Hello friends! I hope you’re having a wonderful day. I apologize for the blip in blogging; I have been crazy busy with school and experiencing simultaneous computer issues. I am really hoping my laptop holds out for service until winter break. I really need it! Eep! Anyways, today while studying for a test, I was reviewing lactose intolerance and thought “Gee, this is interesting. Maybe I can procrastinate studying by writing a blog post about what causes lactose intolerance.”

So here we are! Procrastinating studying by writing about something else I’m studying. Do I know how to have a good time or what? But all jokes aside – this is a topic that impacts the majority of people (yup, more people are lactose intolerant than tolerant – read on to find out why).
I grew up super duper lactose intolerant, and that was back in the day before there was a dairy-free version of everything (I remember kids making fun of my Silk Very Vanilla boxes of soy milk, which by the way, are still delicious). Luckily, lactose intolerance is easy for most to manage, especially nowadays thanks to the dairy-free boom. But let’s chat about what lactose intolerance actually is, and why it happens. Read on!
What is lactose intolerance?

Lactose intolerance is the inability to digest lactose, which is the main sugar found in milk. Lactase, an enzyme, breaks lactose into glucose and galactose, to be absorbed by your small intestine.
People with lactose intolerance have insufficient lactase, meaning lactose in milk can’t properly be split into glucose and galactose for easier absorption.
Instead, individuals who are lactose intolerant have undigested lactose in their colon. Bacteria flock to the lactose to try to break it down. This fermentation process causes osmosis (meaning it brings water to the area) and creates gas, which comes out as, well, gas. The bacterial breakdown of lactose leads to the symptoms associated with lactose intolerance.
What are the symptoms of lactose intolerance?

Bloating, diarrhea, gas, abdominal pain, nausea, stomach rumbling/gurgling sounds, and indigestion upon ingestion of milk or milk products.
Some people may even vomit upon ingestion of lactose-foods.
What causes lactose intolerance in humans?

As it turns out, lactase deficiency is actually the norm for most adult populations. In most mammals (including humans), the gene that transcribes for lactase to be produced is turned off as the mammal matures after weaning off milk from their mothers, limiting their ability to digest milk after childhood.
If you think about it, since most species do not consume milk after early life, turning off the gene that transcribes the enzyme needed to break down milk sugars makes sense. So actually, it seems, lactose intolerance is the norm.
Lactose tolerant people have a Single Nucleotide Polymorphism (SNP) in their DNA that allows them to continue to transcribe for the continued production of the lactase enzyme beyond younger years.
This is called a gain-of-function SNP, because the mutation in the DNA allows for the gaining of function of DNA.
The SNP that leads to lactose tolerance is found more commonly among certain populations than others.
The regions where the gain-of-function SNP are highest tend to overlap with historically nomadic regions, like Northern Europe.
Other regions, like Asia, tend to have less of the gain-of-function SNP, and thus, greater levels of lactose intolerance.
How can I manage lactose intolerance?

Lactose intolerance is primarily managed through diet. If you suffer from lactose intolerance, avoid consuming large portions of foods that cause symptoms, such as milk and milk products, like yogurt.
Be sure to carefully read the labels of food products, as many ingredients that are milk-based (including whey, cream, milk solids, casein, etc) that do not directly appear as the word “milk” on the back of the package. Since milk is an allergen, if a product contains milk, it should scream CONTAINS MILK somewhere immediately after the ingredient list.
If you want to consume milk products, try to have smaller portions, and/or take a lactase enzyme pill prior to consumption.
You can also enjoy non-dairy versions of pretty much all dairy products these days, thanks to the plant-based movement (it is so much easier now compared to when I was growing up a lactose intolerant kid)!
Take Home:

Lactose intolerance is very common, and can be very uncomfortable. Lactose tolerance is actually a result of a SNP that allows continued transcription of a gene that produces the lactase enzyme beyond young childhood, which helps your body breakdown milk. Lactose intolerance can be treated via dietary avoidance of triggering foods in large amounts, and/or swapping dairy foods for dairy-free versions.
That’s all for now! I have a post on coconut oil coming later this week and I hope to push out a few videos next weekend. Thanks as always for sticking around, and as always, feel free to reach out to me with questions, comments, thoughts, concerns, or emotions by leaving a comment below, or connect with me on Instagram, Twitter, or YouTube!
Remember, Millie loves you!
You may also like:
- What are Ultra-Processed Foods? How do Ultra-processed foods impact health?
- How to Replace an Egg in Any Recipe
- Nutrition for Vegans: What to know if you’re on a plant-based diet
- Easy Vegan Chocolate Pudding
Leave a Reply