Onion

Studies in people

• Open question

  Heart and body measures²

  People taking onion supplements saw changes in cholesterol, blood pressure, body fat, weight, and liver markers.

• Benefit

  Cholesterol and heart health³

  In people with slightly high cholesterol, garlic and onion extracts lowered bad cholesterol and total cholesterol.

• Concern

  Food allergy symptoms⁴

  In people, onion caused allergy symptoms in a small number of those tested, linked to a specific protein.

Animal and lab studies only

• Benefit

  Lab study health effects⁷

  In lab studies, onion extracts and compounds showed antimicrobial, antidiabetic, anti-inflammatory, anticancer and other activities.

Study type not stated

• Open question

  Overall health effects⁵

  Compounds in onion have been reported to affect cancer, blood clotting, asthma, and bacterial infections.

• Benefit

  General health benefits⁶

  Green onions add flavor and nutrients to meals, and traditional diets with them are linked to health benefits.

The signal at the top counts the findings in people and in animal and lab studies. A concern in studies of people outranks animal and lab studies, and “No concerns” needs at least two findings in people. Findings whose study type is not stated are shown but not counted. This page is a reference, not medical advice. It describes what regulators and published research say. Talk to a doctor or dietitian about your own diet.