Why Can't I Digest Dairy? The Role of the LCT & MCM6 Genes + A Guide to Personalised Nutrition

DNA Testing
Gut Health
Why Can't I Digest Dairy? The Role of the LCT & MCM6 Genes + A Guide to Personalised Nutrition


  1. Introduction
  2. The science behind Lactose Intolerance
  3. Role of Lactase Enzyme
  4. Symptoms
  5. Genetic Factors
  6. DNA Testing
  7. Personalised Nutrition
  8. Conclusion

In 30 seconds... Ever puzzled over why a scoop of ice cream turns your stomach into a battlefield, while others relish it with zero issues? Your DNA holds the key. Meet the LCT and MCM6 genes, the backstage managers of lactase production—the enzyme that helps you digest dairy. Some folks are genetically wired to enjoy dairy throughout their lives, while others experience bloating, gas, or even severe cramps. But there's good news! A simple genetic screening can reveal your dairy destiny, guiding you toward a personalized nutrition plan. Whether you're a dairy devotee or better off dairy-free, understanding your genetic makeup can be your ticket to digestive harmony.


You've just enjoyed a cheesy pizza or a creamy bowl of ice cream, and suddenly, your stomach revolts, giving you a stomach ache after eating cheese. Sound familiar? If so, you might be one of the millions of people worldwide who suffer from lactose intolerance or even dairy intolerance. But have you ever wondered why some people can happily devour dairy while others can't? The answer lies deep within your DNA, or as some genetic genie might say, in your gene decode. This blog aims to unravel the genetic mysteries behind lactose intolerance and how understanding your genes can lead to a personalised nutrition plan that could change your life.

The Science Behind Lactose Intolerance

What is Lactose Intolerance?

Lactose intolerance is far more than a trending topic or a convenient excuse to skip the cheese course. It's a genuine digestive issue that affects approximately 65% of the global population to some degree. The lactose intolerance symptoms can be mild discomfort like a little bloating or as severe as debilitating abdominal cramps and diarrhea. But what's the science behind these symptoms? Why do some people get to enjoy their dairy indulgence while others pay a painful price?

The answer lies in your digestive system. When you consume dairy products, your body needs to break down lactose, a type of sugar found in milk. For some people, this process goes off without a hitch. For others, it's like trying to solve a complex puzzle with missing pieces. The missing pieces, in this case, are the sufficient levels of an enzyme called lactase, which is crucial for breaking down lactose into simpler sugars—glucose and galactose—that your body can easily absorb. Without enough lactase, lactose ferments in the gut, leading to a host of uncomfortable symptoms.

The Role of the Lactase Enzyme

The lactase enzyme is like the unsung hero of your digestive system, quietly doing its job so you can enjoy your favorite dairy treats without any drama. Produced in the small intestine, lactase is responsible for breaking down lactose into simpler forms that your body can absorb. When there's a shortage of lactase, lactose remains undigested and moves into the colon, where it's fermented by bacteria. This fermentation process produces gases like methane and hydrogen, leading to bloating, gas, and other digestive discomforts.

But why do some people have a lactase abundance, while others face a lactase deficiency? The answer is in your genes. Your genetic makeup plays a significant role in determining the levels of lactase your body produces. Some people are genetically predisposed to produce lactase throughout their lives, while others see a sharp decline in lactase production as they age, particularly after weaning. This genetic predisposition is what sets the stage for whether you can enjoy a cheese platter or ice cream sundae without any repercussions.

Symptoms of Lactose Intolerance

When it comes to lactose intolerance, the symptoms can vary widely from person to person, depending on the severity of their condition and the amount of lactose consumed. However, there are some common signs of lactose intolerance in adults that you might be dealing with lactose intolerance:

Gastrointestinal Symptoms

  1. Bloating: One of the most common symptoms, bloating occurs when undigested lactose ferments in the colon, producing gas.
  2. Diarrhea: The undigested lactose draws water into the intestines, which can lead to loose, watery stools.
  3. Abdominal Pain: This can range from mild discomfort to severe cramps, often exacerbated by the gas produced during lactose fermentation.
  4. Gas: The fermentation of lactose in the colon produces gases like methane and hydrogen, leading to flatulence.
  5. Nausea: Some people may feel nauseous after consuming dairy, although this is less common.

Systemic Symptoms

  1. Fatigue: The body's struggle to process lactose can sometimes lead to feelings of tiredness or fatigue.
  2. Headache: Though less common, some people report experiencing headaches after consuming lactose.

Timing is Everything

These symptoms & signs of dairy intolerance in adults usually appear within 30 minutes to 2 hours after consuming foods or drinks that contain lactose. The timing can offer a clue: if you experience these symptoms shortly after a dairy-heavy meal, lactose intolerance could be the culprit.

