Until I hit puberty, I was allergic to milk. When I explained why I had turned down both the pizza and the ice cream cake at a birthday party, people would nod knowingly and say, “Oh, lactose intolerance.” I admit I got a little tired of having to clarify, “No, milk allergy. I get hives, not just an upset stomach.”
It’s an understandable mistake. Unfortunately, a whole bunch of people who should know better, including pediatricians, still have trouble telling the difference. As a result, otherwise healthy infants are regularly being diagnosed with “lactose intolerance” – which is basically a scientific impossibility.
To navigate the spectrum of reactions to dairy, you first need to know something about what’s in nature’s baby food. Breast milk has several components: vitamins and minerals (most famously calcium); fat, known to you and me as butter; proteins (casein and whey are the prominent ones in cow’s milk); and milk sugar, known as lactose.
Proteins and lactose are usually the two troublemakers, but for very different reasons. What we usually think of as lactose intolerance appears only in older kids and adults.
Click to view chart. A crucial distinction between them is that proteins differ between different mammals’ milk, but lactose is lactose is lactose. Lactose only varies in quantity: the proportion of lactose in milk increases with the size of a species’s forebrain, notes Linda Folden Palmer in her book Baby Matters, so human milk actually has more lactose than any other kind. (In other words, breastmilk is sweeeet!)
This means a condition in which a baby couldn’t digest lactose would have been fatal up until very recently. A couple of such recessive genetic conditions do exist, but they are very rare and are identified within weeks, if not days, of birth, because babies who have them will fail to gain weight or thrive until put on a lactose-free diet. This is known as “congenital” lactose intolerance.
What we usually think of as lactose intolerance appears only in older kids and adults. Mammals usually start to lose the ability to produce lactase, the enzyme that digests lactose, around the time they wean. (This is why you can give milk to kittens but not to adult cats.) Without lactase, if you drink straight-up milk or other dairy that still has lactose in it (butter and most cheeses don’t), you get uncomfortable bloating, cramps, nausea, or diarrhea from the undigested sugar in your gut.
Click to view chart. Some pockets of humans (Caucasians mostly) who relied on domestic livestock developed the unusual ability to keep producing lactase into adulthood. In an ethnocentric moment, these milk-drinkers assumed this ability was the norm and named the other 75 percent of the world’s population “lactose intolerant.” This kind of lactose intolerance usually doesn’t show up until age four or five, often much later.
If you do the math, you will notice that neither of these conditions would apply to healthy infants. And yet, infants who are colicky, have reflux, or show other signs of gastrointestinal distress are being diagnosed as lactose intolerant all the time, sometimes officially by doctors, sometimes informally by concerned parents.
“A lot of mothers don’t know that breastmilk does have lactose,” explains Chana Sidi, leader of the Delmar, New York, La Leche League. “There is a confusion about the age of onset [of lactose intolerance],” agrees Dr. Dan Thomas, a pediatric gastroenterologist at Children’s Hospital in Los Angeles.
“It happens in the community all the time,” says Dr. Jatinder Bhatia, chief of the neonatology section at the Medical College of Georgia and a member of the American Academy of Pediatrics’ nutrition committee. Bhatia says he takes great pains to try to correct misinformation about lactose in his hospital practice and through collaborating on education campaigns, and notes, “As a matter of fact, formulas that have reduced lactose or claim to be lacto-free are not even stocked in my nursery.”
Bhatia and his colleagues have got their work cut out for them, apparently. Nearly a quarter of babies in the United States are on soy formula (as compared to two-to-three percent in the U.K. and Australia). Rowena Bennett, a registered nurse and midwife in Australia for thirty years who has a consulting business helping primarily American parents with irritable or uncomfortable babies, reports that “lactose intolerance has always been in the top four medical diagnoses given for unexplained infant crying and sleep disturbance for as long as I am aware.”
If these diagnoses are actually impossible, then what’s going on with those babies?
Some of them have a cow’s milk allergy. An allergy is a mistaken immune-system response to proteins. Since proteins differ between different mammals’ milks, babies can be allergic to cow and even goat milk, while being fine with breastmilk – as long as the nursing mother hasn’t been eating dairy herself, since cow’s milk proteins will enter the breastmilk.
