Food intolerance
In plain language
Many people experience stomach pain, a bloated feeling or fatigue after eating. Often this is dismissed as a ‘sensitive gut’ or stress, when in fact a food intolerance may be involved. Important: an intolerance is not an allergy. An allergy is a direct immune reaction; an intolerance is subtler — you lack the enzymes or bacteria to digest something properly. With lactose, for example, your predisposition determines whether you produce the enzyme lactase, but your microbiome can take over part of the digestion. That is why a DNA test alone never tells the whole story. The same applies to fructose and histamine intolerance: each time, enzymes, transporters and gut flora work together. Those who know the real cause understand why they react differently from someone else — and can adjust in a targeted way instead of cutting things out blindly.
The science behind
Intolerances arise where enzyme capacity and microbiome meet. In lactose intolerance, gene variants (backstage factors around the lactase gene) determine whether you keep producing the enzyme; if you produce little lactase, gut bacteria such as Bifidobacterium and Lactobacillus can take over part of the breakdown and ease symptoms — or not, with a depleted microbiome. With fructose, a shortage of transporters or enzymes plays a role; with histamine, an imbalance in breakdown enzymes and microbial production. The Lancet Gastroenterology & Hepatology (2022) calls food intolerances one of the most underestimated causes of chronic gut complaints, often confused with irritable bowel.
That is why a single test falls short. A nutrigenetic reading shows predisposition (whether you produce enzymes readily or slowly), a microbiome analysis shows whether beneficial bacteria compensate or are precisely missing, and metabolites reveal what is actually happening in digestion — which shortfalls or build-ups are feeding symptoms. Springer Nutrition Reviews (2022) states that only the combination of DNA, microbiome and metabolites gives a complete picture of digestive problems.
The connecting logic is co-metabolism: whether an intolerance stays mild or produces symptoms depends on the interplay between predisposition, gut flora, metabolites and lifestyle. In this way the question shifts from ‘what do I cut out?’ to ‘why do I react this way, and what supports my digestion?’. This reading is supportive and observational — not a medical diagnosis.
Illustration & CosmoTalks
From insight to daily practice — five episodes on measuring, understanding and acting.
- S12·E1 — From a single test to the whole story
- S12·E2 — Multi-omics: the film instead of the photo
- S12·E3 — Why the same advice does not work for everyone
- S12·E4 — Measure, understand, adjust
- S12·E5 — Prevention as a lifestyle
Related concepts
Discover more in the Cosmogroup ecosystem
From knowledge to application — choose your next step.
My InnerSelfie
Discover the real cause of your symptoms: DNA, microbiome and metabolites together, instead of cutting things out blindly.
Discover My InnerSelfie →My Key Nutrients
Support your digestion in a targeted way: pre- and probiotic strategies that help buffer intolerances.
View the range →CosmoPulse
For wellbeing and resilience: digestive signals translated into practical choices.
Discover CosmoPulse →The books · HOST · FORMULA · EDGE
The common thread of this science, from insight to daily application, by Petra Van Gucht.
See the books →Scientific references
• Springer Nutrition Reviews (2022) — Multi-omics for a complete picture of digestive problems.
• Nature Reviews Gastroenterology & Hepatology (2021) — Microbial metabolism of dietary carbohydrates.
• Van Gucht P. — HOST (COSMO trilogy): why your reaction to food is unique.
Frequently asked questions
- What is the difference between an intolerance and an allergy?
- An allergy is a direct, sometimes life-threatening immune reaction; an intolerance is subtler — you lack the enzymes or bacteria to process something properly.
- Why is a DNA test not enough?
- Because your microbiome can take over part of the digestion or make it worse. Only DNA, microbiome and metabolites together give the complete picture.
- Can my gut flora ease symptoms?
- Yes — with lactose, for example, beneficial bacteria take over part of the breakdown. With a depleted microbiome, symptoms actually get worse.
- Do I have to cut out foods for good?
- Not necessarily. By knowing the cause you can support and buffer in a targeted way instead of cutting things out blindly. This is supportive, not a diagnosis.
Captivated by co-metabolism?
You have just read one piece of the puzzle. There is a path for the curious who want to understand themselves better — and a deeper library for the professional who works with it.
Discover your own story
Curious what co-metabolism means for you? Discover what your own body is trying to tell you every day — and stay up to date with new insights.
Discover your analysis →Join us and get access
Become an affiliated healthcare professional and unlock the depth we reserve for our partners: the books to read online, the Well@Work and Sport experiences, the protocols and a network of like-minded people.
Join us →