No, PETA, Cow Milk Does Not Cause Autism

The group that brought you animal-fur horror stories has just launched a campaign claiming cow’s milk causes autism. Hold on to your Cheerios, this one needs explaining.


PETA (People for the Ethical Treatment of Animals) earned its chops over the last few decades by raising public awareness about the cruelty of wearing animal fur. Using hard-hitting, obnoxious photos of fur-covered celebrities, they drove home their point—and changed the way many people think about wearing that mink in the process.

It is unsettling, therefore, to see them adopt the same take-no-prisoners approach to pushing an eccentric theory linking milk consumption to autism.

Their “Got Autism?” campaign features an aerial photo of a frowning string of Cheerios in a bowl of cereal. In the ad, they cite an article published by several Norwegian scientists in the journal Nutritional Neuroscience. The article, published in 2002 no less, was not the lead article in that particular volume. That honor went to “The Development of Food Preferences in Cats: The New Direction.”

The autism article described 20 children with well-characterized autism, 10 of whom went on a gluten- and casein (the protein in cow’s milk)-free diet and 10 of whom went about their business as usual. At the end of a year, the two groups were retested and the group on the restricted diet appeared to have improved, as evidenced by demonstrating fewer traits of autism, more than the kids on no particular diet. Other aspects of their autism, including language skills, were unchanged.

This study was one of many by the same research group that presents a thoughtful, not-nutty, biologically plausible way to link sensitivity to some ingested foods with a wide variety of symptoms. Lots of kids have food allergies; even more kids have parents who think they have food allergies. For example, I was an itchy kid and was placed for a few months on a diet without milk or chocolate; I continued to itch and flunked the test. I suspect I am not in the minority of children of worried parents to have been “experimented” on.

The topic of diet, specifically as it relates to gluten, casein, and autism, was the subject of a study released in the Journal of Child Neurology this April. After a thorough review, the authors recommended trying the dietary intervention only in children who exhibited other, more standard evidence of food sensitivity and allergy.

The drive to find the cause and cure of autism rivals the urgency and poignancy to find the cause and cure of cancer. And so, as with cancer, anything with a hint of possible truth is grabbed and trumpeted as the next big thing. Milk as a cause of or worsener of autism will have to join the long list of other putative causes. From refrigerator moms who apparently “chilled” their children into autism with a cold demeanor to the evil powers of shampoo and unfiltered water, many of the wildest theories were long ago abandoned. It’s vaccines, antibiotics, and the age of fathers that seem to rule the rhetoric today.

Given the vast uncertainty and the fiercely emotional context, it is difficult to dismiss any theory without proper study—and that’s what is exasperating about the PETA misstep. Not only are they putting early maybe-science out there as fact and giving unwarranted hope to countless parents, but they are interfering with the way science happens.

There probably is a small subset of children whose autism would improve—slightly—with changes in diet. But by sticking their nose into the issue, PETA has only served to marginalize serious researchers who might uncover useful information and place the topic into the hands of charlatans and faith healers, those who use family desperation as an opportunity to turn a buck.