What Really Happens to Your Body When You Take Lactaid

Taking Lactaid with your first bite of dairy at each meal can help prevent stomach pain.
Image Credit: Maskot/Maskot/GettyImages

What Really Happens to Your Body When examines the head-to-toe effects of common behaviors, actions and habits in your everyday life.

If you've ever enjoyed an ice cream cone but then immediately felt your stomach turn, you might be familiar with the ups and downs of lactose intolerance.


About 70 percent of people around the world can't properly digest lactose — a naturally occurring sugar found in most dairy products, per an April 2017 paper in ‌Current Gastroenterology Reports.

Video of the Day

Video of the Day

In fact, experts say the ability to digest lactose after infancy is not as common as you'd think. And with so many dairy-filled food products out there, it's no surprise people with lactose intolerance turn to things like Lactaid pills for symptom prevention and relief.

But what exactly does Lactaid do in your body? And is it safe to take Lactaid pills daily? Here, gastroenterologists and dietitians explain.

What Is Lactaid?

Lactaid is a brand of supplements and food products that have a digestive enzyme called lactase — which your body can make on its own in your small intestine.


Lactase is just one of a few different types of digestive enzymes — i.e., proteins your body makes to break down food and aid digestion. Other enzymes include amylase (which breaks down carbohydrates), lipase (which breaks down fats) and sucrase (which breaks down sucrose), per Johns Hopkins Medicine.

Taking a lactase enzyme supplement would help increase the amount of lactase in your gut, to help you better digest dairy.


While most people's bodies start out making enough lactase on their own, that supply can diminish as you age. In fact, about 30 million U.S. adults have some form of lactose intolerance by the time they're 20 years old, according to the National Institutes of Health (NIH).

You can find Lactaid in pill or chewable tablet form at most pharmacies, or you can buy Lactaid milk, cheese or yogurt products at the grocery store.



Lactose intolerance can also be more common depending on where you're from. For example, people in East Asia, West Africa and parts of Europe — where dairy isn't common — are more likely to have lactose intolerance, per the NIH.

Who Needs to Take Lactaid?

You may need Lactaid pills (or lactose-free food products) if you get stomach pain and discomfort, bloating, diarrhea or constipation after eating dairy-rich foods like cream, milk, cheese or yogurt.


The severity of these symptoms can help you determine whether you need to take Lactaid, especially daily, and whether you have an intolerance vs. full-on milk allergy (which are two different things).


"Lactose ‌intolerance‌ is the inability to absorb lactose in your small intestine," says Kavya Sebastian, MD, a board-certified gastroenterologist and assistant professor at Emory University School of Medicine.

Sometimes, this intolerance can be a result of a GI condition that affects the walls of your intestines, says Ronald Hsu, MD, a board-certified gastroenterologist and clinical professor at the University of California Davis School of Medicine.


"Lactase enzymes are located on the wall of your small intestine, so if the wall is affected by a GI disorder, you may not be able to properly digest lactose," he adds.

Conditions that could lead to lactose intolerance include the following, per Dr. Hsu:

  • Celiac disease
  • Food poisoning
  • Crohn's disease
  • Radiation to the abdomen


Luckily, lactose intolerance from these conditions is often temporary. "It will often go away once your condition is treated," Dr. Sebastian adds.

Underlying condition or not, though, Lactaid can help in these scenarios.

A milk ‌allergy‌, on the other hand, is an entirely different thing. It's an immune system reaction to the ‌proteins‌ in milk (casein or whey), whereas lactose intolerance is the inability to break down the ‌sugar‌ in milk (lactose), Dr. Sebastian says.

People with a lactose intolerance are often able to eat dairy products in small amounts (especially with the help of Lactaid), but people with milk allergies won't benefit from Lactaid and should avoid dairy products altogether.


Another difference? Lactose intolerance symptoms only happen in your GI tract, while milk allergies can cause reactions throughout your body — like hives on your skin, fevers or respiratory issues like difficulty breathing, per the American College of Allergy, Asthma & Immunology.

