Lactose Intolerance vs Dairy Sensitivity

Lactose Intolerance vs Dairy Sensitivity: How to Tell Them Apart

If you suspect you have some “dairy issues” and you’d like to learn how to tell the difference between a lactose intolerance vs dairy sensitivity, look no further!

In this article we’ll explore all things lactose and dairy in-depth from a holistic and functional nutrition lens, so you can get crystal-clear on what’s going on in your body and make more informed food choices.

Disclaimer: This is not medical or nutritional advice! The information shared in this article is meant to be educational and informative regarding how to identify and navigate lactose intolerance vs dairy sensitivity. Consult a doctor and a registered dietitian or holistic nutritionist to get customized gut health nutrition advice.

Affiliate disclosure:  This article contains affiliate links*.  As an Amazon Associate, I may make a commission on qualifying purchases at no extra cost to you!

Milk, dairy, and gut health

To clarify, lactose, milk, and dairy products in general aren’t inherently bad. Our ancestors consumed this stuff for over thousands of years without many issues!

Not to mention, dairy is also very nutrient-dense. It’s packed with bone-building and energy-metabolizing micronutrients such as calcium, phosphorus, and B vitamins.

(On the other hand, by no means am I endorsing the modern-day commercialized, unethical, unsustainable, corn-centric GMO “farming” practices currently in place among companies that mass-produce mainstream dairy. But that’s a conversation for another time.) 😉

Either way, the unfortunate reality is that many people suffering from gut issues like irritable bowel syndrome (IBS), small intestinal bacterial overgrowth (SIBO), and/or inflammatory bowel disease (IBD) can’t enjoy a glass of milk (or in some cases, dairy products in general) without some kind of unpleasant consequences.

This is due in part to a few very specific underlying types of adverse food reactions:

  • Lactose intolerance
  • Milk/dairy sensitivity

Lactose intolerance 101

The most common reason so many people with IBS can’t enjoy a “normal” glass of milk without spiraling into a flare is because of a condition called lactose intolerance – aka an inability to break down milk sugars in the gut.

  • While you can technically be “lactose-intolerant” and not have IBS, I know very few (if any) IBS sufferers who don’t have a lactose intolerance.


Lactose intolerance tends to manifest as a cluster of symptoms, such as:

  • Gas
  • Bloating
  • Cramping
  • Diarrhea

…usually occurring within a window of ~30-90 minutes after consuming any kind of dairy that contains lactose.

What is lactose?

Lactose is a type of “milk sugar” only found in mammalian milk.

  • It’s supposed to get broken down in the gut, primarily by an intestinal brush border enzyme called “lactase.” (1)
  • Lactose can also get digested by certain types of probiotic microbes which live in the gut and/or which can come from probiotic foods/supplements such as yogurt, probiotic sauerkraut, or probiotic pills. (2, 3)

What causes lactose intolerance?

Unfortunately, not everyone makes enough lactase enzymes in their intestines, and not everyone has enough healthy lactic acid probiotics in their gut or in their diet.

Lactase enzyme deficiency

Lactose intolerance is most often the result of insufficient lactase enzyme levels in the intestines.

  • Some people are genetically at a disadvantage in that their body just isn’t hardwired to produce lactase enzymes. (4)
  • Others have an acquired lactase deficiency which is caused by cellular damage to the intestinal brush border, through which lactase enzymes are supposed to get produced and released. (1, 5)
    • Damage to the brush border is caused by underlying microbial imbalances left unchecked, such as SIBO. (5)

Gut dysbiosis

It’s interesting to note that most people who are lactose intolerant can still eat moderate amounts of fermented milk products like yogurt and kefir without reacting – and that’s no coincidence!

People who have IBS also usually have some underlying dysbiosis – aka not enough “good” probiotic, healthy microbes in the gut, combined with an overgrowth of “bad” pathogenic, troublesome microbes which lead to IBS symptoms. (6, 7, 8)

And we know that certain types of probiotic microbes (like certain strains of Lactobacillus bacteria) help us to break down lactose. (9)

  • People with dysbiosis tend to have lower counts of Lactobacillus in their gut, based on GI mapping with clients in my functional nutrition clinic.

No wonder why so many people can’t break down lactose!

What happens when lactose isn’t broken down?

If you don’t have enough lactase enzymes and/or probiotic microbes in your gut to properly break down the lactose, those undigested milk sugars are a recipe for turbulence in your gut…

  • When undigested lactose enters the colon, we see an osmotic effect.
    • Large amounts of water get pulled into the colon, inevitably causing diarrhea and all the other unpleasant symptoms that go along with it!
  • For people with SIBO, undigested lactose can also get fermented by “bad” microbes in the intestines which will then produce hydrogen and/or methane gas, and subsequent IBS symptoms.

Dairy for lactose intolerant folks: what can we eat?

The nice thing about only having a lactose intolerance (versus a dairy sensitivity) is you can usually still enjoy most or all lactose-free foods in moderation, such as:

  • Lactaid milk (milk pre-treated with lactase enzymes)
  • Low FODMAP yogurt
  • Hard cheeses
  • Ghee (clarified, 100% lactose-free butter)
  • Butter
    • Note:  the amount of lactose (natural sugar) in butter is very negligible.  For this reason, butter seems to be well-tolerated by most but not all people with lactose intolerance, based on my own first-hand clinical nutrition observations over the years!