Severity and Individual Differences

It's important to note that the severity of symptoms can vary widely among individuals. Some people can tolerate a small amount of lactose, while others experience symptoms even with minimal exposure. Factors like your genetic makeup and the presence of other digestive issues can also influence the severity of your symptoms.

The Genetic Factors

The LCT Gene: The Mastermind Behind Lactase Production

Imagine your body as a grand theatre, and the LCT gene as the director orchestrating the entire show of lactose digestion. This gene is responsible for the production of lactase, the enzyme that breaks down lactose. But not all directors—or genes—are created equal. A specific variation in the LCT gene, known as the LCT-13910C>T polymorphism, can make a world of difference in how your body handles lactose.

If you carry the "T" allele of this polymorphism, you're in luck! Your body continues to produce lactase into adulthood, allowing you to enjoy dairy products without any issues. On the flip side, those with the "C" allele often experience a decrease in lactase production after childhood, making dairy consumption a risky affair. So, before you indulge in that tempting cheese platter or creamy dessert, it might be worth finding out which version of the LCT gene you carry.

The MCM6 Gene: The Unsung Hero

While the LCT gene takes most of the limelight, there's another gene working behind the scenes that deserves some attention: the MCM6 gene. Located near the LCT gene, MCM6 acts like the assistant director, influencing how the LCT gene behaves. It contains regulatory elements that control the expression of the LCT gene, essentially determining how much lactase your body produces.

Specific variations in the MCM6 gene can either boost or hinder lactase production. So, even if your LCT gene is set for high lactase production, a conflicting MCM6 gene could throw a wrench in the works. It's like having a director and assistant director with different visions for the same movie—something's got to give.

Other Contributing Genes

While the LCT and MCM6 genes are the stars of the show, they're supported by a cast of other genes that can also influence lactose digestion. One such gene is the MTHFR gene, which plays a role in various metabolic processes, including the breakdown of certain sugars and amino acids. Variations in the MTHFR gene could potentially affect how efficiently your body processes lactose, adding another layer of complexity to the lactose intolerance narrative.

Testing for Lactose Intolerance

Traditional Methods

Traditionally, lactose intolerance is diagnosed through breath tests or even trial-and-error elimination diets. However, these methods can be time-consuming and uncomfortable.

The Power of Genetic Screening

Enter genetic screening,  a revolutionary way to get to the root of your digestive issues. While there isn't a specific lactose intolerance test or dairy intolerance test it is often included in DNA health tests. With just a simple test from a reputable DNA company, you can uncover your genetic predisposition to lactose intolerance, allowing for more personalised and accurate lactose intolerance treatments.

A Guide to Personalised Nutrition

Why Personalised Nutrition?

Imagine a world where every meal you eat is designed specifically for you, taking into account your unique genetic makeup. No more guesswork, no more one-size-fits-all diet plans, and no more slogging through diets that don't seem to work. Welcome to the world of personalised nutrition—a revolutionary approach that could be the key to unlocking your optimal health and well-being.

By understanding your genetic predispositions, you can make more informed choices about your diet and lifestyle. For instance, if you're genetically predisposed to lactose intolerance, you can adjust your diet to include lactose-free or low-lactose options. But it's not just about avoiding certain foods; it's about optimizing your entire diet to suit your genetic profile. This could mean incorporating specific nutrients that you metabolize well or avoiding certain food types that you don't. The possibilities are endless, and the benefits are immense, from improved digestive health to enhanced mental well-being.

Keywords: personalised nutrition plans, personalised diet, personalised health

How to Create Your Personalised Nutrition Plan

Creating a personalised nutrition plan might sound like a task for experts, but it's actually quite straightforward. The first step is to get a comprehensive DNA + Epigenetic Health Test. This test will provide you with a wealth of information about your genetic predispositions, including how your body processes different types of foods, nutrients, and even how you respond to various forms of exercise.

Once you have your test results, the next step is to consult with a healthcare provider who specializes in genetics and nutrition. They can help interpret your results and guide you in creating a nutrition plan that's tailored just for you. This could involve specific recommendations on types of foods to eat, portion sizes, and even meal timing. The goal is to create a plan that not only helps you manage symptoms of lactose intolerance but also optimizes your overall health based on your genetic makeup.


So, the next time you find yourself questioning your dairy choices, remember that the answer could lie in your genes. Understanding the role of the LCT and MCM6 genes in lactose intolerance can open the door to a world of personalised health and nutrition. Ready to take the first step? Consider getting a genetic screening test today and unlock the secrets to a happier, healthier you.