What does a FUT2 genotype mean for lifestyle?

The FUT2 gene determines secretor status. About 20 % of Europeans are non-secretors (homozygous for the inactive rs601338 variant). This affects gut microbiome composition, vitamin B12 absorption, and susceptibility to certain infections (e.g., norovirus). Evidence for B12 association is human-strong; for microbiome it is human-moderate. However, no robust trials show that dietary adjustments based solely on FUT2 genotype improve clinical outcomes. Practical advice: non-secretors may benefit from monitoring B12 levels, especially if vegan or with GI issues. Other lifestyle changes (e.g., specific probiotics) lack solid evidence. Any intervention should be guided by biomarkers and a physician, not genotype alone.