FUT2 Status
"Non-secretor" status changes how you absorb B12 and shapes your gut microbiome. This explains why some vegetarians stay healthy for decades while others crash within years—same diet, very different biology.
What this measures
How your DNA shapes FUT2 status.
FUT2 codes for an enzyme that builds specific sugar molecules onto the surface of cells lining the gut, saliva, and other body fluids. The "secretor" trait (active FUT2) places those sugars where gut bacteria can use them as food, shaping which microbes thrive. The "non-secretor" trait (FUT2 inactive) does the opposite.
Roughly 20% of people are non-secretors — carriers of two inactive FUT2 alleles (most commonly the W143X variant). Non-secretors are associated with higher circulating B12 levels (gut bacteria don’t consume as much), reduced susceptibility to certain norovirus strains, and different microbiome profiles than secretors. Neither is "better" — the two patterns produce different baselines.
Microbiome diversity differs between secretors and non-secretors, which influences fiber response, immune signaling, and inflammation. Prebiotic fibers feed different organisms in each group; one client’s "fiber works wonders" outcome may not transfer to a friend with the opposite FUT2 status.
The "I take the same B12 dose but my labs run higher than my partner’s" or "fermented foods agree with me differently" experiences often track to FUT2. Which version you carry changes how to read B12 results, how to support gut diversity, and which probiotic strains actually colonize.
FUT2 Status is one specific finding in this system. Your Genomic Lifestyle Optimization Report shows where your variants place you on the micronutrients and strategic supplementation spectrum — and what you can do about it: it renders as a dark card with a color marker calibrated to your variants, opening with the gene mechanism and closing with a practical, mechanism-led recommendation.
Want to see what a real Mosaic dark card looks like? Walk through a sample report →
In context
Water-Soluble Vitamins: the 8-insight cluster.
FUT2 Status is one finding in a tightly-related cluster. Mosaic sequences the other 7 alongside it so you see the whole biology — not an isolated data point.
Questions people ask
About FUT2 Status.
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