More than 160,000 UK Biobank participants were analyzed in a BMC Medicine study that linked a genetic predisposition to liking onions with lower risks of type 2 diabetes and high blood pressure.
Researchers traced the pattern to a variant of the OR2T6 smell-receptor gene, using taste-and-smell genetics to probe whether food preferences can help explain diet-health relationships.
Experts said onions contain compounds such as quercetin, flavonoids and fiber and often appear in Mediterranean-style, nutrient-dense meals, though onion preference may also track with broader plant-based eating habits.
The study did not show that eating onions alone prevents either condition, and clinicians said onions should be viewed as one part of an overall healthy diet rather than a treatment.