1. Rich in Quercetin — A Powerful Antioxidant
Quercetin is a flavonoid found in high amounts in onions — especially yellow and red varieties.
What it may help with:
Reducing oxidative stress
Lowering inflammation markers
Supporting allergy relief (quercetin stabilizes mast cells)
Some lab and animal studies suggest quercetin might also support cardiovascular and brain health — though more human trials are needed.
Raw onions have more quercetin than cooked — but cooking still preserves significant levels.
2. Supports Heart Health
Heart disease is the leading cause of death worldwide — but diet plays a major role in prevention.
Onions contribute by:
Action
How It Helps
Mildly lowering blood pressure
Due to potassium and quercetin effects on vessels
Reducing LDL (“bad”) cholesterol oxidation
Slows plaque buildup in arteries
Improving circulation
Sulfur compounds may reduce clotting risk
Population studies link higher onion intake with lower rates of heart disease.