Hypoglycemia and altered bile acid metabolism are linked to latent iron deficiency in young Japanese women

Iron deficiency anemia (IDA) remains a prevalent health issue, especially among Japanese women, and may be influenced by dietary patterns and lipid metabolism. This study aimed to investigate the association between circulating bile acid (BA) concentrations and iron-related biomarkers in young Japanese women. Blood biochemical and anthropometric data were collected from 33 healthy young women aged 20. The participants can be divided into two groups based on the levels of total-iron binding capacity (TIBC), although their hemoglobin and ferritin levels were in the normal ranges. When participants were divided based on TIBC, the low TIBC group showed significantly higher levels of 12-hydoxylated, non-12-hydoxylated, and total BAs, as well as significantly lower blood glucose levels compared to the normal group (p < 0.05). Positive correlations were observed between TIBC and specific BA species, such as glycolithocholic acid (ρ = 0.3993, p < 0.0288), cholic acid (ρ = 0.4767, p < 0.0077), and taurocholic acid (ρ = 0.4423, p < 0.0144). Additionally, transferrin levels were positively correlated with glycholithocholic acid (ρ = 0.3649, p < 0.0474). These findings suggest that TIBC may serve as an early indicator of hypoglycemia, reflecting preclinical metabolic disturbance, in addition to being a latent IDA marker.