Onions are a staple in kitchens around the world, adding flavor and aroma to countless dishes. However, these everyday vegetables may offer nutritional benefits beyond their culinary uses. Researchers have been studying compounds found in onions, including quercetin and sulfur-containing substances, for their potential antioxidant, anti-inflammatory and antimicrobial properties.
Although the findings are promising, experts caution that research into these compounds does not mean onions can prevent or treat diseases on their own.
Onion Compounds and Their Potential Benefits
Onions contain quercetin, a plant flavonoid known for its antioxidant properties, along with sulfur-containing compounds that contribute to their distinctive smell and taste.
Laboratory and other scientific studies have investigated whether these substances may help protect cells from oxidative stress, influence inflammatory processes and affect the growth of certain microorganisms. However, the effects observed in experimental settings do not necessarily translate into proven health benefits in humans.
Including onions as part of a balanced diet can contribute to a varied intake of vegetables and plant-based nutrients.
What Research Says About Cancer Risk
Some studies have associated higher consumption of onions and related vegetables with a lower risk of colorectal cancer. These findings suggest a possible relationship between dietary patterns and cancer risk, but they do not establish that eating onions directly prevents the disease.
Cancer risk is influenced by multiple factors, including genetics, lifestyle, overall diet and environmental exposures. Onions should therefore be viewed as one component of a healthy eating pattern, rather than a substitute for recommended screening or medical care.
Onions and Blood Sugar: What We Know
Researchers have also explored onion extracts in studies involving blood sugar regulation, including research examining their use alongside diabetes medication.
These findings remain an area of investigation. Evidence involving concentrated extracts cannot automatically be applied to ordinary onions eaten as food, and onions should not replace prescribed diabetes treatment. Anyone considering onion supplements or extracts while taking medication should consult a healthcare professional.
Does a Cut Onion Become Toxic in the Refrigerator?
A common kitchen myth claims that a cut onion becomes toxic if it is stored for later use. This is not true. A properly handled and refrigerated cut onion does not become poisonous simply because it has been cut or stored.
Like other cut produce, however, onions can become unsafe if they are contaminated or kept at unsuitable temperatures. Store cut onions in a clean, covered container in the refrigerator and discard them if they show signs of spoilage.
How to Cut Onions Without Crying
Cutting onions releases compounds that can irritate the eyes and trigger tears. A few practical techniques may help reduce the discomfort:
- Chill the onion: Cooling it before cutting may slow the release of irritating compounds.
- Use a sharp knife: A sharp blade can reduce the crushing of onion tissue.
- Improve ventilation: Cutting near an extractor fan or in a well-ventilated area may help carry irritating vapours away from the eyes.
Cutting onions under water may also reduce exposure to irritating compounds, but it can be inconvenient and requires care when handling a knife.
Onions provide flavour, useful plant compounds and a simple way to add vegetables to everyday meals. Research into their potential antioxidant, anti-inflammatory and other effects continues, but stronger human evidence is needed before specific disease-prevention or treatment claims can be made.
For now, the best approach is to enjoy onions as part of a balanced diet, handle and store them safely, and rely on established medical advice for the prevention and treatment of health conditions.
