You sink your teeth into a grilled cheese from your nearest comfort food joint. That first bite leaves you parched, so you chase the umami with a cold glass of milk. On your way home, you treat yourself to some ice cream, a Friday reward after a successful week.
Unfortunately, all the joy in the world couldn’t compensate for the cramps, bloating and bathroom torture you’ll endure thanks to this dairy joyride.
Sounds familiar, right? Despite the ubiquity of dairy at grocery stores and restaurants, tens of millions of people in the U.S. are lactose intolerant. Let’s explore what, exactly, the term means, what causes lactose intolerance and how to avoid hurting your gut too much in a dairy-rich world.
What Is Lactose Intolerance?
Simply put, lactose intolerance refers to a person’s inability to properly digest, or break down, lactose, a sugar found in dairy products like cheese and ice cream, in addition to many processed foods, like cereal. Those with the condition may experience certain symptoms — like bloating, gas and diarrhea — after eating foods containing lactose.
Lactose is a disaccharide, meaning it is composed of two types of simpler sugars, glucose and galactose, that are bound together. These form long chains, or polymers, in food. But the unique structure of these glucose-galactose chemical bonds necessitates a specialized tool to properly snip these molecular ribbons apart.
Enter lactase, an enzyme designed to do just that. And virtually every human on Earth carries the genes to create it. The real hangup comes from our body’s ability (or inability) to produce sufficient enough amounts to process those cheesy cheat days.
What Causes Lactose Intolerance?
In gastrointestinal tracts with functioning lactase, the inflow of lactose is broken down in the small intestine into easily absorbed sugars, clearing the way to the colon. In those with lactose intolerance, the undisturbed lactose makes its way into the large intestine, where a motley assortment of gut microbes makes eager work of it.
Unfortunately, instead of generating byproducts that benefit our bodies, for those with lactose intolerance, these gut bacteria produce gas and acidic compounds, leading to bloating, cramps, excessive flatulence, and diarrhea.
Most of these bacteria are fermenters, capable of digesting sugars like lactose anaerobically, or without oxygen. But, unfortunately for your stomach, the key byproducts of this reaction include hydrogen gas and acidic chemicals. Around 4 in 5 people produce hydrogen during this anaerobic digestion process, and a breath test can be used to assess the degree to which their dairy consumption has stimulated their gut flora.
How To Test for Lactose Intolerance
However, Jeffrey Nathanson, a gastroenterologist at Comprehensive Gastrointestinal Health in Northbrook, cautions against using breath tests as a de facto diagnostic tool. “1 in 5 people are methane producers,” Nathanson says. “Their gut flora are generating methane as a byproduct of their anaerobic digestion, not hydrogen.”
Nathanson says that simply assessing your symptoms as you age provides a decent proxy for determining whether or…