What Are Flavonoids?

What Are Flavonoids?

  • There are 12 types of flavonoids, 6 of which are important for humans to eat
  • Eating fruits and vegetables in assorted colors can help you ingest a wide range of flavonoids

Flavonoids are a type of phytonutrient found in most herbs, fruits, and vegetables — from apples and berries to parsley and thyme. There are more than 5,000 total flavonoids divided into 12 different classes. Chances are, you may have eaten at least some flavonoids already today.

They were in the blueberries you had with your breakfast and your morning cup of black tea with soy milk. They were in the pistachios and dried cranberries you had on your salad at lunch. Even the square of dark chocolate you enjoyed this afternoon contained flavonoids!

You’ll find out more about their function and benefits in this article.


What Are Flavonoids and What is Their Function?

“Flavonoids are chemicals found in plants that are responsible for the vivid colors of fruits and vegetables,” says Melissa Mitri, MS, RD, a registered dietitian-nutritionist based in Connecticut.

In addition to supporting your health when you consume them, flavonoids also offer protection for the plants themselves:

  • Flavonoids are responsible for the color and aroma of flowers, and they help attract pollinators to fruit and flowers.
  • They protect plants from stress and disease, and they serve as ultraviolet light filters.
  • They help protect against frost and drought and help plants become more resilient to their environments and the climate.

“Flavonoids are the most prominent subclass of polyphenols, the protective molecules found in plants,” explains Colleen Wysocki-Woods, MS, RDN, owner of ZEST Nutrition.


what are flavonoids - green, red, and yellow bell peppers

What Are the Health Benefits of Flavonoids?

There are more than 5,000 different flavonoids, many of which are antioxidant-like compounds that can help boost overall health by protecting the body against damage from free radicals.


What Foods Contain Flavonoids?

“The best food sources of flavonoids are fruits and vegetables — specifically berriescitrus fruitsgreen leafy vegetables, and peppers,” says Mitri. “Other good sources include tea and red wine.”

Here’s a full list of foods that contain flavonoids (which includes some superfoods):

  • Apples
  • Apricots
  • Berries (red, blue and purple varieties like blueberries, blackberries, cherries, raspberries, and strawberries)
  • Broccoli
  • Celery
  • Chamomile
  • Chili peppers
  • Cinnamon
  • Citrus fruit and juice (including grapefruit, lemons, limes, and oranges)
  • Coffee
  • Dark chocolate
  • Dark leafy greens
  • Ginkgo biloba
  • Grapes
  • Kale
  • Oregano
  • Mint
  • Parsley
  • Peaches
  • Pecans
  • Peppermint
  • Pistachios
  • Plums
  • Red onions
  • Red wine
  • Scallions
  • Soy
  • Spinach
  • Tea (especially white, green, and oolong but also black)
  • Thyme

“The more flavonoids you can aim to get into your diet regularly, the better,” says Mitri. “Most of us do not get nearly enough fruits and vegetables, so incorporating at least one serving of vegetables or fruit with every meal will help you to build your body up with these immune-boosting nutrients.”

Wysocki-Woods says the easiest way to integrate more flavonoids into your diet is by eating more dark-colored berries.

“These are an easy addition to any diet,” she says, noting that most existing research is on blueberries and strawberries. “However, just because there aren’t many research studies on the flavonoids of the other foods doesn’t mean they aren’t effective or have other nutritional benefits to offer.”

Eating assorted colors of fruits and vegetables ensures that you’ll get a greater variety of flavonoids.


What Are the Best Flavonoids?

Of the 12 total types of flavonoids, “six are important in the human diet: anthocyanins, flavones, flavanones, isoflavanones, flavonols, and flavan-3-ols,” says Wysocki-Woods.

“There is no ‘best’ one, but focus on the six mentioned above that have research behind them and frequently appear in the human diet,” she says. “It’s ideal to get one to two servings of flavonoids each day and to vary your flavonoid consumption amongst all six classes within any given month.”

That means you might “choose flavanones (think citrus) one week because there’s a sale on oranges, and the next week enjoy isoflavones in tofu and flavonols in green tea,” she suggests. “I love to get my anthocyanins covered in flavan-3-ols as much as possible (dark chocolate-covered strawberries)! You can’t go wrong.”

These are the categories of flavonoids and the common foods that contain them:

  • Anthocyanins: Red, blue, and purple berries (like blueberries and strawberries); red and purple grapes; red wine
  • Flavanones: Citrus
  • Flavan-3-ols: Teas (white, green, and oolong), cacao, berries, apples, and grape; the best-known one is likely the EGCG (epigallocatechin gallate) found in tea (especially green tea).
  • Flavones: Parsley, celery, hot peppers, and thyme
  • Flavonols: Apples, berries, onions, kale and other dark greens, broccoli, and teas; you might have heard of quercetin or rutin.
  • Isoflavanones: Soybeans, soy foods like tofu, and legumes

Wysocki-Woods stresses that the best flavonoids come from foods — not supplements.

“Remember that flavonoid absorption varies and is greatly increased based on subclass as well as the other food components in which they’re found,” she says. “A key takeaway is that flavonoid absorption is increased when consumed from the whole food source rather than an isolated supplement.”


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