“Milk allergy is the most common food allergy in young kids,” says Dr. Anna Nowak-Wegrzyn, assistant professor of pediatrics at the Jaffe Food Allergy Institute of the Mount Sinai School of Medicine. “It affects 2.5 percent of kids. If these diagnoses are actually impossible, then what’s going on with those babies? If these diagnoses are actually impossible, then what’s going on with those babies? Milk allergy can give you GI symptoms, but it will also give you skin symptoms like hives, eczema, runny nose.” Milk allergies can range from severe (anaphylactic shock from trace amounts) to mild (discomfort that may never be recognized before a child outgrows it). With an allergy, reactions also happen almost immediately, she says, rather than the two or so hours it takes for gas to form from undigested lactose. An allergist can help you diagnose a milk allergy.
To make things more complicated, there is also a kind of milk allergy that only generates GI discomfort, not skin symptoms, and won’t show up on tests. And one of the things such an allergic reaction does is damage lactase-producing cells, causing lactose-intolerant symptoms. This kind of allergy is hard to diagnose, but if the symptoms are alleviated when a nursing mother removes all traces of dairy from her diet for at least two weeks, that’s a good sign. Fortunately, says Nowak-Wegrzyn, “most of those GI allergies go away in the first year of life.” While some foods cause various non-allergenic problems for people who are “sensitive” or “intolerant” to them, Nowak-Wegrzyn says if milk causes a problem, it’s pretty much either lactose intolerance or an allergy.
While milk allergy, unlike lactose intolerance, is a condition that really does affect a significant number of infants, it too may be less common than some of us think. A recent study of 800 families in the U.K. found that food allergies are not increasing in the same way that asthma and other allergies are, but that parents have become more aware of them and are seeing them even when they’re not there. The study’s senior researcher told BBC News that “Mums tend to put down every rash, tummy ache, diarrhea and crying to food allergy or intolerance.”
Bennett has an idea of one possible culprit. She says doctors, who are not trained in the subtleties of infant development and feeding techniques, tend to overlook a common problem that mimics lactose intolerance: lactose overload, or simply “overfeeding.” (La Leche League calls it “oversupply” or “foremilk/hindmilk imbalance.”)
Inaccurate diagnoses of lactose intolerance can lead to early cessation of breastfeeding. Lactose overload occurs when a baby gets so much lactose that it can’t make enough lactase to keep up, resulting in undigested lactose and all the symptoms of traditional lactose intolerance (including positive results on tests for lactose intolerance designed for adults). This can happen when a mother has an abundant milk supply and switches sides often, before a breast is empty, so her baby is always getting mostly lactose-rich foremilk and not enough of the fatty hindmilk. It can also happen to formula-fed babies who get too much formula at a sitting. To relieve their upset stomachs, babies with lactose overload ask for more milk even when not hungry, adding even more lactose to their systems and making a vicious cycle.
The treatment for lactose overload is changing feeding patterns: not switching sides until a breast is drained (or even nursing on one side for more than one feeding) or giving less formula.
Although child health specialists like Bennett and online parenting gurus like Kellymom consider this phenomenon to be widespread, many pediatricians seem not to have heard of it at all. Inaccurate diagnoses of lactose intolerance can lead to early cessation of breastfeeding. In fact, Dr. Bhatia, who is a liaison between the Medical College of Georgia’s sections on neonatology and breastfeeding, told me he was not aware of it, though he does counsel mothers to empty one breast before switching sides.
All these subtleties matter. (See our handy chart for a side-by-side comparison.) Inaccurate diagnoses of lactose intolerance can lead to early cessation of breastfeeding, with babies switched to expensive and nutritionally inferior lactose-free formulas. Misdiagnosed lactose intolerance (or milk allergy) can also lead to “unnecessary dietary restrictions that can sometimes last a lifetime,” notes Bennett. “Milk and dairy are a prime source of calcium for children.” Not to mention, “many adults who believe they are lactose intolerant believe this because it was misdiagnosed in infancy.”
Milk – ours and other mammals’ – is a fascinating and nearly magical substance. But as herbalists know, anything powerful can also cause problems. When it comes to our kids and milk, it’s worth it to know what those problems are – and what they aren’t.