Is FUT2 destiny or just a small risk factor?

FUT2 is not destiny but a small risk factor. The gene determines secretor status: about 20 % of people (non-secretors) carry an inactive variant (e.g., rs601338). Non-secretors have a slightly increased risk for recurrent urinary tract infections, Crohn’s disease, and lower vitamin B12 levels. At the same time, they are better protected against norovirus infection. However, effect sizes are modest – most conditions are polygenic and environmentally influenced. A single FUT2 SNP explains only a small fraction of risk. Evidence comes from GWAS and epidemiological studies, not from randomized trials. Therefore, overinterpreting the result is not warranted. Practically, one might monitor B12 levels, but a general lifestyle change is not indicated.