Synergistic Effects of Short- and Long-Chain Fructans: A Novel Strategy for Mitigating Ovalbumin Allergy via Microbiome-Driven Acetate Production.

The gut microbiota has been implicated in the modulation of food allergies. Building on previous studies on the preventive effects of combining short-chain fructan 1-kestose (Kes) and long-chain fructan inulin (Inu) in food allergies, we investigated their therapeutic effects in an ovalbumin (OVA)-induced food allergy mouse model. Following OVA sensitization, the mice received 5% Kes and Inu, either individually or a combined 2.5% dose of each, for 4 wk. We assessed allergy-related markers, such as OVA-specific serum IgE (OVA-sIgE) levels, in the blood and monitored changes in the gut microbiome. The intake of fructans ameliorated allergic symptoms and stabilized rectal temperatures, with a significant reduction in OVA-sIgE levels only in the combined Kes and Inu group (Kes+Inu), p<0.05. Gut microbiota diversity analysis revealed significant differences in beta diversity between the groups not receiving fructans and those receiving Kes, Inu, or Kes+Inu (p<0.01 each). Specifically, in the Kes+Inu group, the abundance of the genus UBA7173 belonging to the family Muribaculaceae significantly increased. Additionally, acetate levels were significantly elevated only in the Kes+Inu group and correlated positively with the presence of the genus UBA7173. These findings indicated that the combined intake of Kes and Inu improves allergic outcomes, positively affects the gut microbiome, and enhances the production of acetate.