SREBF1 and vitamin B12 deficiency: Mechanistically, vitamin B12 deficiency directly affects the methionine cycle-SBP-1/sterol regulatory element-binding protein-1 (SREBP1)-adipogenesis axis, resulting in the accumulation of polyunsaturated fatty acids and heightened peroxidation levels, which was significantly suppressed by the addition of B12 supplementation (Figures 3B,C).