Why Liking Onions May Be a Healthy Sign

You have probably heard that some people are genetically wired to dislike coriander. Now, new research suggests some people may be genetically predisposed to liking another common ingredient, and that preference may be linked with positive health markers.

The study, published in BMC Medicine, found that having a genetic predisposition to liking onions was linked with a lower risk of developing type 2 diabetes or high blood pressure.

Researchers analysed data from more than 160,000 adults aged 37 to 73 who took part in a long-running health study. The data included participants’ genetic information, including gene variants linked to food preferences, as well as their reported likes and dislikes for foods such as grapefruit, horseradish, wasabi, salt and onions.

After analysing the data, researchers found that people with a particular variant of the OR2T6 smell receptor gene were more likely to prefer onions. They then examined a range of health outcomes in people with that gene variant and found that a genetic preference for onions was linked with a lower risk of being diagnosed with high blood pressure and type 2 diabetes.

“One of the biggest challenges in nutrition research is figuring out whether a food actually affects health or whether it simply happens to be eaten by healthier people,” says lead study author and genetic epidemiologist Daniel Liang-Dar Hwang. “We wanted to develop a better way to answer that question. Because our sense of taste and smell plays a major role in the foods we choose to eat, we investigated whether genes that influence these senses could help us better understand the relationship between diet and health.”

The study does not prove that onions directly prevent high blood pressure or type 2 diabetes. It shows an association. Still, experts say there are a few possible reasons the link is worth exploring.

What’s behind the link?

There are likely a few things happening here.

Onions are vegetables, and they contain compounds that may support health, says registered dietitian Jessica Cording.

“Onions have a lot of really important compounds, including flavonoids, quercetin, and fiber,” she says. “These are beneficial for cardiovascular health.”

Onions also often show up in nutrient-dense meals, including dishes built around vegetables, legumes, wholegrains and lean proteins. They are commonly used in Mediterranean-style eating patterns, which are linked with better heart and metabolic health.

“They’re a big part of the Mediterranean diet, and often involved in healthier dishes,” Cording says, adding that eating healthier foods can help reduce the risk of developing type 2 diabetes.

It is also possible that people who like onions may be more likely to enjoy other plant-based foods, says endocrinologist Dr Richard Siegel.

“If they are more genetically likely to eat a plant-based, unprocessed diet, including onions, the foods may contain phytochemicals that may reduce the risk for high blood pressure and diabetes,” he says.

On the other hand, people who dislike onions may eat less of them and miss out on some of those plant compounds, says study co-author Danielle Reed.

“Not everyone can smell the flavor notes that make them yummy,” she says. “People who are blind to those flavors eat less onion and do not get the benefit.”

The practical takeaway is not that onions are a magic health food. It is that taste preferences can shape what people eat over time, and those small patterns may influence health. If you like onions, they can be an easy way to add flavour, fibre and plant compounds to everyday meals.

Will eating onions lower your blood pressure or type 2 diabetes risk?

Experts are not ready to say that yet.

“Our findings suggest that onion consumption may help lower blood pressure and reduce the risk of type 2 diabetes, but this study alone isn’t enough to recommend that people eat more onions specifically for these purposes,” Hwang says.

Cording agrees. No single food can meaningfully change disease risk on its own.

“I wouldn’t encourage people to think of onions as a treatment for high blood pressure or diabetes,” she says. “But I would think of them as a nutritious ingredient that can be part of an overall healthy eating pattern.”

That distinction matters. Onions may add fibre, flavour and beneficial plant compounds to meals. But they will not replace medication, blood pressure monitoring, diabetes care, regular movement, or a balanced eating pattern.

What’s the takeaway?

The bottom line is not that everyone suddenly needs to eat more onions. But if you already like them, there is no harm in using them more often in home cooking.

“For people with high blood pressure, it is worth trying to increase the consumption of onions and see if it has beneficial effects,” Reed says. “We are all experiments of one when it comes to nutrition.”

Just do not expect onions alone to change your numbers. Dr Siegel recommends staying active and following a healthy eating pattern, such as a Mediterranean-style or DASH-style diet, to support heart and metabolic health.

“You should never confuse association with causation, but if people want to eat onions, add them to anything you want,” Dr Siegel says.

Cording agrees.

“If you like onions, great,” she says. “But if you don’t like onions, you don’t have to force yourself to eat them. There are lots of vegetables that provide health benefits.”

In practical terms, onions can be an easy upgrade. Add them to soups, omelettes, salads, stir-fries, tray bakes, pasta sauces, curries, tacos, or roasted vegetable dishes. They bring flavour without needing much salt, which can be useful if you are watching blood pressure.

The best approach is still the broader one: eat more plants, choose mostly minimally processed foods, keep active and speak with your GP if you are concerned about blood pressure, blood sugar, or your personal risk.