New Research Shows This Common Pantry Staple May Lower Your Risk of Diabetes and High Blood Pressure
Can an onion a day really help keep certain health hazards at bay? A nutritionist explains.
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If you love the smell and taste of freshly sliced onions, you may be more likely to have both lower blood pressure and a lower risk of type 2 diabetes. In a recently published study, researchers used genetic factors like taste and smell to better understand the link between diet and chronic disease. To find out what this research showed, and learn if you should be adding onions to your daily diet, keep reading.
"Correlation" Versus "Causation"
Before we get into the actual study, here’s a little explainer, because, simply put: nutrition research is complicated! There is extensive observational evidence that links certain dietary factors with chronic disease, which is deemed "correlation" as opposed to "causation." "Correlation" means that two factors (the food and the disease marker, for example) change together — when one goes up or down, the other also goes up or down. However, "causation" means that one event actually made the other event happen (for example, eating one food causes you to have low blood pressure). As of now, nutrition research is based on correlation as there are many external factors scientists can’t account for. However, when decades of research point to the same results, a strong correlation can be built.
Okay, now back to those onions and the research…
The Research
Researchers at the University of Queensland’s Institute for Molecular Bioscience looked at taste and smell genes to help determine if specific foods cause disease. Researchers looked at the smell and taste preferences of 140 foods in over 160,000 adults between the ages of 37 to 73. The findings were assessed against a younger population of 25-year olds from the Avon Longitudinal Study of Parents and Children to confirm that they had the same genetic patterns as the older group.
When all 140 foods were tested among the older and younger subjects, researchers found that only onions checked all their boxes. The researchers concluded that people with a genetic disposition of liking the taste and smell of onions was associated with a lower systolic and diastolic blood pressure and reduced risk of type 2 diabetes. However, there was no evidence that liking onions affected body mass index, blood sugar levels, or blood fat levels (like triglycerides).
Researchers used a statistical approach called Mendelian Randomization, which uses genetic differences between individuals to assist scientists in separating causation from correlation in health research. Typically, nutrition research uses self-reported food intake, which isn’t the most reliable method. Using genetics helps better control the experiment, which is typically difficult to do in traditional nutrition research. But, Mendelian Randomization has its drawbacks as it’s difficult to determine valid genetic markers that reliably reflect what people consume. As such, more research is needed on the effects of onions on chronic disease.
Should You Be Eating More Onions?
Although the findings above leave some unanswered questions, consuming onions as a regular part of a healthy eating plan is easy to do, as they are the foundation to many dishes. Plus, onions are easily accessible and affordable. You can slice them into sandwiches or salads, or chop and sauté them into a mirepoix (a combo of carrots, onions, and celery) to use them as a base for soups, and many other dishes.
The DASH (Dietary Approaches to Stop Hypertension) Diet, commonly recommended to help reduce and control blood pressure, suggests eating plenty of fruits and vegetables, including onions. "There is an abundance of science to support the heart health benefits of the DASH diet," says Dana Angelo White, culinary dietitian and author of DASH Diet Meal Prep for Beginners. "DASH also offers a holistic approach to eating that isn’t overly restrictive, so you can stick to it long term."
In addition, in my Create-Your-Plate Diabetes Meal Prep Cookbook, I recommend that people with diabetes use the diabetes plate method, which encourages filling half your plate with low-carb vegetables, including onions (which can be cooked alongside other low-carb vegetables, like mushrooms, kale, tomatoes, pepper, and more!).
Bottom Line: Onions are delicious, easy to use, and add flavor to a wide array of dishes. They can be a healthy part of any well-balanced diet, including for people who have high blood pressure and those living with diabetes.
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