 There has been a long-standing problem among zookeepers of the gorilla, a lot named Gorilla Gorilla Gorilla. The problem is that they were throwing up all the time. We've never seen wild gorillas barfing, but it had unfortunately been accepted as routine by many zoos. What, were they feeding them? Well, you know, they're big, strong animals, so they made sure to feed them lots of protein. You know, cottage cheese, meat, eggs, milk. Until a zoo in Germany got this radical idea to try giving them their natural diet, and the change following the alterations to the diet was astonishing. I mean, before, the poor silverback was regurgitating and vomiting during most of the day, but by the third day eating what they were supposed to eat, he and the rest were all miraculously cured. And just removing milk from captive gorilla diets led to significant improvements. Cow's milk was historically considered an essential item in the captive gorilla diet, but they showed that removal of milk from the captive gorilla diet may reduce such undesirable behaviors and maybe a step towards better approximating their natural diet. I mean, giving an animal milk after weaning? Giving an adult animal milk? Milk is for babies. And then giving milk from a bovine to a primate? What were these crazy zookeepers thinking? Doesn't make any sense! Reminds me of this landmark study 81 children presenting with reflux, gastroesophageal reflux disease. So they were given drugs, and two-thirds got better, but 27 kids still did not. Now they tried eliminating cow's milk from their diets, and within one month all 27 were cured. Symptoms of acid regurgitation, heartburn, or both occur at least once a week, and 10 to 20% of adults in the Western world and about up to 25% of all infants. Now it's normal for babies to spit up occasionally. That's not what we're talking about. It can actually get quite serious. Up to a quarter of infants present with regurgitation severe enough for parents to seek medical help, and it may just be that they're sensitive to cow's milk. The symptoms of cow's milk protein allergy overlap and may coexist or complicate curd, reflux. Even if there's no formal dairy allergy per se, there appears to be some kind of cow's milk hypersensitivity among many infants and children with severe reflux. There's all sorts of invasive tests you can do, like stick pH probes down the poor baby's throat, but probably the most practical test in routine pediatric practice is just a trial of a cow's milk protein elimination diet for two to four weeks in infants with reflux. The gold standard is what's called an Elimination and Re-Challenge Protocol, where you see full resolution of symptoms via strict elimination followed by recurrence of the symptoms on reintroduction of cow's milk protein. And when you do that, take 200 or so infants diagnosed with reflux and then not only put them on a cow's milk-free diet, but then do the challenge test, 85 of the 204 infants with reflux were actually suffering from a cow's milk allergy, or at least hypersensitivity, or something. What we think is happening is that our immune system attacks the bovine proteins, as understandably foreign, triggering an inflammatory response, which like irritates the nerves lining your digestive tract, and that results in abnormalities in the rhythmic contractions of the stomach, triggering the regurgitation. When I'm just talking about formula-fed infants, cow's milk protein allergy can occur in exclusively breast-fed infants as intact cow's milk proteins can be secreted in breast milk. If the mom drinks milk or eats eggs, it can get into her baby. Cow's milk protein and other foreign proteins can pass into human breast milk. So breast-fed infants with regurgitation and vomiting may therefore benefit from a trial of withdrawal of cow's milk and eggs from the maternal diet. And indeed, that is now the consensus recommendation of both the North American and European society for pediatric gastroenterology, hepatology, and nutrition. Any time you see reflux, let's first try a therapeutic trial of either cow's milk protein-free formula or, for infants who are breastfed, a maternal strict cow's milk protein elimination diet. And so then we can potentially treat the cause without using unnecessary medications, and certainly before you start considering performing any anti-reflux surgery on the poor kid.