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What is Lactose Intolerance?

Published on: February 4, 2023

Lactose intolerance is a common condition that affects 70% of the adult population worldwide (1).

Wait, does that mean that you should be worried? Are there any good lactose-free options out there? Do you need to go dairy free now?

Keep reading to find out everything you need to know about lactose intolerance. 

What is lactose? 

Lactose is a naturally occurring sugar found in dairy. It is composed of two sugars, galactose and glucose.

What is Lactose Intolerance?

Lactose intolerance is a non-immune-mediated reaction that can lead to unwanted GI symptoms (1). Further, lactose intolerance is an inability to produce sufficient amounts of the enzyme lactase, which breaks down lactose (a type of naturally occurring sugar found in dairy).

Low lactase levels cause lactose to ferment in the gut and cause GI symptoms.


  • Abdominal Pain
  • Bloating
  • Gas 
  • Diarrhea 
  • Nausea 
  • Vomiting 
  • Discomfort 

Intolerance Levels

“A recent meta-analysis showed that almost all lactose intolerants tolerate 12 g of lactose in one intake and approximately 18 g of lactose spread over the day” (1). 

“Diets with low levels of dairy product intake have been associated with increased risk of osteoporosis” (1).

Types of Lactose Intolerance

Primary Lactase Deficiency

Primary lactase deficiency is a genetic deficiency of lactase causing lactose intolerance (1). Primary lactase deficiency is the most common form of lactose intolerance. It develops early when lactase levels are high in childhood and then sharply decline into adulthood.

There are two forms of primary lactase deficiency: Congenital Lactase Deficiency (CLD) and Lactose Non-Persistance (LNP). 

CLD is severe but rare and only occurs in newborns. In CLD, lactase levels are extremely low or non-existent (2).

LNP is less severe than CLD and more common. Onset typically occurs in toddlers and generally is fully developed during the preadolescent years.

Secondary Lactase Deficiency 

It is related to various diseases that prevent the body from producing sufficient lactase enzymes. Conditions that may cause lactase deficiency include Chron’s disease, chemotherapy treatment for cancer, surgery of the intestine, and chronic intestinal inflammation, to name a few (1).

In these cases, lactose deficiency may only be temporary, and once the intestine wall heals, regular lactase activity resumes (1). 

Lactose Intolerance or IBS? 

Lactose Intolerance reports may be higher than actual numbers. One reason may be the confusion between lactose intolerance and Irritable Bowel Syndrome (IBS) (1).

Individuals with IBS typically suffer from similar symptoms. Further, testing for IBS is tricky; thus, it can be challenging to tease apart lactose intolerance or an IBS diagnosis. 

Individuals with IBS can have a variety of food triggers that may or not be related to lactose. If you have been tested for lactose intolerance but do not have it and are still experiencing similar symptoms, please contact your doctor to inquire about testing for other GI conditions.

Who does it affect?

Let’s be clear; lactose Intolerance can affect anyone. However, there is a solid link to the prevalence of lactose intolerance in particular populations. Asians, followed by Africans and Latinos, have the world’s highest rates of lactose intolerance. (1).

Higher rates of lactose intolerance occur in areas where milk consumption is low (1).

How is it different from a milk allergy?

A milk allergy is an immune reaction to dairy that can be life-threatening. 

Unlike lactose intolerance, you must avoid all dairy and dairy products if you have a milk allergy.


Your doctor determines a lactose intolerance diagnosis via a blood test, hydrogen breath test or biopsy (2). Your doctor may also make a diagnosis based on your symptoms.

Note a lactose intolerance diagnosis is very different from a milk allergy diagnosis. If you are suspecting of either, reach out to your doctor.


There are several ways to help treat lactose intolerance which include: 

  • Avoiding or limiting lactose-containing foods that cause discomfort
  • Using supplements that help to break down lactose
  • Medications 

Foods to Limit

Lactose intolerance works on a sliding scale. For example, you may experience symptoms with half a cup of yogurt, and your friend who is also lactose intolerant may experience none from that same amount of yogurt.

Thus, when it comes to limiting foods, food type and amount will vary for each individual.