Recommended reading:

What about soft cheeses?

Soft cheeses like cottage cheese, cream cheese, feta, brie, goat cheese and mozzarella naturally contain small amounts of lactose. 

These cheeses have more lactose than butter, but a lot less than what’s in a glass of milk!

If you check out the total grams of sugar per serving on the nutrition label of a soft cheese product (like the one below), you can actually see for yourself how many grams of lactose it contains per serving.

  • For example, in Nancy’s Organic Whole Milk Cottage Cheese, the only ingredients are milk, cream, salt, and probiotic cultures.
    • If you look at the total sugar content, you’ll notice there are 3 grams of “sugar” and no added sugar per serving.  That natural sugar is actually milk sugar, aka lactose!

Generally speaking, I love Nancy’s dairy products – not just because they’re organic, but also because most of them happen to be fortified with probiotics (much like the ones in yogurt) which may help you to tolerate soft cheeses with more ease.

What about lactase enzymes?

Since a lactose intolerance links back to insufficient lactase enzyme production in the gut, many/most people with a lactose intolerance will find relief from taking a lactase enzyme supplement* right before consuming milk or other types of dairy containing lactose.

How to learn your lactose tolerance thresholds

If you need some more objective data to navigate your lactose tolerance thresholds, consider keeping a detailed IBS food diary (with supervision from a registered dietitian or holistic nutritionist who specializes in gut health, as needed!).

OR – if you find you can’t even seem to tolerate the above lactose-free foods without feeling sick, read on – because you may actually have a dairy sensitivity.

Dairy sensitivity

There are many cases (anecdotally in clinical practice, AND in peer-reviewed studies) in which interventions like lactose-free diets and lactase enzyme supplementation are not providing any kind of sanctuary to IBS sufferers who want to enjoy dairy again. (10)

Usually, these are people who suffer from diarrhea-predominant IBS (IBS-D), mixed IBS (IBS-M), or inflammatory bowel disease (IBD).

Symptoms of dairy sensitivity

Not to mention, what about all the people who find that dairy triggers other types of symptoms like…

  • Headaches
  • Migraines
  • Fibromyalgia
  • Joint pain
  • Eczema
  • Psoriasis
  • Hives
  • Swelling / fluid retention
  • Autoimmunity
  • Lymphedema
  • Runny nose / rhinitis

That’s not in your head – chances are you have a food sensitivity to some or all types of dairy products.

(This is not all-or-nothing – some people can still tolerate certain types or constituents of dairy but not others!)


Food sensitivities are tricky to navigate, because unlike lactose intolerance, which takes place exclusively in the gut, a dairy sensitivity reaction is immune-mediated.


A dairy sensitivity reaction also isn’t limited to your gut – adverse reactions can occur systematically, since inflammatory chemical mediators will get released by white blood cells anywhere in your bloodstream when you eat a reactive food (in this case, certain types or all types of dairy).


Symptoms of a dairy sensitivity can also be delayed-onset (up to 72-96 hours after eating a reactive food), versus happening within an hour or two of consuming dairy.


Food sensitivity reactions can also be dose-dependent which means you may be able to tolerate dairy only in small quantities and not very often.

(People with a dairy sensitivity may also notice that it’s difficult to identify any kind of pattern through food logging: some days are fine, while other days are reactive.)

What about a dairy allergy?

In an allergic reaction to dairy, your mast cells are releasing histamine, since your body believes dairy food particles are invaders.

Some of the symptoms of a dairy allergy overlap with those of a dairy sensitivity (i.e. hives, vomiting, diarrhea), and people often get these two types of reactions confused.

The key differences are that your reaction will be pretty instant (within 30 minutes of eating dairy), and this mechanism involves only immunoglobulin E (“IgE”) antibodies within the mast cells of your immune system.

  • If you suspect you have an allergy to milk/dairy, you should consult with an allergist at a local allergy clinic.  They can run special types of allergy testing to figure this out.
    • If you’re having reactions to lactose-free dairy, and your allergy test comes back negative for dairy, it’s safe to assume you have dairy sensitivity vs lactose intolerance.

Learn more

Lactose intolerance vs dairy sensitivity: conclusions

Adverse food reactions aren’t black and white.  They exist on a spectrum.  This means you may or may not be able to tolerate certain types of dairy in moderation.

While there’s a lot of overlap between lactose intolerance and dairy sensitivity (from a gastro-symptom standpoint), there are also some key differences.

Lactose intolerance takes place only in the gut, and it doesn’t involve the immune system.

A dairy sensitivity is an immune-mediated reaction that is different from an allergy.  These reactions can happen even when you’re eating lactose-free foods.

Unlike lactose intolerance, which is limited to your digestive system, a dairy sensitivity reaction is more broad and systemic.

  • For example, if you have a dairy sensitivity, eating certain types of dairy may triggers symptoms seemingly unrelated to your gut.  This could be chronic fatigue, depression, ADHD, pain, skin rashes/breakouts, fluid retention, or general inflammatory symptoms.

If you’re feeling unclear on the types of adverse food reactions you’re experiencing, consider working with a certified LEAP therapist.

Next steps

Wanna learn more about gut health and food sensitivities?  Join us in my free private Facebook group: Whole-istic Living for Better Gut Health!

Whole-istic Living ("Holistic Living") Facebook Group with Jenna Volpe

XO – Jenna

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