The Effects of Cow’s Milk on Babies

Evolution devised an ingenious way to bond infant to mother: proteins in milk that break down into peptides that have opiate-like drug effects. But what if a breastfeeding mother is herself effectively suckling by still drinking milk into adulthood? Evolution never counted on that, which may explain a recent case report entitled “Cow’s Milk-Induced Infant Apnea With Increased Serum Content Of Bovine Beta Casomorphin 5″ published in the Journal of Pediatric Gastroenterology and Nutrition.

Casomorphin is one of the opioid compounds formed in our stomachs when we drink milk. Infant apnea refers to when a baby stops breathing. The researchers “report a case of a breast-fed infant with recurrent apnea episodes, which have always been preceded by his mother’s consumption of fresh cow’s milk.” Lab tests revealed a high level of casomorphin in the child’s blood, leading researchers to speculate that it was the “opioid activity that may have a depressive effect on the respiratory center in the central nervous system and induce a phenomenon called milk apnea.”

“The aim of the present report,” the paper concludes, “is to draw researchers’ attention to the possibility of occurrence of a systemic reaction with an apnea seizure on the infant’s exposure to the proteins in cow’s milk. We are convinced that such a clinical situation occurs rarely; however, it is accompanied by a real threat to the infant’s life that can be avoided when applying a simple and not costly dietetic intervention” (a dairy-free diet). You can see more about the report in my 3-minute video Cow’s Milk-Induced Infant Apnea.

The reason this is so concerning is that as many as 1 in 10 infants with recurrent apneic episodes cannot be saved and tragically die of SIDS, sudden infant death syndrome (also known as crib death). SIDS is the leading cause of death for healthy infants after one month of age. One in every 2,000 American babies dies this way. Every day six babies stop crying and six parents start.

The suggestion that the opiate-like effects of a protein in cow’s milk could cause an infant to stop breathing was so provocative that researchers have started testing other high-risk kids. In my 2-minute video, Cow’s Milk Casomorphin and Crib Death, I detail a study in which the blood levels of the morphine-like peptides from cow’s milk averaged three times higher in infants with acute life-threatening episodes than those in healthy infants. It turns out there is an enzyme that gets rid of casomorphins, but the activity of that enzyme in the affected group was only half that of the healthy kids. Thus, some babies may just not be able to clear it out of their systems fast enough and are placed at risk for SIDS. The researchers conclude: “Penetration of beta-casomorphins into the infant’s immature central nervous system may inhibit the respiratory center in the brainstem leading to abnormal ventilatory responses, hypercapnia [too much carbon dioxide], hypoxia [not enough oxygen], apnea, and death.”

The opiate-like casomorphins liberated from the cow’s milk protein, casein, are also accused of participating in the cause of other conditions including type I diabetes, postpartum psychosis, circulatory disorders, food allergies, and autism–the subject of my video pick today (see above).

Breast is always best, but the breast milk of women eating plant-based diets may be better still. This would not only reduce or eliminate exposure to bovine casomorphins, but also lower levels of industrial pollutants such as dioxins. See, for example, my 4-minute video Flame Retardant Chemical Contamination. For other effects animal products may have on healthy development see Dairy & Sexual Precocity and Protein and Puberty. No wonder Dr. Spock—the most esteemed pediatrician of all time—ended up recommending children be raised without exposure to meat and dairy.

In health,
Michael Greger, M.D.

Image credit: Moff / Flickr

Breast Cancer Survival and Soy
Improving Mood Through Diet
Harvard’s Meat and Mortality Studies


William C
William Cabout a year ago


W. C
W. Cabout a year ago

Thank you.

Kathy Perez
Kathy Johnson5 years ago

I hear a lot of conflicting data about milk and dairy. What I know, however, is that my great grandmother lived into her 90s drinking cows milk every day of her life, my grandmother is 72 and drinks about half a gallon a day. My bfs grandparent go through a gallon every 3 days.. we consume about a gallon every other day. They are in their mid 80s and very healthy. We are healthy so far. It can't be as bad as some people think.. especially if you can obtain it locally

Lika S.
Lika P5 years ago

Back in the day, this did not happen. I have a 97 year old home care client that couldn't breast feed because her nipples are inverted. The wide spread of baby formula wasn't around back then, so she gave her babies cow's milk, and they both are in their 60's now, with no disabilities.

Terry Vanderbush
Terry V5 years ago


rita b.
Rita B5 years ago

If you want some really well researched in depth information on dairy products go to

I eat very little dairy once in awhile for a treat a tiny amount of raw goat or sheep cheese or organic butter on holidays.

Most adults are lactose intolerant and dairy also contributes to congestion since the major protein in cow's milk is casein - otherwise known as glue!

Julianna D.
Juliana D5 years ago

PASTUERIZED MILK does these things... not RAW milk.

James S.
james S5 years ago

Carol P. - is the goat's milk or cow's milk necessary? Are there nutrients in there that can't be obtained without taking what is meant for another? Vegan agenda? What agenda would that be? The one that seeks to end/limit the horrific ways we use animals? I'm sure you'll mention that you hate factory farming (that's very noble) and there are small farms...; however, the only way that factory farms will go away is if demand goes way down. That's the only way, besides inevitable destruction that becomes so bad that people can no longer look away without changing. Advocating for the milk of others is advocating for factory farming - that may not be your intention, but that's what's going on - someone may read your words and actually believe that they need goat's milk or cow's milk and that probably wouldn't be the case since the overwhelming majority of humans can thrive by eating plant based foods only.

Heidi Aubrey
Heidi Aubrey5 years ago

I was bottle fed and loved my mother very, very much as a tot, as I still do.

Jennifer Walsh
Jennifer Walsh5 years ago

thanks for the article!