How Lactase Enzyme Impacts Lactose Intolerance, and Ways To Manage Side Effects

Do you hesitate to satisfy your dairy cravings? Worry you might be sensitive to lactose? Then it’s a good time to learn more about lactase — the natural enzyme responsible for lactose digestion — and how you can manage your tolerance.

Because even if you’re lactose intolerant, consuming dairy foods doesn’t have to cause the bubble guts. When consumed strategically, dairy can be the perfect solution to help overcome lactose digestion woes.

The Difference Between Lactase vs. Lactose

While similar in name, there’s a big difference between lactose and lactase.

Lactose is the natural sugar in milk and other dairy foods made from milk. It consists of two linked sugars, glucose and galactose.

Lactase is the natural enzyme our bodies make and use to digest lactose. It breaks the combo sugar back down into glucose and galactose, making it easier for our bodies to process.

So, as different as they are, lactose and lactase are designed to go together. Which is why our bodies can become sensitive to lactose when we don’t have enough lactase.

How the Lactase Enzyme Impacts Lactose Intolerance

Lactase is needed to break down and digest lactose. So a lack of it can make lactose much more difficult for our bodies to handle. In fact, having an insufficient amount of lactase can lead to digestive conditions such as lactose malabsorption and lactose intolerance.

“Lactose malabsorption means your body has a lower threshold for digesting lactose because the lactase enzyme might have low activity,” says Kerry Hackworth, MS, RD, LDN, senior director of nutrition affairs at National Dairy Council (NDC). “Lactose intolerance, on the other hand, describes the physical symptoms (like stomach pain, bloating, gas or diarrhea) that start after eating more lactose than your body can digest and absorb.”

So, lactase has a tremendous impact on whether someone will become lactose intolerant. The less lactase your body has, the more likely you’ll have digestive symptoms. The more lactase your body has, the more likely you’ll be able to consume lactose-containing foods without a second thought.

Can You Suddenly Become Lactose Intolerant?

While rare, it is possible to suddenly become lactose intolerant — even if you’ve always had high lactase levels.

“Acute cases of lactose intolerance can occur during a bacterial, viral or parasitic infection that can cause a temporary loss in the function of lactase,” Hackworth explains. But this isn’t necessarily permanent. “After the person gets better from their sickness, lactose digestion is usually restored.” 

These acute cases aren’t something you need to stress about, however. “In general, lactose malabsorption happens with increasing age,” Hackworth says. Same goes for lactose intolerance.

So while it can be common to feel like you became lactose intolerant out of nowhere, it’s far more likely that this intolerance developed gradually as your lactase levels naturally declined.

How Lactase Levels Naturally Change Over Time

Lactase levels generally decline as we age, though at varying rates based on key factors such as genetics. But across ethnic groups and regardless of a family’s dietary lifestyle, our bodies mostly produce a significantly high amount of lactase in the early years.

“It is important to note that the lactase enzyme is very high in infants and young children as breast milk has higher concentrations of lactose than cow’s milk,” Hackworth says. A big reason why “it is rare for young children to be lactose intolerant.”

Our lactase levels eventually fall because our bodies stop producing it at the same rate as when we were younger. But exactly when this happens will vary person by person and, more broadly, by ethnic group based on genetics. For instance, Harvard Health reports that many people of African and Asian descent start making less lactase at around age 5, whereas 80% of Caucasians have a gene that preserves the ability to produce lactase into adulthood.

This ultimately contributes to the prevalence of lactose conditions in some communities and its rarity in others all around the world. “In Europe, lactose malabsorption is reported in only 10% of adults,” Hackworth says. “And in Asian countries, close to 99% of adults may have lactose malabsorption.” Similarly, Harvard Health reports that 65% of Africans and African Americans have some degree of lactose intolerance.

But your lactase level in adulthood isn’t limited to a genetic luck of the draw. No matter your ethnicity, it may be possible to increase your lactase enzyme and improve your lactose digestion — even if you’re lactose intolerant.

How to Increase Your Lactase Enzyme and Improve Lactose Digestion

One common approach is to increase your lactase enzyme with supplements. 

“When someone with lactose intolerance takes a lactase supplement, they’ll be able to comfortably eat higher lactose-containing foods,” says Amanda Sauceda, MS, RDN, owner of The Mindful Gut. But they have to make certain considerations, such as timing. “For a lactase supplement to be most effective, you want to take it at the start of the meal.”

Sauceda says another thing to be aware of is that “lactase supplements don’t cure lactose intolerance.” So, while they have their benefits, lactase supplements are limited in how much they can assist someone. Plus, “it can be inconvenient to always have some on hand.” 

Fortunately, however, lactase pills aren’t the only way to increase your lactase enzyme. There’s another, more natural approach that can have an even greater and longer-lasting impact: dairy-based dietary adjustments.

Ironic as it may be, the strategic consumption of dairy might be a way to naturally increase your tolerance to lactose.

If you’re wondering how to increase lactase enzymes in your body naturally, “there is emerging research to show that people who have less lactase enzyme may benefit from inclusion of lactose-containing dairy foods,” Hackworth reveals. “Lactose may promote the growth of lactase-digesting bacteria in your colon and may help lower symptoms of lactose intolerance.” This is a process known as colonic adaptation.  

Notably, however, this doesn’t mean you should start eating as many different lactose-containing dairy foods as you can find — especially if you’re lactose intolerant.

As Sauceda frames it, “You do need to be intentional about increasing lactose foods. You can’t just eat lactose-containing foods occasionally with the hopes of increasing lactase. By being intentional, you could help build up your tolerance to lactose-containing foods.”

Dairy Foods to Help Naturally Manage Your Lactose Tolerance

Different dairy foods have different amounts of lactose. And when you’re just starting your journey to higher tolerance, the dairy foods with higher amounts of lactose may be too much too soon and overwhelm your body. It’s better to start slow and ramp your way up.

“Starting with foods on the lower end of the lactose spectrum will be helpful,” Sauceda says. “Cheeses like cheddar or mozzarella are a nice place to start. Then you can move up to ricotta cheese or cottage cheese.”

Yogurt and kefir are also great starting points. Yogurt and kefir have been shown to improve lactose tolerance, and that yogurt in particular has live and active cultures that break down lactose, acting similarly to the lactase enzyme. Importantly, both yogurt and kefir are also low in lactose. In fact, most plain, low-fat yogurt has just 4 grams of lactose per serving, while plain low-fat kefir has 8 grams per serving — far less than the 12 grams of lactose most people with lactose intolerance can consume without symptoms. And these aren’t the only reasons the two dairy foods are lactose-friendly.

“Yogurt is a great option for people with trouble digesting lactose because the live and active cultures in some yogurts may help your body better break down lactose,” Hackworth says. An advantage that holds true with kefir as well.

By intentionally starting with cheese, yogurt and kefir — and using other lactose-friendly tips to enjoy your favorite dairy foods  — you can improve your lactose tolerance.

“By increasing lactose digestion naturally, you can have more spur-of-the-moment opportunities to eat lactose-containing foods,” Sauceda says. “You can also have a higher tolerance for foods that you may not have known had lactose in them. This would be helpful when you’re eating out and don’t know all the ingredients in your meal.”