Still bloated in 2025? It’s time to check your FUT2 Gene.
Do you have gas, bloating, constipation, diarrhea, or “food intolerances”?
If nothing’s worked for you yet, there may be a genetic component underlying your gut health that you probably didn’t know about.
The intestinal microbiome is a diverse array of microbes that colonize the human intestine. These bugs exhibit a symbiotic relationship with their host humans, as they serve to digest non-digestible food-based molecules, provide anti-inflammatory post-biotic molecules like butyrate, and induce cell-signaling pathways that are protective.
At current, we understand that there are about 1,000 species of bacteria inhabiting the human microbiome. Ideally, the microbiome is colonized predominantly by what we call “core” species, which include Firmicutes. Bacteriodetes, Actinobacteria and Verrucomicrobia.
When microbiome species become imbalanced and stray away from a core-dominant “enterotype,” often due to an environmental insult meeting a genomic vulnerability, we can see issues like irritable bowel syndrome, SIBO, and inflammatory bowel diseases like Crohn’s and Ulcerative Colitis.
Non-secretor status comes from a mutation in the FUT2 gene which leaves an individual unable to “secrete,” the blood type precursor antigen into their digestive mucus. This antigen serves an important prebiotic role for beneficial gut species.
Non-Secretors have been found to have lesser levels of Bifidobacterium, an important core species.
Additionally, non-secretors are more likely to develop intestinal permeability, which occurs when the tight junctions between intestinal cells loosen. This can result in IBS, SIBO, non-celiac gluten sensitivity, allergies, and in some cases, autoimmunity.
This genetic predisposition makes a compelling case for a rejection of the “one size fits all” gut health regimens we often see advertised.
Here in our office, when someone comes with GI concerns, I’ll do some combination of the following:
Order a microbiome test: I like the GI Map qPCR for GI complaints. This tests bacteria, viruses, and fungi, but also includes inflammatory markers like calprotectin, occult blood, and fecal fat and elastase to scan for absorption issues.
Order bloodwork: GI problems come hand in hand with nutritional deficiencies since our absorption is often compromised. I’ll check things like Vitamin D, iron, ferritin, homocysteine and methylmalonic acid, as well as basic blood parameters like a blood count and metabolic panel
Genomics: If you’ve have chronic longstanding GI problems since childhood, I’ll discuss analyzing your genetic blueprint to see if you have any genes contributing, including FUT2, and SI (sucrase isomaltase, a common gene mutation leading to sucrose intolerance, a condition often wrongly clumped into the SIBO camp)
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