We are independent & ad-supported. We may earn a commission for purchases made through our links.

Advertiser Disclosure

Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.

How We Make Money

We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently from our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.

What are Flavonoids?

By J. Beam
Updated Mar 03, 2024
Our promise to you
The Health Board is dedicated to creating trustworthy, high-quality content that always prioritizes transparency, integrity, and inclusivity above all else. Our ensure that our content creation and review process includes rigorous fact-checking, evidence-based, and continual updates to ensure accuracy and reliability.

Our Promise to you

Founded in 2002, our company has been a trusted resource for readers seeking informative and engaging content. Our dedication to quality remains unwavering—and will never change. We follow a strict editorial policy, ensuring that our content is authored by highly qualified professionals and edited by subject matter experts. This guarantees that everything we publish is objective, accurate, and trustworthy.

Over the years, we've refined our approach to cover a wide range of topics, providing readers with reliable and practical advice to enhance their knowledge and skills. That's why millions of readers turn to us each year. Join us in celebrating the joy of learning, guided by standards you can trust.

Editorial Standards

At The Health Board, we are committed to creating content that you can trust. Our editorial process is designed to ensure that every piece of content we publish is accurate, reliable, and informative.

Our team of experienced writers and editors follows a strict set of guidelines to ensure the highest quality content. We conduct thorough research, fact-check all information, and rely on credible sources to back up our claims. Our content is reviewed by subject matter experts to ensure accuracy and clarity.

We believe in transparency and maintain editorial independence from our advertisers. Our team does not receive direct compensation from advertisers, allowing us to create unbiased content that prioritizes your interests.

Flavonoids are a type of compound found in many different foods. There are several thousand types, which are broken down into six subgroups: chalcones, flavones, flavonols, flavanones, anthocyanins, and isoflavonoids. They all serve a variety of functions in plants, and are thought to be associated with a number of health benefits for humans. They may be connected with some adverse health conditions as well, but there are no widely-reported side effects. There are many different sources of flavonoids, including berries, tea, wine, beer, chocolate, many vegetables, and most fruits.

Potential Health Benefits

Research on the potential health benefits of these compounds is mostly focused on the way they interact with other substances, especially in terms of their antioxidant activity. Antioxidant substances are able to change or neutralize the effects of reactive substances called free radicals that can damage cells, leading to disease. Many of the studies on flavonoids have been done on materials in test tubes or animals, so it's not entirely clear how effective they are in humans, but they may lower the risk of a variety of health problems, including cardiovascular disease, age-related degenerative diseases, and cancers. They may also help prevent tooth decay and reduce the occurrence of common illnesses, like the flu.

Flavonoids appear to have a symbiotic relationship with vitamin C, and are thought to change the way that cells associated with inflammation act, preventing or reducing it. Several studies show that they can disrupt the function of certain viruses and bacteria, including those associated with Human Immunodeficiency Virus (HIV) and certain types of herpes. They may also improve symptoms related to psychological disorders, including mood instability, memory problems, and depression.

Potential Side Effects

There are no widely known side effects of flavonoids, even when they are taken in very large concentrations; however, some people do appear to have individual sensitivities to specific kinds. One type, catechin, can cause a fever, anemia, and hives, though this is uncommon. Several studies showed that these substances do cause changes in certain genes like those associated with some cancers, but these results have not been seen in other studies.

Sources and Consumption

Most fruits and berries contain these compounds, though blueberries, cranberries, bananas, oranges, and apples are known for being particularly flavonoid-rich. Vegetables, especially broccoli, onions, spinach, eggplant, and tomatoes, are excellent sources as well. Beer, red wine, various nuts and beans, and dark chocolate also contain flavonoids, as do a wide range of teas. It's best to consume this nutrient directly from foods as part of a varied diet, rather than via a dietary supplement, as the effectiveness of isolated flavonoids is unclear. Cooking, processing, and high acidity environments all reduce the amount of flavonoids in foods.

