Episode 124 – Lactose Intolerance

Key Topics Covered

Dairy foods.


  •  Approximately 65% of the world’s population are to some degree lactose intolerant.
  • Although this seems very high, it’s not unrealistic. Even if you went with a different number from another source, the prevalence is still high.
  • There are also varying degrees of intolerance. Somebody who is very mildly lactose intolerant likely isn’t going to identify themselves as lactose intolerant. But technically they fit within that 65% number.
  • A lot of people also don’t seem to want to identify as lactose intolerant for a variety of reasons.
  • Whilst severity can differ a lot, it appears that many of us have a sensitivity to lactose in some way shape or form.

Mechanism of Action

Lactose intolerance mechanism.

  • The main cause of lactose intolerance is having an insufficient amount of the lactase enzyme. Usually, there is still some, just not enough. But in some cases, there are pretty much undetectable amounts.
  • Lactase is involved in digesting lactose in the small intestine.
  • We also have bacteria in the large intestine that can play a role in digesting lactose.
  • In those with enough lactase, the majority of lactose is digested in the small intestine and no issues occur.
  • In those lactose intolerant, there isn’t enough lactase to get the job done in the small intestine.
  • Then the lactose goes through the digestive tract into the large intestine and draws in water, which can lead to diarrhea.
  • The bacteria in the large intestine can feed on that lactose. But even that can cause issues since it can contribute to gas production, which can lead to gas and bloating.

The Importance of Understanding This

  • The reason why understanding these mechanisms is important is because it adds a bunch of clarification. Symptoms are NOT caused by an autoimmune response or anything like that. They are simply caused by undigested lactose.
  • This is why the dose is important. If you had a tiny amount of lactose, it physically can’t be causing major symptoms if it is lactose intolerance, even if you had no lactase at all.

Lactose Content in Products

Lactose Contents of Foods

  • Lactose content between dairy products varies a lot, this is why you get symptoms from some but not others.
  • Research indicates that often 12g of lactose in a sitting is fine without experiencing symptoms.
  • In practice, almost all people who identify as lactose intolerant will get symptoms from that though. 3g is probably more realistic.
  • YoPRO, Chobani FIT and Rokeby are low in lactose due to the lactase enzyme being added.

How to Test

  • While breath tests exist – they aren’t used as much anymore. This is largely just because whether or not you get symptoms matters more than if you technically don’t have enough of the lactase enzyme.
  • The way to test it is to simply have 1+ cups of lactose-containing milk one day. Then the next, have lactose-free milk. Feel free to repeat multiple times if needed to confirm. If you get symptoms from the lactose-containing one, but not the other, it is lactose intolerance. If you get symptoms from both, then it is likely something else.
  • Keep in mind you can have lactose intolerance AND other intolerances/issues.

Strategies to Improve Tolerance

Lacteeze Tablets


  • You can take the lactase enzyme before eating foods containing lactose.
  • Lacteeze is the main product in Australia.

Other Strategies

  • Eating lactose alongside other food helps.
  • Higher fat content helps too.
    • The reason for this is that it slows down how long it takes to go through the digestive tract, giving the body longer to process it.

Building/Retaining Tolerance

  • If you stop consuming lactose completely, often tolerance drops.
  • This is partly because the bacteria that feed on lactose die off.
  • You can build tolerance by having it frequently.
  • The issue here is that you can likely only build it so far. For example, if you previously had lactose regularly and it caused symptoms, then building up to having it regularly likely means you will still get symptoms.

Relevant Blogs / Resources

Blog Posts

Lactose Intolerance – How to Manage It


Lactose Intolerance Statistics

Mechanism & Dietary Management