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28 Apr 2023

Tears of joy

Food & Fluids

When it comes to flavour and health benefits, the humble onion delivers the goods.

Onions are highly nutritious and have been associated with several benefits, including improved heart health, better blood sugar control, and increased bone density.

Though all vegetables are important for health, certain varieties offer unique benefits.

Onions are members of the Allium genus of flowering plants that also includes garlic, shallots, leeks, and chives.

These vegetables contain various vitamins, minerals, and potent plant compounds that have been shown to promote health in many ways.

In fact, the medicinal properties of onions have been recognized since ancient times, when they were used to treat ailments like headaches, heart disease, and mouth sores.

There are specific areas where onions make other vegetables weep with envy.

1. Nutritious
Onions are nutrient-dense, meaning they’re low in calories but high in vitamins and minerals.

One medium onion has just 44 calories but delivers a considerable dose of vitamins, minerals, and fibre.

This vegetable is particularly high in vitamin C, a nutrient involved in regulating immune health, collagen production for tissue repair, and iron absorption.

Vitamin C also acts as a powerful antioxidant in your body, protecting your cells against damage caused by unstable molecules called free radicals.

Onions are also rich in B vitamins, including folate and vitamin B6 — which play key roles in metabolism, red blood cell production, and nerve function.

Lastly, they’re a good source of potassium, a mineral which many people are lacking.

2. Heart health
Onions contain antioxidants and compounds that fight inflammation, decrease triglycerides, and reduce cholesterol levels — all of which may lower heart disease risk.

Their potent anti-inflammatory properties may also help reduce high blood pressure and protect against blood clots.

Quercetin is a flavonoid antioxidant that’s highly concentrated in onions. Since it’s a potent anti-inflammatory, it may help decrease heart disease risk factors, such as high blood pressure.

Onions have also been shown to decrease cholesterol levels.

3. Rich in antioxidants
Antioxidants are compounds that inhibit oxidation, a process that leads to cellular damage and contributes to diseases like cancer, diabetes, and heart disease.

Onions are an excellent source of antioxidants. In fact, they contain at least 17 different varieties of flavonoid antioxidants.

Red onions, in particular, contain anthocyanins, which are plant pigments in the flavonoid family that give red onions their deep colour.

Multiple population studies have found that people who consume more foods rich in anthocyanins have a reduced risk of heart disease.

A study showed that habitual intakes as high as 613 mg per day of anthocyanins were correlated to a 14% lower risk of nonfatal heart attacks

Similarly, a 2018 review concluded that consuming higher amounts of anthocyanin-rich foods was associated with a lower risk of heart disease and heart disease mortality.

4. Anti-cancer compounds
Eating vegetables of the Allium genus like garlic and onions has been linked to a lower risk of certain types of cancer, including stomach and colorectal cancer.

A review of 26 studies showed that people who consumed the highest amount of allium vegetables were 22% less likely to be diagnosed with stomach cancer than those who consumed the lowest amount.

These cancer-fighting properties have been linked to the sulphur compounds and flavonoid antioxidants found in allium vegetables.

5. Blood sugar control
Eating onions may help control blood sugar, which is especially significant for people with diabetes or prediabetes.

A study of 42 people with type 2 diabetes demonstrated that eating 3.5 ounces or 100 grams, of raw red onion significantly reduced fasting blood sugar levels after 4 hours.

Additionally, multiple animal studies have shown that onion consumption may benefit blood sugar control.

Specific compounds found in onions, such as quercetin and sulphur compounds, also possess antidiabetic effects. For example, quercetin has been shown to interact with cells in the small intestine, pancreas, skeletal muscle, fat tissue, and liver to control whole-body blood sugar regulation.

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Date Published: March 2023

To be reviewed: March 2026