Role in Plants

In plants, these substances provide pigmentation and help filter UV rays. They also help protect the plants from microbe, fungus, and insect attacks; and help plants survive frost and droughts. Additionally, they help promote or inhibit the growth of certain plant parts, including seeds and pollen tubes, and are used as chemical signals to tell plant cells when to stop or start doing things.

The Health Board is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.

Discussion Comments

By usiusk — On Feb 19, 2015

Do flavonoids have structure and to which subgroup is that of the onions?

By anon984950 — On Jan 12, 2015

My pharmacist husband always prompted me about this topic and now that I have read it I will be aware of these sources.

By wavy58 — On Jan 20, 2012

@StarJo – If flavonoids enable our bodies to get more vitamin C, then that is probably what keeps us from getting so many infections and illnesses. I drink grapefruit juice every morning, and I imagine that it is a major factor in my good health.

I used to be a sickly person. I would bruise very easily, and often I could not remember how I hurt myself. I got frequent nosebleeds, and I seemed to stay sick with a cold.

My doctor actually told me that I probably needed to be consuming more flavonoids. She was so right. My body feels stronger now, and I am so glad that all I had to do was start eating better foods.

By cloudel — On Jan 19, 2012

@seag47 – Flavonoids help keep me healthy, too. After a particularly miserable winter when I got three terrible upper respiratory infections, I decided to try eating healthier.

I'm not crazy about blueberries and red beans, but there are some other flavonoid-rich foods that I eat on a regular basis. Apples are a good source, as well as strawberries. These are my two favorite fruits, and I always feel good after eating them.

On the vegetable side, black beans and tomatoes are good sources. I like to eat chicken tortilla soup, which includes both of these. Both are also excellent in tacos with some type of meat.

By seag47 — On Jan 18, 2012

I used to think that the only thing that could keep me from getting the flu was a flu shot, but I believe that changing my diet to include more flavonoids is what has kept me healthy during the last few flu seasons. I stopped getting flu shots, yet I haven't caught it.

I developed a love for blueberries. I put them in oatmeal, cereal, and even in the batter of my pancakes. Sometimes, I eat them by themselves.

I have also found that red beans taste great if you boil them with a little bit of beef bouillion in the water for extra flavor. I also like to add noodles to the mix to make it a meal.

I feel better inside since I have begun consuming more flavonoids. Can anyone tell me some more foods that contain high amounts? I want to add more to my diet.

By StarJo — On Jan 18, 2012

I have read that certain flavonoids help our bodies absorb vitamin C. In fact, this vitamin would not be nearly as useful without their help.

Flavonoids can also increase our bodies' absorption of drugs. There is one flavonoid in grapefruits that is particularly good at this.

When I was involved in a clinical study of a drug used to treat polycystic kidney disease, I was told to avoid grapefruit while on the drug. Had I eaten any, my body could have absorbed more of the medication than necessary, and since this drug is experimental, they didn't know exactly what would happen.

Since grapefruit juice is often included in the punch at showers and weddings, I had to remember not to drink any of it. This was hard, because I went to over five events like this during the time I was on the study, and I had to sneak in a bottle of water each time.

By anon241058 — On Jan 17, 2012

Flavonoids are very beneficial and more and more research is proving it. Believe it or not, but cocoa or unprocessed dark chocolate has one of the highest antioxidant values known.

By anon147633 — On Jan 29, 2011

how do flavonoids affect treating wound infection or in wound healing? thanks for the answers.

By anon26977 — On Feb 22, 2009

what extraction method may be used in flavonoids??

and is it possible to separate flavonoids in chromatography?? how??--tnx 4 d reply

By catapult43 — On May 04, 2008

Flavonoids have antioxidant powers and act as free radical scavengers. They are effective in suppressing inflammation. It is good to eat a cornucopia of vegetable and fruit to keep us healthy, young, and slim.

The Health Board, in your inbox

Our latest articles, guides, and more, delivered daily.

The Health Board, in your inbox

Our latest articles, guides, and more, delivered daily.