between lipid metabolites and gut microbiota genera, linking prostaglandins to beneficial bacteria and 2-arachidonoylglycerol to other microbial taxa.
Prostaglandin D2 (PGD2) and 15-deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2) were positively associated with Bifidobacterium and Blautia
2-Arachidonoylglycerol (2-AG) was positively correlated with Parabacteroides and Enterobacteriaceae
These correlations suggest a potential gut microbiota–metabolite axis influenced by the protein fortification
Both Bifidobacterium and Blautia are generally considered beneficial gut bacteria, while some Enterobacteriaceae members are associated with inflammation
What This Means
This research suggests that adding specific milk proteins — alpha-lactalbumin and beta-casein — to infant formula can help reduce intestinal inflammation and protect the gut lining. The researchers tested an infant formula fortified with these proteins in young rats that were given a chemical (dextran sulfate sodium) to induce colitis, which is a form of intestinal inflammation. Compared to unfortified formula, the fortified version improved the physical structure of the colon, strengthened the proteins that hold the gut lining together (especially a protein called occludin), and helped balance both inflammation-promoting and inflammation-reducing immune signals.
The fortified formula also appeared to beneficially shift the communities of bacteria living in the gut. Bacteria associated with gut health, like Akkermansia, became more abundant, while bacteria linked to inflammation, like Desulfovibrio, became less common. At the same time, the fortification changed the levels of certain fat-related molecules (metabolites) involved in inflammatory signaling, including prostaglandins. Interestingly, there were meaningful correlations between specific metabolites and specific bacterial groups, suggesting the proteins may work partly by influencing how gut bacteria and inflammatory molecules interact with each other.
This research suggests that the specific type and ratio of proteins in infant formula — not just the total protein content — may matter for supporting gut health in infants, particularly when the intestinal tract is stressed or inflamed. Since infant gut development is a critical period, these findings could be relevant to designing infant formulas that better mimic the protective components of human breast milk, though further research in humans would be needed to confirm these effects.
Zhao J, Zhang L, Wang X, Szeto I, Duan S, Yan Y, et al.. (2026). Fortification of α-Lactalbumin and β-Casein in Infant Formula Alleviate Dextran Sulfate Sodium-Induced Colitis in a Young Rat Model: Assessment of Gut Barrier, Inflammatory Response, and Metabolites.. Journal of agricultural and food chemistry. https://doi.org/10.1021/acs.jafc.5c16596