INS and obesity due to melanocortin 4 receptor deficiency: It was also found that Bifidobacterium was a beneficial probiotic for health (Shu et al., 2023) as it reduces insulin resistance, blood lipids, and obesity in HFD-induced obese mice (Safari and Gérard, 2019; Wang Y. et al., 2020; Liu D. et al., 2023) while balancing gut-derived 5-HT (Pirozzi et al., 2023) and negatively correlating with TC and low-density lipoprotein cholesterol (Zhang et al., 2021).