Your doctor can help you determine whether you have a lactose intolerance or milk allergy through a breath test or blood work, or they can refer you to an allergist for more specific testing.


Anaphylaxis — or trouble breathing — indicates a serious allergic reaction. If you feel short of breath after eating dairy (or any food), call 911 and go to the emergency room immediately to be treated.

What Really Happens in Your Body When You Take Lactaid?

We've learned who may benefit from taking Lactaid, but how exactly does it work in your body? Here are some things it may do:

1. It Can Help You Digest Dairy

In a healthy person, lactose — a sugar naturally found in dairy — is broken down by the lactase enzyme into glucose and galactose. These are then absorbed by your small intestine, according to Nemours Children's Health.

If you have a lactose intolerance, that process is interrupted. Without enough lactase enzymes, dairy is not properly digested and it starts to ferment with the bacteria in your gut, says Alyssa Lavy, RD, a registered dietitian specializing in GI nutrition and owner of private practice Alyssa Lavy Nutrition & Wellness.

"This fermentation process creates gas as a byproduct and draws water into the intestine, which explains the symptoms commonly associated with lactose intolerance, like bloating, cramping, diarrhea and excess gas," Lavy adds.

While Lactaid will help cut down that fermentation, it won't help ‌completely,‌ so it shouldn't be expected to "cure" your lactose intolerance. The severity of your intolerance will also affect how well the supplement works for you.


In fact, a May 2014 study in ‌BioMed Research International‌ reported that lactase supplementation only caused "normal" lactose breath test results in 20 percent of participants, and did not always translate to improved symptoms.

The types of dairy you eat and drink can also affect how well Lactaid works. For example, cow's milk and ice cream tend to have the greatest amount of lactose per serving, while hard, aged cheese and cultured yogurt are naturally low in lactose, according to medical database UpToDate.

All these factors can determine how well Lactaid will work in your body.


According to the National Institute of Diabetes and Digestive and Kidney Diseases, many people with lactose intolerance can have about 12 grams of lactose— or the amount in one cup of milk — without symptoms or only mild symptoms.

2. It Won't 'Cure' Your Intolerance, or Make It Worse

Taking Lactaid will prevent any discomfort while eating dairy, but it won't reverse or "cure" your intolerance.

If anything, continuing to eat small amounts of dairy without lactase supplements may slightly improve your symptoms over time. According to an August 2019 review in the‌ American Journal of Clinical Nutrition‌, this is likely because eating small amounts of dairy changes your lactose-digesting bacteria in your gut, rather than increasing your actual levels of lactase enzyme.

And as far as your body becoming dependent on Lactaid, or it making your intolerance worse?

"We do not have evidence that Lactaid causes dependency, and it's generally recognized as safe for daily use," Lavy says. But you should always talk to your doctor before taking it.

While "some people who use [lactase enzymes] claim they need to continue increasing their dose over time, this is more likely due to aging, as lactase production naturally decreases with age," and not because your intolerance is getting worse, says Erin Lisembly Judge, RD, a registered dietitian who specializes in GI nutrition and is the founder of the practice Gutivate.


This means, you can take Lactaid long term to relieve symptoms, but it won't cure your intolerance or worsen it.

"All we're doing when we use lactase enzymes is giving people something their body is failing to make on its own," Dr. Sebastian says.

Mannitol in Lactaid May Trigger IBS Symptoms

Lactaid’s ‘Fast Act Chewable’ pills are made with a sugar alcohol called mannitol that may not be well tolerated by some people with irritable bowel syndrome (IBS), Lavy says.

“Some people who are sensitive to FODMAPs, or short-chain, fermentable carbohydrates, may be sensitive to mannitol and get symptoms like bloating, diarrhea and excess gas when eating mannitol in foods and supplements.”

This isn’t a huge concern, as there's only a trace amount of mannitol in this product, but it’s still worth pointing out.

3. It Might Help Improve Your Calcium and Vitamin D Levels

Dairy foods and drinks have more calcium per calorie than any other ingredients in a standard diet, according a December 2018 paper in ‌Nutrients‌. Many milk products are also fortified with vitamin D — a key nutrient that can be hard to get from your diet alone.

