Supplementation of HF diets with 0.3%–1% guar gum decreased oxidative stress through Nrf2‐Keap1 pathway activation, enhanced mucosal barrier function by upregulating tight junction proteins, and reduced gut inflammation by inhibiting the TLR‐Myd88‐NF‐κB pathway. The gene discussed is NFKB1; the disease is hydrops fetalis.