Vibrant yellow lemons, crimson tomatoes, rose-colored cherries, leafy green kale, verdant broccoli, bronze-skinned shallots. What is one nutrient this rainbow of foods has in common?
Quercetin. Quercetin is a flavonoid — a polyphenol found abundantly in many fruits, vegetables, and grains. Flavonoids act as natural pigments, giving fruits, vegetables, flowers, and leaves their brightly colored hues. Beyond providing an appealing palette for the senses (useful for both pollination and seed distribution), flavonoids help protect plants by absorbing UV radiation and defending against pathogens.1 Some flavonoids even act as insect deterrents, protecting plants from infestation.2
All this nutritive protection for plants translates to some pretty big health benefits for humans. Flavonoid intake has been associated with healthy aging and a reduced risk of all-cause mortality, according to epidemiological studies.3,4 , In addition to acting as potent antioxidants, flavonoids are known to contribute to a healthy inflammatory response, thus supporting immune health and overall well-being.5
A rainbow of benefits
Science has identified over 6,000 unique flavonoids, with quercetin being among the most common, accounting for roughly 75% of the flavonoids in foods we humans typically consume.6 Quercetin is also among the most commonly studied flavonoids,7 and has been shown to:
- Help neutralize damaging free radicals and oxidative stress in the body.8
- Enhance tight junction proteins and improve mucosal thickness, thus supporting healthy gut barrier integrity.9
- Balance gut microbiota and improve diversity of the microbial community.10
- Inhibit the production of certain compounds from the immune system, thus contributing to a healthy inflammatory response.11
- Stabilize mast cells (immune cells that release histamine and other compounds during an allergic reaction), which may help with symptoms associated with seasonal allergies including runny nose, watery eyes, hives and swelling.12
- Help maintain healthy blood pressure and cholesterol levels already in the normal range.13
- Assist with healthy blood sugar metabolism, especially after meals.14
- Help maintain healthy cell growth.15
Dietary sources of quercetin
Quercetin is found in a variety of fruits, vegetables, grains, and leaves – and also in beverages sourced from flavonoid-rich plants. Some of the main dietary sources of quercetin include:
- Onions and shallots
- Green tea
- Grapes & red wine
- Cruciferous vegetables (broccoli, kale, cabbage)
- Cherry tomatoes
- Citrus fruit peels Ginkgo biloba
- Apples (found mostly in the skin)
There’s a reason why we’re told to “eat the rainbow.” Eating a varied diet high in vegetables, fruits, and organic teas is a great way to get healthy levels of this beneficial flavonoid. Quercetin is also available as a dietary supplement – look for formulas derived from plant sources rather than those that are synthetically produced.
When it comes to maintaining health and wellness, making food and lifestyle choices to include more quercetin in your diet is worth the extra effort. In fact, it just might be the “low-hanging fruit” you’ve been searching for.