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Flavonoids

Table of Contents

What are flavonoids?

Flavonoids are natural compounds found in plants that give fruits and vegetables their colors [3]. These molecules act as antioxidants, protecting your cells from damage caused by free radicals. Higher intake of flavonoid-rich foods is consistently linked to better heart health, improved cognitive function, and reduced risk of chronic diseases.

Where to find flavonoids

Berries are among the best sources, especially blueberries, blackberries, and strawberries. Tea, particularly green and black varieties, provides significant amounts. Dark chocolate with at least 70% cocoa, citrus fruits, onions, and red wine also contain high levels. Eating a variety of colorful plant foods ensures you get different types of flavonoids.

Types and their benefits

Quercetin, found in apples and onions, supports immune function and may reduce allergy symptoms. Anthocyanins give berries their blue and red colors and cross into the brain to protect neurons [2]. Catechins in green tea promote fat oxidation and cardiovascular health. Each type offers unique benefits, which is why dietary variety matters.

Heart health protection

Flavonoids improve blood vessel function, reduce inflammation, and help prevent LDL cholesterol from oxidizing. A meta-analysis found that people who consume the most flavonoids have up to 18% lower risk of cardiovascular events [1]. Regular consumption of flavonoid-rich foods supports healthy blood pressure and reduces arterial stiffness.

References

  1. 1. Flavonoid Intake and Cardiovascular Disease Risk
  2. 2. Dietary Flavonoids and Cognitive Function
  3. 3. Flavonoids as Antioxidants: Mechanisms and Benefits
1.

Freeze berries for year-round access

Frozen berries retain most of their flavonoid content and are often more affordable than fresh. Add them to smoothies, oatmeal, or yogurt without thawing first.
2.

Brew green tea properly

Use water at 160-180°F (70-80°C), not boiling, to preserve catechins. Steep for 2-3 minutes. Over-brewing releases tannins that make tea bitter and may reduce beneficial compounds.
3.

Choose dark chocolate

Select chocolate with at least 70% cocoa content for meaningful flavonoid intake. One ounce (28g) of 85% dark chocolate provides more flavonoids than milk chocolate while keeping sugar low.
4.

Eat onions raw when possible

Raw onions contain more quercetin than cooked ones. Add sliced red onions to salads, sandwiches, or tacos. Cooking reduces flavonoid content by 20-50%.
5.

Eat the whole fruit, not just juice

Citrus flavonoids concentrate in the white pith and membranes between segments. Eating whole oranges or grapefruit provides more benefits than juice alone.
1.

What are polyphenols and how do they relate to flavonoids?

Polyphenols are a broad category of plant compounds with antioxidant properties. Flavonoids are the largest and most studied subgroup of polyphenols. Other polyphenol types include phenolic acids (found in coffee and whole grains), stilbenes (like resveratrol in grapes), and lignans (in flaxseeds). All polyphenols offer health benefits, but flavonoids are particularly abundant in fruits and vegetables.
2.

Can flavonoid supplements replace whole foods?

No. Whole foods contain complex mixtures of flavonoids along with fiber, vitamins, and other beneficial compounds that work together. Isolated flavonoid supplements have shown mixed results in studies and may not provide the same benefits. Some high-dose supplements can even interfere with medications. Focus on getting flavonoids from a varied diet of colorful plants.
3.

How much tea should I drink for health benefits?

Studies showing cardiovascular and cognitive benefits typically involve 2-3 cups of green or black tea daily. This provides approximately 200-300 mg of flavonoids. More is not necessarily better—excessive caffeine from tea can cause sleep disruption and anxiety. If you're sensitive to caffeine, consider decaffeinated green tea which retains most flavonoids.
4.

Do flavonoids survive cooking and processing?

Flavonoid content varies with preparation. Light steaming preserves most flavonoids in vegetables. Boiling causes some loss into cooking water, though using that water in soups retains them. Processing like juicing removes fiber but keeps many flavonoids. Freezing preserves berry flavonoids well. Baking with whole grain flour retains more flavonoids than refined flour products.
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This content was created and reviewed by the New Zapiens Editorial Team in accordance with our editorial guidelines.
Last updated: February 26, 2026
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