Onion-Loving Gene Linked to Lower Type 2 Diabetes and Blood Pressure Risk: Study

Scientists have identified genetic variants that may influence not only which foods people enjoy eating but also how those food preferences affect long-term health. A new study published in BMC Medicine found that a genetic variant associated with a stronger preference for onions was linked to lower blood pressure and a reduced risk of type 2 diabetes.

The international study used a genetic approach known as Mendelian randomization to better understand whether certain foods directly influence health outcomes. Unlike traditional nutrition studies, which can be influenced by lifestyle habits and inaccurate dietary reporting, Mendelian randomization uses naturally inherited genetic variants as proxies for food preferences. This allows researchers to investigate potential cause-and-effect relationships while minimizing bias.

The researchers analyzed genetic data from nearly 500,000 participants in the UK Biobank, examining more than 1,200 genetic variants across 325 taste and smell receptor genes. They identified 268 variants associated with preferences for 96 different foods, ranging from garlic and grapefruit to horseradish and onions.

After further validation, the team identified 25 robust genetic markers linked to 20 foods. One standout variant, found in the olfactory receptor gene OR2T6, was consistently associated with greater liking and consumption of onions across different populations.

People carrying this genetic variant had, on average, lower systolic and diastolic blood pressure and an approximately 14% lower risk of developing type 2 diabetes. The researchers found no association with body mass index, cholesterol levels, or blood sugar, suggesting the observed benefits were not simply due to an overall healthier lifestyle.

According to the researchers, onions contain compounds such as quercetin with known anti-inflammatory and cardiovascular properties, providing a plausible biological explanation for the findings. While the results strengthen evidence linking onion consumption to better cardiometabolic health, the researchers note that further studies are needed to confirm the findings and determine whether similar genetic approaches can help identify other foods that offer genuine health benefits.

REFERENCE: Hwang, L.-D., et al. (2026). A biologically informed framework for instrument selection in dietary Mendelian randomization using chemosensory genetics. BMC Medicine. DOI: 10.1186/s12916-026-04966-x. https://link.springer.com/article/10.1186/s12916-026-04966-x