INS and metabolic syndrome: Zhao et al. [54] provided indirect evidence that oral administration of L-arabinose, a naturally occurring plant pentose, can induce hydrogen gas production through gut fermentation and alleviate HFD-induced MS, including gain in body weight and fat, impaired insulin sensitivity, liver steatosis, dyslipidemia, and elevated inflammatory cytokines, indicating that increasing endogenous hydrogen gas release through modulating gut microbial composition by administration of prebiotic nutrients or hydrogen-producing probiotics might be a promising approach for the treatment of MS.