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How To Know If You’re Lactose Intolerant

If you have one of these four symptoms, you might want to consider ditching dairy.

With your run of the mill food allergy, it’s usually pretty obvious what’s going on. The scene probably looks something like this: Food goes into your face, then all of a sudden your mouth is itchy, or you break out in hives, or worse. The culprit is clear. Lactose intolerance, on the other hand, can be a little bit trickier to detect. What’s more, it can sneak up on you after years of enjoying cream, cheese, butter, and other heavenly treats like it’s your job. Here’s what you need to know about lactose intolerance, and how to know if you might have trouble digesting dairy.

Lactose intolerance is really common—and you aren’t always born with it.


If you’re lactose intolerant that simply means your body doesn’t produce enough or any of the lactase enzyme, which makes it harder for you to process lactose, the sugar found in dairy products. If you’ve been lactose intolerant forever, then you probably know all about this. But if you’ve never had problems throwing back mac and cheese before, and suddenly feel wonky afterward, Michelle Cohen, M.D., a gastroenterologist at Mount Sinai, Brooklyn Heights, tells SELF that there are a couple reasons this may be happening.

Cohen says that as we get older, our GI tract produces fewer enzymes—meaning that with every year that passes you become more susceptible to developing lactose intolerance. In fact, about 30 million Americans have some degree of lactose intolerance by the time they turn 20, according to the National Institutes of Health.

Cohen also explains that if you’ve recently had diarrhea, or some other gastrointestinal illness that may have damaged your GI tract, you may experience temporary lactose intolerance. And as soon as your GI tract heals—which can take a couple days to a couple weeks—she says you should go back to normal.

The symptoms of lactose intolerance aren’t the same for everyone, but there are four ways it usually affects you.

According to Cohen, bloating, gas, and abdominal pain are some of the most common symptoms of lactose intolerance. She explains that, because you don’t have that enzyme to break down the lactose, the bacteria in your gut is going to interact with it. That interaction will lead to fermentation which she explains will create a lot of gas—and that trapped gas may cause bloating or abdominal pain.

Diarrhea is also extremely common. Because your body isn’t breaking down that lactose, there’s an increased amount of sugar just sitting in your GI tract. Cohen explains that, “increased sugar can lead to more water in your GI tract,” and that extra water can lead to diarrhea.

The combination and intensity of these reactions differs from person to person, but typically kick in about 30 minutes to 2 hours after eating milk products.

Some people can’t eat any dairy at all, while others find that only certain items give them tummy troubles.

According to the NIH, “most people with low lactase levels can drink up to one-half cup of milk at one time (2 to 4 ounces) without having symptoms.” But take a tally of your Lactaid-toting friends and you’ll probably find a wide range of sensitivities. One person might be able to enjoy an ice cream cone on a hot day, while another gets the runs after a sip of a milkshake.

There are some dairy products that are often better tolerated than others. These include buttermilk and buttermilk cheeses, as well as hard and aged cheeses (because they contain less lactose than regular milk), and goat’s milk. Brunilda Nazario, M.D., an associate medical editor at WebMD, say that fermented dairy products like yogurt and kefir may also be easier on your stomach, because that fermentation process helps break down the lactose so you don’t have to.

One surefire way to dodge lactose-intolerance troubles? Skip the dairy altogether. Nazario says your best option is to opt for dairy-free alternatives, which often taste just as good as the real thing.