Can Eating Onions Really Help Lower Your Blood Sugar?

When you're trying to manage your blood sugar, it's a good idea to fit more non-starchy vegetables into your diet because they're low in both calories and carbohydrates.

But can vegetables like onions actually help regulate your blood sugar levels? Do onions, in particular, have any other health benefits for people with diabetes?

Here, learn how you can eat onions to lower blood sugar, and other onion benefits.

Before diving into the effect of onions on blood sugar, it helps to know a bit about their nutrient content.

Onions are low in calories and a good source of fiber and vitamin C. Here's a breakdown of their nutrients, per the USDA:

If you're looking for ways to lower blood sugar, incorporating more low-carb veggies like onions into your diet may help. Onions have a low glycemic index, which may be helpful for people with diabetes, per the Mayo Clinic. Examples of other low-GI vegetables include leafy greens, raw carrots, kidney beans, chickpeas and lentils.

While there isn't much current research surrounding blood sugar-regulation and onions, there are a few older studies that draw some possible links between the two.

In particular, one older October 2014 review in ‌Nutrition‌ mentions sulfur compounds found in onions, (namely S-methylcysteine and the flavonoid quercetin) may be responsible for the vegetable's effect on blood sugar.

The review also mentions that, in clinical trials, people with diabetes experienced blood sugar-lowering effects after eating onion slices.

An even older October 2010 study in ‌Environmental Health Insights‌ found people with diabetes who ate raw red onion had lower fasting blood sugar levels 4 hours later.

Keep in mind, though, that more research is needed in order to determine these connections. Always talk to your doctor before trying at-home remedies to regulate blood sugar.

Besides possibly helping with blood sugar, there are some other health benefits of onions that are worth noting. These include:

Onions are full of nutritious antioxidants and vitamins that can help reduce levels of inflammation throughout the body. Per the Cleveland Clinic, they contain about 25 different flavonoids, a type of antioxidant that's helpful in warding off disease.

One flavonoid, called quercetin, offers heart-healthy benefits and can help fight obesity and metabolic syndrome, along with high blood pressure and cholesterol, per the Cleveland Clinic.

Red onions, in particular, have health benefits because of their anthocyanin content. Anthocyanins are antioxidants that give red onions their purple-reddish color. So when you're cooking with red onions, try to keep as much of the vegetable with the coloring as possible to reap the benefits, per the Cleveland Clinic.

While onions can be a trigger for people with irritable bowel syndrome (IBS) — causing gas, bloating and occasional diarrhea — they can be beneficial in other instances due to their prebiotic content, per UMass Chan Medical School.

Onions contain sulfur, which may not be great in regards to body odor but can be beneficial for digestive and overall health, per Mount Sinai.

Prebiotics serve as food for the "good" bacteria in your gut, helping them to grow and thrive, per the Mayo Clinic.

Onions are a sufficient source of prebiotics and fiber, but they may be better digested and offer more benefits for your digestive system when cooked, per the Cleveland Clinic.

Eating onions could be part of a healthy diet that helps reduce your risk of certain cancers. A small October 2019 study in ‌Asia-Pacific Journal of Oncology‌ found eating allium vegetables (i.e., onions) is associated with a reduced risk of colorectal cancer.

And according to the Cleveland Clinic, eating a diet rich in onions may also help reduce your risk of other cancers, including bladder cancer and stomach cancer.

Keep in mind, though, that this does ‌not‌ mean eating onions alone will prevent or cure cancer.

Especially for older adults, eating onions or drinking onion tea may help support bone health, per the Cleveland Clinic.

One February 2016 study in ‌Food & Function‌ found middle-age and postmenopausal people who drank 3 ounces of onion juice every day for eight weeks had mildly improved bone mineral density. The study authors conclude drinking onion juice could help treat bone-related disorders like osteoporosis.

If you want to reap onion water benefits or onion tea benefits, try making it yourself.

While the research is not solid on whether onions can lower your blood sugar, they are a low-calorie, low-glycemic, non-starchy food, which may be helpful for people with diabetes.

A few ways to incorporate onions into your diet include:

• Slicing raw onions to add to sandwiches or salads
• Grilling or roasting onion slices to add to a meal
• Dicing or sautéeing them with peppers as a side dish or topping
• Turning them into a relish
• Pack more onions into existing recipes — especially for soups, chilis and stews — to add more volume (and fiber) without much increase in carbs or calories
  

There are many different things you can do at home to manage high blood sugar, per the Centers for Disease Control and Prevention (CDC):

• Get regular exercise
• Take your medicine as instructed
• Follow your diabetes meal plan, prioritizing fruits and veggies along with foods lower in calories, saturated fat, trans fat, sugar and salt (see your doctor or a registered dietitian if you need more guidance)
• Stick to a regular eating schedule and don't skip meals
• Limit alcohol
• Check your blood sugar as directed by your doctor, and take note of what makes your levels go up or down
• Talk to your doctor about adjusting your insulin dose

While there isn't a lot of research into the role of onions in regulating blood sugar, they are a low-glycemic food and contain sulfur compounds, which could have a blood sugar-lowering effect.

On top of that, onions contain healthy antioxidants that are linked to a lower risk of disease.

If you're unsure about whether you should incorporate onions into your diet to help manage your blood sugar, talk to your doctor or a registered dietitian. They can help you come up with a diabetes diet plan and suggest other blood sugar-regulating foods.