WHAT IS IT?
Quercetin is the most abundant flavonoid in the human diet, providing you eat a diet high in fruits and vegetables. A flavonoid is a plant pigment with antioxidant properties. Quercetin is found in many fruits, vegetables and herbs and is safe to consume.
WHERE CAN IT BE FOUND?
Quercetin is found naturally in many plant foods, particularly in the outer layer or peel. Onions are the food found to have the highest amount of quercetin.
- Food Sources:
- Red Apples
- Red Grapes
- Citrus Fruits
- Leafy Greens: Red Leaf Lettuce, Kale, etc.
- Sweet Peppers
- Tea: Green, Black & Buckwheat
The amount of quercetin in foods may depend on the conditions in which the food was grown. Organic sources have been shown to have higher concentrations than their conventionally grown counterparts.
It’s estimated that the average person consumes 10–100 mg of quercetin daily from fruits, vegetables, and herbal sources.
WHAT ARE ITS HEALTH BENEFITS?
The health benefits of flavonoids, like quercetin, come from their antioxidant functions inside the body. Antioxidants bind and neutralize free radicals, preventing them from causing cellular damage. This damage leads to inflammation. Normally, the inflammation goes away after the immune system eliminates the offender or repairs the damaged tissue. When the body is unable to do this, the inflammation becomes chronic and may lead to numerous chronic conditions, including:
- Heart disease
- Kidney disease
- Autoimmune conditions
- In an 8-week study of 50 women with rheumatoid arthritis, it was observed that the women who took 500 mg of quercetin daily experienced significantly reduced early morning stiffness, morning pain, and after-activity pain. They also had reduced markers of inflammation, such as TNFα, compared to those who received a placebo. (Pub Med)
- This research is promising but more research in humans is needed.
ARE THERE BENEFITS OR DANGERS TO TAKING IT AS A SUPPLEMENT?
When consumed in food, quercetin is generally safe for everyone, including pregnant and breastfeeding women. Because studies on safety of quercetin supplements are lacking, supplements should be avoided if you are pregnant or breastfeeding.
Quercetin may interact with various medications, including blood thinners, blood pressure medications, and antibiotics. Speak with your health care provider before taking any supplement, including quercetin.
As a supplement, quercetin appears to be generally safe with little to no side effects and many potential benefits.
Typical dosages range from 500–1,000 mg per day
Taking more than 1,000 mg of quercetin per day may cause mild symptoms:
- Tingling sensations in the arms and legs
Very high doses of quercetin may damage the kidneys.
- People with kidney disease should avoid quercetin
Quercetin has been safely used in amounts up to 500 mg twice daily for 12 weeks.
- It is unknown if long-term use or higher doses are safe
- Taking periodic breaks from taking quercetin may be a good idea
On its own, as a supplement, quercetin has a low bioavailability, which means your body absorbs it poorly.
People take this supplement for several reasons, including to:
- Boost immunity
- Fight inflammation
- Combat allergies
- Increase exercise performance
- Maintain general health
The benefits of Quercetin are promising but more human research is needed.