Here is a list of some common foods that cause discomfort and may be worth limiting or, in some cases, avoiding:

  • Milk 
  • Yogurt
  • Soft cheeses 

Ingredients to Limit

  • Milk curds
  • Whey 
  • Milk solids
  • Milk powder


Lactase Enzyme

Lactase enzymes are made up of lactase and can be taken with lactose-containing foods to prevent unwanted symptoms. A lactase enzyme replaces lactase when your body can’t make enough of it on its own. 


Some research points to particular probiotics that may help reduce common lactose intolerance symptoms.

In particular, the probiotics that appear to reduce the symptoms included bacteria from the following species (2):

  • L. acidophilus, L. reuteri, L. rhamnosus, and L. bulgaricus, S. thermophilus, and B. longum

It’s important to note that probiotics work best at specific doses and in specific combinations to help alleviate symptoms of lactose intolerance.

If you want to try a probiotic to reduce your symptoms, reach out to your healthcare provider to discuss if this is the right option. 

Research around probiotics is still relatively new, and the best way to avoid unwanted symptoms is through limiting foods containing lactose or choosing lactose-free options. 


Prebiotics act as fuel for the good bacteria in our gut. Prebiotic supplements are currently being explored as a possible treatment for lactose intolerance.

However, at this time, there is no conclusive evidence to support the use of prebiotic supplements to help reduce symptoms in individuals with lactose intolerance (2). 


Some medications may contain small amounts of lactose. Talk to your doctor if you are concerned. Typically small amounts of lactose do not cause unwanted GI symptoms in those with lactose intolerance.

What Foods Can You Eat if you are Lactose Intolerant?

Lactose-Free Food Swaps

  • Dairy Milk → Vegan milk or Lactose-free milk 
  • Sour cream → Lactose-free sour cream 
  • Cheese → Lactose-free cheese, soy cheese and cashew cheese
  • Yogurt → Lactose-free yogurt, soy yogurt, almond yogurt, coconut yogurt
  • Butter → Plant-based margarine 

Choosing dairy-containing lactose-free options is preferable to vegan options as they are a good source of essential nutrients like:

  • Protein
  • Calcium
  • Vitamin D
  • Vitamin A
  • Potassium

However, many vegan or plant-based options provide similar types and amounts of nutrients comparable to dairy-containing lactose-free products. Work with your dietitian to ensure you are meeting your nutrient needs.

Calcium and vitamin D, in particular, are nutrients we typically get from dairy products. So, here are some lactose-free sources of calcium and vitamin D


  • Lactose-free milk 
  • Fortified soy milk
  • Fortified pea protein milk 
  • Lactose-free yogurt
  • Coconut yogurt 
  • Canned salmon 
  • Calcium set tofu 
  • Almonds
  • Collard greens
  • White beans 
  • Broccoli 
  • Tahini 

Vitamin D

  • Fortified plant-based milk 
  • Mushroom
  • Enhanced eggs

Vitamin D is difficult to get from food alone. Talk to your health care provider about a vitamin D supplement if you need to consume more vitamin D. Particularly in Canada, during winter, your body cannot make adequate amounts of vitamin D from the sun.

Foods low in Lactose 

Much to your surprise, you may be unaware that there are dairy products low in lactose that some may tolerate. Tolerance will vary from person to person, but typically, the following low-lactose foods are tolerated by most people with lactose intolerance:

  • Hard Cheeses (cheddar, swiss, mozzarella, parmesan) 
  • Yogurt 
  • Ricotta cheese
  • Cream cheese 
  • Cottage cheese

Note, when it comes to lactose serving size matters. For example, you may tolerate one ounce of hard cheese but not two, or ½ cup of ricotta cheese but not ¾ a cup.

Bottom Line

You do not need to avoid lactose-containing products unless you have a dairy allergy or lactose intolerance, as dairy is a good source of essential nutrients. 

If you choose to avoid lactose-containing products for other reasons, reach out to a registered dietitian to ensure you are meeting your overall nutrient needs.

Are you looking for more lactose-free options? We’d love to hear from you; contact us for more tips!


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Kelsey Moore Registered Dietitian Headshot

Hi I’m Kelsey!

I’m a Registered Dietitian working in the retail grocery industry. I help families find allergen-free foods at the grocery store while saving them time and money.

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