Arsenic Exposure Decreases Adiposity During High‐Fat Feeding

Objective Arsenic is an endocrine‐disrupting chemical associated with diabetes risk. Increased adiposity is a significant risk factor for diabetes and its comorbidities. Here, the impact of chronic arsenic exposure on adiposity and metabolic health was assessed in mice. Methods Male C57BL/6J mice were provided ad libitum access to a normal or high‐fat diet and water +/− 50 mg/L of sodium arsenite. Changes in body weight, body composition, insulin sensitivity, energy expenditure, and locomotor activity were measured. Measures of adiposity were compared with accumulated arsenic in the liver. Results Despite uniform arsenic exposure, internal arsenic levels varied significantly among arsenic‐exposed mice. Hepatic arsenic levels in exposed mice negatively correlated with overall weight gain, individual adipose depot masses, and hepatic triglyceride accumulation. No effects were observed in mice on a normal diet. For mice on a high‐fat diet, arsenic exposure reduced fasting insulin levels, homeostatic model assessment of insulin resistance and β‐cell function, and systemic insulin resistance. Arsenic exposure did not alter energy expenditure or activity. Conclusions Collectively, these data indicate that arsenic is antiobesogenic and that concentration at the source poorly predicts arsenic accumulation and phenotypic outcomes. In future studies, investigators should consider internal accumulation of arsenic rather than source concentration when assessing the outcomes of arsenic exposure.