News release

From: The University of Queensland

People who like the taste and smell of onions are more likely to have a lower risk of blood pressure and type 2 diabetes, researchers have found.

University of Queensland researchers have examined taste and smell genes to help determine whether specific foods cause or are linked to disease.

Dr Daniel Hwang, of UQ’s Institute for Molecular Bioscience, said his research team has established a new genetic framework to help scientists better understand how diet drives chronic disease.

“Determining if a specific food causes, or is linked to a disease, is a significant challenge in nutrition epidemiology,” Dr Hwang said.

“We have built a framework guided by taste and smell genes to help scientists better understand how diet contributes to chronic disease.

“Taste and smell are 2 major biological drivers influencing a person’s food choices and diet.

“By focusing on taste and smell genes, we created a new way for researchers to examine how diet influences disease.

“The aim is to help researchers cut through the complexity of distinguishing causation from correlation.”

Despite extensive observational evidence linking diet to chronic disease, strong causal evidence for specific foods, dietary patterns or nutrients remains limited, Dr Hwang said.

“Our research shows taste and smell genes are promising tools for studying links between diet and disease and can help strengthen evidence about cause and effect in nutrition research.

“This is important as we need better ways to understand how diet influences diseases such as diabetes, heart disease and cancer.”

Unhealthy diets cause an estimated 11 million premature deaths annually – primarily from cardiovascular disease and cancer – while rising rates of early onset obesity, cancer and diabetes have placed increased pressure on global healthcare systems.

Using data from the UK Biobank database, researchers developed the genetic framework after testing 325 taste and smell genes and their association with preferences and intake of 140 foods in more than 160,000 adults aged 37-73 years.

The findings were then assessed against a group of 25-year-olds from the Avon Longitudinal Study of Parents and Children to confirm the genetic patterns found in the previous group.

The researchers also combined the findings with a statistical approach known as Mendelian Randomization (MR), which uses genetic differences between people to help scientists distinguish cause from correlation in health research.

“MR nutrition research is expanding, with studies clarifying causal effects of coffee, alcohol and milk intake,” Dr Hwang said.

“Despite these advances, MR examinations of food and dietary patterns remain challenging due to difficulties in identifying valid genetic markers that reliably reflect what people eat.

Dr Hwang said the framework provided a quicker and more cost-effective way to strengthen evidence about cause and effect in nutrition research.

“Our framework gives scientists another way to study food and disease-related relationships without needing to undertake complicated experiments.”

Read the research published in BMC Medicine.