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.

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.

Chapter 1 of 21

Onion

If You Read Nothing Else

One of the densest dietary sources of quercetin — a long-life flavonoid (a family of protective plant compounds).

Studied for blood pressure, cholesterol, and blood-sugar balance. Prebiotic (fibre that feeds the helpful bacteria in your gut) inulin feeds a healthy gut microbiome.

Healthy blood vessels and a diverse gut microbiome are two of the strongest predictors of healthspan. Onion supports both quietly, for pennies, every day — a quintessential aging-well staple.

May help lower LDL (the harmful type of cholesterol) cholesterol and triglycerides (a type of fat in the blood).