Autistic children display elevated urine levels of bovine casomorphin-7 immunoreactivity

•A novel high sensitivity ELISA method was developed.•Autistic children have a higher levels of bovine CM-7 in urine than normal.•The severity of autistic symptoms correlated with CM-7 immunoreactivity in the urine.•ELISA can be used for rapid dietary guidelines for autistic children.

Elevated concentrations of circulating casomorphins (CM), the exogenous opioid peptides from milk casein, may contribute to the pathogenesis of autism in children. Because several mass spectrometry studies failed to detect casomorphins in autistic children, it was questioned whether these peptides can be detected in body fluids by mass spec. Here we demonstrated, using a novel high sensitivity ELISA method, that autistic children have significantly higher levels of urine CM-7 than control children. The severity of autistic symptoms correlated with concentrations of CM-7 in the urine. Because CMs interact with opioid and serotonin receptors, the known modulators of synaptogenesis, we suggest that chronic exposure to elevated levels of bovine CMs may impair early child development, setting the stage for autistic disorders.