Why do some people enjoy the strong taste and smell of onions while others avoid them completely? Scientists believe that part of the answer lies in our genes.
New research from The University of Queensland suggests that the genes affecting our sense of taste and smell may also help explain why some people are more likely to develop certain diseases than others.
The study, published in the journal BMC Medicine, found that people who are genetically more likely to enjoy onions tend to have lower blood pressure and a lower risk of developing type 2 diabetes.
Although the research does not suggest that simply eating onions will automatically prevent disease, it provides an interesting clue about the complex relationship between food preferences and long-term health.
Poor diet is now one of the biggest health challenges in the world. Scientists estimate that unhealthy eating habits contribute to around 11 million premature deaths each year, mainly through heart disease and cancer.
Rates of obesity, type 2 diabetes, and cardiovascular disease are also increasing in younger adults, placing enormous pressure on healthcare systems around the world.
For decades, researchers have tried to understand which foods directly affect health and which foods are simply associated with better health.
This has proven extremely difficult. People who eat large amounts of vegetables, for example, may also exercise more, smoke less, and have higher incomes. These factors can make it difficult to determine whether a particular food is actually causing health benefits.
To tackle this problem, researchers led by Dr. Daniel Hwang at The University of Queensland’s Institute for Molecular Bioscience developed a new approach. Instead of only asking people what they eat, the team examined genes linked to taste and smell.
Taste and smell are among the main reasons people choose certain foods. Some people naturally prefer bitter foods, while others enjoy sweet foods or strong flavours. Because genes partly influence these preferences, scientists believe that studying taste and smell genes may provide a more reliable way of understanding how diet influences disease.
The researchers used information from the UK Biobank, one of the world’s largest health databases. They examined 325 genes related to taste and smell and looked at how these genes were associated with preferences for 140 different foods.
The study involved more than 160,000 adults between the ages of 37 and 73 years. The scientists then checked their findings in another group of participants from the Avon Longitudinal Study of Parents and Children, which included people around 25 years old. This second analysis helped confirm that the patterns found in the larger group were real and not simply due to chance.
The researchers also used a method called Mendelian randomization. This statistical approach takes advantage of natural genetic differences between people to help scientists determine whether one factor may actually cause another. The method has already been used successfully to study the effects of coffee, alcohol, and milk consumption on health.
The results showed that people whose genes made them more likely to enjoy onions tended to have lower blood pressure and a lower chance of developing type 2 diabetes. The findings suggest that taste and smell genes may become valuable tools for understanding how diet contributes to disease.
The researchers believe their framework offers a quicker and less expensive way to strengthen evidence about food and health relationships. It may help scientists better distinguish between foods that truly affect health and foods that simply happen to be linked with healthier lifestyles.
The findings should still be interpreted carefully. The study does not prove that onions are a miracle food or that eating large amounts of onions will protect someone from disease. Diet is extremely complex, and many factors, including exercise, sleep, income, education, and access to healthcare, also influence health outcomes.
Even so, this study represents an important advance in nutrition research. By focusing on genes that shape our senses of taste and smell, scientists have developed a creative new way to investigate one of medicine’s most challenging questions: how the foods we prefer may affect our long-term health.
The approach could eventually help researchers identify dietary patterns that genuinely reduce the risk of major diseases and support more personalized nutrition advice in the future.
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Source: The University of Queensland.
