What Happens to Your Body When You Eat Onions Regularly

Besides adding flavor to your food, onions offer many health benefits. They contain plant compounds that may help with blood sugar control, heart health and immunity.

Onions contain antioxidant compounds, particularly the flavonoid quercetin, which may improve heart health. Research shows that quercetin can lower blood pressure, reduce cholesterol, and improve blood circulation.

In one study, people with mildly elevated cholesterol who drank 100 milliliters of onion juice saw a drop in total “bad” cholesterol and low-density lipoprotein (LDL).

Most research has been limited to small studies in humans or animals. Additionally, many studies use onion supplements instead of whole onions. More human research is needed.

Quercetin and sulfur compounds found in onions may help regulate blood sugar levels. They work by improving the way the body processes glucose (sugar) and responds to insulin.

A study of people with diabetes showed that eating 100 grams of raw red onion helped the body better use and remove sugar from the blood.

Onions, especially red onions, are a good source of vitamin C.

Vitamin C strengthens your immune system by supporting the production and function of white blood cells. In the body, white blood cells fight harmful bacteria and viruses that could cause infection or disease.

The sulfur compounds in onions may also support immune health. One study found that these compounds helped improve immune function in people with colorectal cancer.

An older study of perimenopausal and postmenopausal women found that eating onions may improve bone health. Women who ate onions at least once a day were up to 20% less likely to suffer a hip fracture than those who rarely or never ate them.

A 2024 study in rats with osteoporosis (weak, brittle bones) found that onion flavonoid extract helped improve bone strength and density. More human studies are needed to confirm the bone health benefits of onions.

Laboratory studies suggest that compounds in onions may help prevent the growth of harmful infection-causing bacteria. In one study, quercetin was shown to disrupt bacterial cell walls and prevent the growth of E.coli And Staphylococcus aureus.

Quercetin may also prevent the growth of Helicobacter pylori (H. pylori), a type of bacteria that infects the stomach. H. pylori may increase the risk of peptic ulcers and gastritis (inflammation of the stomach lining).

Onions are a natural source of prebiotics, which feed the good bacteria in your gut and promote digestive health. They contain inulin and fructooligosaccharides (FOS), fibers that promote a healthy gut microbiome. These fibers have also been linked to improved digestion, mood, nutrient absorption, and immune function.

The flavonoids and antioxidant compounds in onions can neutralize harmful free radicals before they damage your body’s cells.

Quercetin may prevent the formation of compounds that cause inflammation. These include leukotrienes, prostaglandins and histamines. This can help reduce inflammation associated with arthritis and other chronic illnesses. More human research is needed.

Quercetin and other flavonoids in onions may block the growth and spread of certain cancer cells.

A 2019 study found that regular consumption of allium vegetables, such as onions, leeks and garlic, can reduce the risk of colorectal cancer by up to 79%. Similarly, another study showed that higher consumption of garlic and onions could reduce the risk of breast cancer.

More well-designed human trials are needed to fully understand how onions can help prevent cancer.

When consumed in normal quantities, onions are generally considered safe for most people. However, there are a few things to consider:

• Gas and bloating: Onions are high in FODMAPs, which can cause digestive upset in people with irritable bowel syndrome (IBS).
• Allergic reactions: Although very rare, some people may be allergic to onions and have a reaction when handling or eating them. If you are allergic to other plants in the Liliaceae family, like garlic, you might also be allergic to onions.
• Drug interactions: In large quantities, onions can have an anticoagulant effect. If you are taking blood thinning medications, talk to your doctor before making any major changes to your diet.

Eating onions can also temporarily contribute to bad breath. You can manage bad breath by brushing your teeth, flossing, or using mouthwash after eating onions.

Onions can add depth and flavor to a variety of meals. Although raw onions offer health benefits, studies show that baked, grilled, or fried onions may increase their health-protective compounds.

Here are some easy ways to enjoy onions:

• Sauté onions in stir-fries and soups to enhance flavor
• Sprinkle finely chopped onions in salads and sandwiches
• Slowly caramelize onions for a sweet topping on burgers or grain bowls
• Roasted onions with other vegetables
• Add sliced ​​onions to tacos or avocado toast
• Mix onions into salad dressings, dips and sauces for added flavor

Onions are a versatile vegetable that can enhance the flavor of many dishes. They provide beneficial nutrients and compounds that can help improve your health. Although more human research is needed, regular consumption of onions as part of a balanced diet may support heart, bone, immune, and gut health.