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Back in the 50s, it was suggested that some cases of constipation among children might be due to the consumption of cow’s milk, but it wasn’t put to the test until 40 years later. We used to think most chronic constipation in infants and young children was all in their head, they were anal retentive, or had some intestinal disorder, but these researchers studied 27 consecutive infants who showed up in their pediatric gastroenterology clinic with chronic idiopathic constipation, meaning they had no idea what was causing it, and tried removing cow milk protein from their diet.

Within three days, 21 out of the 27 children were cured. Symptoms completely regressed when a cow’s milk protein-free diet was used, and there was a clinical relapse during two subsequent cow milk challenges, meaning they then tried to give them back some cow’s milk and the constipation reappeared within 24 to 48 hours. And they did that twice. Same result. They stuck with the milk-free diet, came back a month later, and they stayed cured—and their eczema and wheezing went away too! The researchers concluded that many cases of chronic constipation in young children—more than three quarters it seemed—may be due to an underlying cow’s milk protein allergy.

Chronic constipation is a common problem in children, for which fiber and laxatives are prescribed. If that doesn’t work several laxatives at progressively higher dosages can be used, and that still may not work. Five years later a considerable number of kids are still suffering. In fact it may even extend into adulthood. So to cure the disease in just a few days by eliminating cow’s milk was a real breakthrough.

But this was an open study, meaning not blinded, not placebo-controlled, until … this landmark study was published in the New England Journal of Medicine, a double-blind, crossover study, cow’s milk versus soy milk. Sixty-five kids suffering from chronic constipation, all previously treated with laxatives without success; 49 had anal fissures and inflammation and swelling. An anal fissure is where there’s a rip or tear in the anus, very painful. They gave them either cow’s milk or soy milk for two weeks and then switched it around. So what happened?

In two thirds of the children, constipation resolved while they were receiving soy milk. And the anal fissures and pain were cured, whereas none of the children receiving cow’s milk had a positive response. In the 44 responders, the relation with cow’s milk protein hypersensitivity was confirmed in all cases by a double-blind challenge with cow’s milk. All those lesions, including the most severe anal fissures, disappeared on a cow’s milk-free diet yet reappeared within days after the reintroduction of cow’s milk back into their diet.

This may explain why children drinking more than a cup of milk a day may have eight times the odds of developing an anal fissure. Cutting out cow’s milk may help cure anal fissures in adults too, but then give them a cow’s milk challenge and their pain goes from 0 back up to 8 or 9 on a scale of 1 to 10. Cow’s milk may also be a major contributor to recurrent diaper rash.

Why though? All the studies looking at biopsy tissue samples in patients with chronic constipation because of cow’s milk protein hypersensitivity have signs of rectal inflammation. Bottom line, for all children with constipation who do not respond to treatment, a trial of the elimination of cow’s milk should be considered.

Regardless, studies from around the world have subsequently confirmed these findings, curing up to 80% of kids’ constipation by switching to soy milk or rice milk. A common problem with the studies though is when they switched kids from cow’s milk to nondairy milk, the kids could still have been eating other dairy products—they didn’t control the background diet, until now. A 2013 study got constipated kids off all dairy and 100% were cured, compared with the 68% in the New England Journal study where the background diet was unrestricted. In fact in that original study 20 years ago, the cow’s milk was replaced with soy milk or ass milk. Either was better than cow milk, but no mammary milk at all may be best.

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