 This report on cow's milk-induced infant apnea, thought due to the opiate-like effects of bovine casomorphin and milk, was just a single case report. It was so provocative, though researchers immediately started testing other kids. SIDS, Sudden Infant Death Syndrome, also known as CRIB death, is the leading cause of death for healthy infants after one month of age. One in every 2,000 American babies die this way. Every day, six babies stop crying, and six parents start. Most susceptible are infants exposed to several postnatal factors, sleeping on their stomachs, a secondhand smoke, high sleep room temperatures, but it is supposed that in some cases of SIDS, it is cow's milk that may play a certain role. It is also suspected that beta-casomorphins hold a direct responsibility for that situation. Beta-casomorphins are biologically active with, as its name suggests, effects similar to that of morphine. Penetration of beta-casomorphins into the infant's immature central nervous system may inhibit the respiratory center and the brainstem leading to abnormal ventilatory responses, hypercapnia, which means too much carbon dioxide, hypoxia, not enough oxygen, apnea, and death. So what they did was study infants who had recurrent life-threatening episodes, meaning apnea, where they stopped breathing, or turned blue, or become limp, etc. These are the kinds of events that place babies at high risk for SIDS. The blood levels of bovine casomorphin in the babies with the acute life-threatening events average three times higher than healthy babies. Why? Well, there's an enzyme that gets rid of casomorphin, and the activity of that enzyme in the affected group was only half that of the healthy kids. So some babies may just not be able to clear it out of their systems fast enough and are placed at risk for death.