Is raw or cooked onion better?

Both are valuable. Raw onion preserves more quercetin and vitamin C, while gentle cooking (steaming, sautéing) makes the flavor sweeter and easier on digestion. Heavy frying degrades antioxidants.

Are red onions healthier than yellow?

Red onions contain additional anthocyanin antioxidants in their purple skin, but yellow and white onions still deliver quercetin, inulin, and sulfur compounds. Variety is best.

Why do onions make us cry?

Cutting releases syn-propanethial-S-oxide, which irritates the eyes. Chilling onions 15 minutes before cutting, using a sharp knife, and cutting near running water reduce the effect.

Does onion really lower blood pressure?

Meta-analyses of quercetin (the main onion polyphenol) suggest modest reductions in systolic blood pressure, especially at doses above 500 mg/day. Daily culinary onion contributes meaningfully to dietary quercetin intake.

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Onion

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Quercetin-rich kitchen staple that supports the heart, immunity, and blood sugar.

Traditional wisdom and modern evidence—clearly explained.

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Evidence: Moderate
Reviewed by: Moji Tehrani, founder
Last reviewed: July 2026

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