If you don't make an effort to get calcium and vitamin D from other sources, avoiding dairy products could put you at risk of nutrient deficiencies and bone health issues, according to an April 2019 study in ‌Nutrients‌.

The bottom line: If taking lactase enzyme supplements or eating lactose-free products helps you eat more nutritious dairy products — like organic milk and unsweetened Greek yogurt — then they might just help you fill important nutrient gaps in your diet, per Dr. Sebastian.

How to Take Lactaid Pills

If you want to still enjoy eating dairy, without the discomfort, taking Lactaid pills is a great option. Here are some tips from Judge:

  • Try taking them with your first bite of a dairy food or drink, and take another dose if you're still eating 30 minutes later.
  • The "right" dose of Lactaid will also depend on each person's intolerance level. But the starting recommendation is one 3,000-unit tablet of lactase for every 5 grams of lactose eaten. (For reference, an 8-ounce glass of milk has around 12 to 15 grams of lactose.)
  • You can choose to take Lactaid on certain occasions rather than every day or at every meal (think: on pizza night or at a birthday party with ice cream and cake).


“If you're eating a food with lactose and no added sugar, you can measure grams of lactose by reading the label for grams of sugar, because lactose is the natural sugar found in milk,” Judge says.

If you've already taken the recommended amount and you're still feeling stomach discomfort, an additional food intolerance may be to blame. "Often, we see other food intolerances in combination with lactose intolerance, including sucrose-, fructose- and other FODMAP intolerance," Judge says.

And Dr. Sebastian says that if you're not feeling a difference from taking Lactaid, then there's no reason to continue taking it. If this is the case for you, go to your doctor and see if they can recommend something else.

Alternatives to Taking Lactase Enzymes

Even though it's generally safe to take Lactaid supplements every day, you may decide that alternative options are a better choice for you. If that's the case, you can try the following strategies to prevent lactose intolerance symptoms:

1. Choose Low-Lactose Dairy

Certain dairy products are naturally lower in lactose than others. This includes:

Products that have lactobacilli bacteria (like yogurt) may help mild forms of lactose intolerance because they decrease the amount of lactose that actually gets fermented in the gut. As a result, they reduce the likelihood of gas and diarrhea, Dr. Hsu says.

Plus, the probiotics found in products like kefir have been shown to alleviate symptoms of lactose intolerance, per a February 2018 review in ‌Critical Review in Food Science and Nutrition.

2. Try Lactose-Free Products

If you're looking for something mostly lactose-free, try dairy products that already have lactase enzymes added to them.

Turns out, some manufacturers don't actually take the lactose out of milk. They simply add lactase enzymes to products so the lactose is basically pre-digested for you, per Yale Scientific.

This is a lot like taking a Lactaid pill alongside your glass of milk, only the pills' contents are already added to the milk itself.

And don't be surprised if they have a slightly different flavor.

"Lactose-free milk can taste really sweet because the lactose has already been broken down into glucose and galactose, and simple sugars taste a lot sweeter," Dr. Sebastian says.

3. Experiment With Your Tolerance Levels

If you feel your body can handle it, try slowly introducing small amounts of dairy foods to figure out what portion sizes work best for you. You may feel initial discomfort at first, but over time, you'll learn what your body can tolerate.

Ultimately, you may need to limit or avoid dairy products if you feel discomfort every time.

The Bottom Line

Lactaid is a supplement that can help you better digest dairy, allowing you to eat more foods you enjoy. It won't cure your intolerance or make your body dependent on it, but it's generally safe to take every day.

"As long as it's used as directed, Lactaid is reasonably safe and is good to try if you're lactose intolerant but still want to eat dairy," Dr. Sebastian says.

And if you've never been diagnosed with lactose intolerance, but feel stomach pain, bloating or diarrhea after eating dairy, talk to your doctor. They can help you figure out the cause and come up with a treatment plan.




Is this an emergency? If you are experiencing serious medical symptoms, please see the National Library of Medicine’s list of signs you need emergency medical attention or call 911.