Opioid peptides from milk as a possible cause of sudden infant death syndrome.

Milk from breast or baby formula is the exclusive source of nutrition for newborn infants. Short chain opioid peptides such as beta-casomorphins have been isolated from breast milk as well as baby formula. These biologically active peptides are absorbed from the gastrointestinal tract. In infants predisposed to respiratory apnea because of abnormal autonomic nervous system development and respiratory control mechanisms, opioid peptides derived from milk might be one of the etiological factors for sudden infant death syndrome and near miss sudden infant death syndrome.