24 Jun Monell Center Finds Taste and Smell Genes Reveal How Onion Preference May Be Linked to Lower Blood Pressure and Type 2 Diabetes Risk
MedicalResearch.com Interview with:
Dr. Daniel Hwang
Dr. Daniel Liang-Dar Hwang
BSc, MBiotech, MSc, PhD
ARC DECRA Fellow
Institute for Molecular Bioscience
The University of Queensland
Brisbane, Australia
and Monell Chemical Senses Center
Philadelphia, PA, USA
MedicalResearch.com: What is the background for this study? What are the main findings?
Response: One of the biggest challenges in nutrition research is distinguishing causation from correlation. People who consume particular foods often differ in many other ways, such as income, education, physical activity, or overall health, making it difficult to determine whether a food itself influences disease risk.
Mendelian randomization has emerged as a powerful tool for investigating causal relationships by using genetic variants as proxies for exposures. However, finding genetic variants that reliably reflect what people eat remains a major challenge.
In this study, we developed a biologically informed framework for instrument selection using genetic variation in taste and smell receptor genes. Because taste and smell are major biological drivers of food choice, variants in these genes may provide biologically meaningful proxies for studying dietary exposures.
We examined more than 1,200 genetic variants in taste and smell receptor genes and tested their associations with preferences for 140 foods and beverages in more than 160,000 participants. We identified 700 significant gene–food associations, many of which were also linked to actual food intake and replicated in an independent cohort.
We then used these biologically informed variants in Mendelian randomization analyses to investigate potential causal relationships between diet and health, demonstrating how sensory genetics can be used to strengthen causal inference in nutrition research and identify foods that may influence disease risk.
MedicalResearch.com: What are some of the food preferences you identified as possibly being linked to better health parameters?
Response: The strongest example involved onion preference. We found that genetic variants linked to greater onion liking and consumption were associated with lower blood pressure and a lower risk of type 2 diabetes.
This finding was driven by a variant in the olfactory receptor gene OR2T6, which predicted onion liking in both older and younger adults and was also associated with onion consumption.
Importantly, the value of this finding extends beyond onions themselves. It illustrates how biologically informed genetic approaches can be used to generate stronger evidence regarding the potential health effects of specific foods.
We also identified robust genetic variants that can be used to study a range of other foods, including garlic, avocado, horseradish, and several dietary pattern-related traits, providing opportunities for future investigation.
MedicalResearch.com: What should readers take away from your report?
Response: The key message is that identifying the causal effects of diet on health remains a major challenge, and our study provides a new biologically informed approach to help address that problem.
Rather than relying solely on statistical associations, our framework focuses on genetic variation in taste and smell receptor genes, which help shape what people like to eat and what they actually consume. Because these genes are directly involved in food choice, they may provide more biologically meaningful tools for studying the health effects of specific foods. This, in turn, may strengthen Mendelian randomization analyses and improve our ability to determine whether particular foods genuinely influence disease risk.
More broadly, this work highlights the importance of integrating sensory science, genetics, and nutrition to improve our understanding of diet and health.
MedicalResearch.com: What recommendations do you have for future research as a result of this study?
Response: Future research should expand this framework to a wider range of foods, dietary patterns, and populations. Most large-scale dietary genetic studies have been conducted in individuals of European ancestry, and replication in more diverse populations will be important.
Beyond instrument development, our findings also highlight how much remains to be learned about the biology underlying food preferences.
We also see opportunities to map food molecules to the taste and smell receptors that detect them. A better understanding of these relationships could help refine biologically informed genetic instruments and improve our ability to investigate the health effects of specific foods and dietary components.
Ultimately, we hope that biologically informed approaches such as this will help prioritise dietary targets for clinical trials and contribute to a stronger evidence base for dietary guidelines and precision nutrition.
MedicalResearch.com: Is there anything else you would like to add? Any disclosures?
Response: This study was a highly interdisciplinary collaboration involving researchers from the University of Queensland, Monell Chemical Senses Center, the National Institutes of Health, QIMR Berghofer Medical Research Institute, and the University of Bristol.
We are also grateful to the participants and researchers involved in the UK Biobank and Avon Longitudinal Study of Parents and Children, whose contributions made this work possible.
The work was supported by funding from the Australian Research Council, the National Health and Medical Research Council of Australia, the National Institutes of Health, Monell Institutional Funds, and other supporting organisations listed in the manuscript.
The authors declare no competing interests beyond those disclosed in the published article.
For more on how diet and genetics intersect in disease prevention research, see MedicalResearch.com’s diabetes and metabolic health research coverage.
According to the National Institute of Diabetes and Digestive and Kidney Diseases, diet is one of the most important modifiable risk factors for type 2 diabetes, and ongoing research into how specific foods and genetic predispositions interact may help inform future prevention strategies.
Citation:
Hwang LD, Lin C, Evans DM, Martin NG, Reed DR, Joseph PV. Biologically informed instrument selection for dietary Mendelian randomization using chemosensory receptor variants. medRxiv [Preprint]. 2026 Feb 6:2026.02.05.26345702. Update in: BMC Med. 2026 Jun 1;24(1):359. doi: 10.64898/2026.02.05.26345702. PMID: 41674649; PMCID: PMC12889861.
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Last Updated on June 25, 2026 by Marie Benz MD FAAD