Want to Improve Your Immune System?
Then Here’s What You Need to
Know about Flavonoids


For the first time ever, a study has proven that eating flavonoids, a type of antioxidant that’s especially concentrated in fruits and vegetables, may boost your immune system.

flavonoids in fruit

If you eat a lot of fresh fruits and veggies, you’re likely getting plenty of flavonoids. Be aware, however, that cooking and processing greatly reduces these healthy compounds in your food.

How did the researchers come to this realization? By watching birds.

Researchers from the University of Freiburg and the Max Plank Institute for Ornithology in Germany offered blackcaps a choice of two foods; they were identical except one contained more flavonoids. Sure enough, the birds chose to eat the foods that contained the extra antioxidants.

Next, they looked into what impact the flavonoids had on the birds’ health. Compared with birds not fed flavonoids, those that ate modest amounts of the healthy antioxidants for four weeks had stronger immune systems.

“We fed the birds an amount of flavonoids that they would obtain by eating 1-2 blackberries, bilberries or elderberries a day,” said the lead author of the study, Carlo Catoni of the University of Freiburg.

“We used this modest intake of flavonoids because high quantities are only available during the limited time of maximum berry abundance. Our study shows for the first time that flavonoids are beneficial compounds that can boost the immune system in a living organism,” he continued.

What are Flavonoids?

Flavonoids are actually classified as plant pigments because they’re the substances that contribute to the red color in grapes, and countless other shades of yellow, orange and red in plants. In fact, there are over 6,000 types of flavonoids, and they’re found in virtually all plants.

In your body, flavonoids act as powerful antioxidants that neutralize damage from free radicals. They’re known to:

  • Help protect your blood vessels from rupture or leakage
  • Enhance the power of vitamin C
  • Protect your cells from oxygen damage
  • Prevent excessive inflammation in your body
flavonoids in green tea

Along with fruits and veggies, green tea is an excellent source of flavonoids.

They are also known to support a healthy immune system, which is why if you get a lot of colds or infections, your body may be lacking in these healthy compounds. It is convenient and also possible to get flavonoids in supplement form. Other signs that you’re not getting enough flavonoids include:

  • Bruising easily
  • Getting frequent nose bleeds
  • Excessive swelling after injury
  • Hemorrhoids

    Making sure to get plenty of vitamin C with bioflavonoids will help support the collagen that surrounds blood vessels and thereby help lessen easy bruising and frequent nose bleeds.

Are You Getting Enough Healthy Flavonoids?

Because flavonoids exist in nearly all fruits, vegetables, herbs and spices, it’s not difficult to get plenty of these antioxidants from your diet. However, if you don’t eat many fresh fruits and veggies, and instead rely on mostly processed food, you could be missing out — flavonoids are highly susceptible to damage from processing and cooking.

For example, boiling fresh spinach removes half of the total flavonoid content, and overcooking veggies is known to significantly reduce levels as well.

Keeping that in mind, some of the best sources of flavonoids include:

  • Apples
  • Apricots
  • Blueberries, raspberries and strawberries
  • Pears
  • Black beans and pinto beans
  • Cabbage
  • Onions
  • Parsley
  • Tomatoes

You can also get significant amounts of flavonoids by drinking red wine and green tea, which has about 1,000 mg per cup. For comparison, black raspberries contain about 100 mg per ounce, and clinical studies using flavonoids often use levels in the 500-3,000 mg range.


Functional Ecology, Volume 22 Issue 2 Page 303-310



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