Flavonoid Benefits & Food Sources

by John Staughton (BASc, BFA) last updated -

Enjoying the wide variety of flavonoid benefits is as easy as altering your diet and making more conscious choices about the nutrient-dense food you consume.

What are Flavonoids?

Flavonoids are a large class of plant phytonutrients that allow plants to perform several key functions, such as photosynthesis and water absorption, and give plants their signature colors. There are over 6,000 different types of flavonoids, and each of these powerful antioxidants has its own particular benefit. Flavonoids are one of the explanations given for the health benefits that come from vegetarian and plant-based diets, and researchers are still discovering uses and treatments derived from new flavonoids every day. [1]

Types of Flavonoids

Flavonoids are divided up into several subcategories, with adjustments constantly being made by new research.

A small wooden basket and wooden spoon filled with blueberries on a wooden table

Mini blueberries baskets Photo Credit: Shutterstock

  • Flavones: This category includes luteolin and apigenin. They delay the metabolization of certain drugs and have strong overall antioxidant properties. Celery, parsley, and other herbs are good sources of flavones.
  • Flavonones: These are found primarily in citrus fruit, and include hesperetin, eriodictyol, and naringenin. They are useful in treating inflammation, stress, and cardiovascular health issues. [2]
  • Isoflavones: Found primarily in soybeans and legumes, isoflavones are phytoestrogens, which means they act like the hormone estrogen. Isoflavones include genistein, glycitein, and daidzein.
  • Anthocyanidins: Associated with cardiovascular health, obesity control, and diabetes prevention, these are found in red, blue, and purple berries, and other red or dark-skinned fruit like pomegranates and plums. Anthocyanidins include malvidin, pelargonidin, peoidin, and cyanidin. [3]
  • Flavonols: This group can be found in a diverse array of foods, from onions and leeks to Brussels sprouts, kale, broccoli, tea, and berries. Quercetin is the most famous of this group, known for its antihistamine properties.
  • Flavanols: This category includes catechins, a type of flavanol found in green teas, cocoa, and berries that promotes cardiovascular health, as well as dimers, which are found in black tea and are thought to help lower cholesterol.

Sources of Flavonoids

Flavonoids are found in a huge array of foods, but some of the foods with the highest concentration include: parsley, eggplant, blueberries, black, green, and oolong tea, spinach, citrus fruit, red wine, cocoa, peanuts, bananas, buckwheat, tomatoes, red and green onions, and peppers.

Flavonoid Benefits

Flavonoids may potentially reduce the risk of cancer and neurological diseases. These naturally occurring plant pigments also help in weight loss, diabetes management, and overall health. Let us look at these flavonoid benefits in detail.

Anticancer Potential

Flavonoids are antioxidants, and animal studies have shown them to be effective against several different kinds of cancers. However, human studies have been mixed. While flavonoids have been linked to reductions in breast cancer and gastric cancer, their antioxidant powers aren’t quite as strong as vitamin C and vitamin E. [4]

Neurological Disease Prevention

The antioxidant and anti-inflammatory properties of flavonoids are thought to help prevent and treat damage from certain neurological diseases like Alzheimer’s, Parkinson’s, and dementia. Flavonoids may help increase blood flow to the brain, helping to keep cognitive abilities sharp for longer. According to a study from 2012, published in Free Radical Biology and Medicine, researchers Robert J. Williams and Jeremy Spencer found that higher flavonoid intake significantly age-related cognitive decline over the study period. [5]


One of the most extensive studies on flavonoids was done in the Netherlands and published in 1995 in the Journal of the American Medical Association by Dr. Michael G.L. Hertog et al. In it, flavonoid dietary intake was measured across seven different countries, and was found to make as much as a 25% difference in mortality rates due to cardiovascular disease and cancer. Research is still being done to isolate the precise flavonoids that may contribute to longer life spans. [6] [7]

Weight Loss

The anti-inflammatory powers of flavonoids may help counter leptin resistance in the body. Leptin is a hormone that communicates to the body what fat levels are in the body, and how many calories need to be burned. If leptin resistance occurs, the body ceases to get the leptin signal, and people can find that their metabolisms are slower. This can make any kind of weight loss nearly impossible since the body reads reduced calories as starvation and works harder to conserve calories. Flavonoid-heavy foods, especially red or blueberries and juices, can help break down this resistance, allowing the metabolism to function more efficiently. [8]

Diabetes Control

Flavonoids have been linked to the metabolic processes of diabetes II, especially when it comes anthocyanins. They are thought to help regulate glucose and insulin, as well as reduce inflammation. In animal studies, flavonoids led to reduced aldose reductase, increased insulin, and regeneration of damaged pancreatic beta cells. This can be a game-changer for diabetic patients who want to manage their blood sugar in a healthier way and prevent dangerous spikes and drops in glucose levels. [9]

Cardiovascular Disease

The link between flavonoids and a lowered risk of cardiovascular disease is well documented, but the actual mechanics are still being investigated as scientists try to determine which flavonoids are actually responsible for preventing which conditions. Quercetin has been linked to a lowered risk of ischemic heart disease, as well as asthma and lung cancer. Kaempferol, naringenin, and hesperetin were all found to lower the risk for cerebrovascular disease. Multiple flavonoids have been found to help prevent blood clotting, which reduces the risk of heart attack and stroke. [10]

Side Effects

In high doses, the side effects of flavonoid supplementation may outweigh the good. Different flavonoids may have different effects; for instance, quercetin can cause kidney damage in large doses. Other side effects can include nausea and headaches. Most experts recommend getting flavonoids through dietary sources, rather than as supplements. As with any alteration to a health regimen, it is best to speak with your doctor before making major changes to your nutrient intake.

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About the Author

John Staughton is a traveling writer, editor, publisher and photographer with English and Integrative Biology degrees from the University of Illinois in Champaign-Urbana (USA). He co-founded the literary journal, Sheriff Nottingham, and now serves as the Content Director for Stain’d Arts, a non-profit based in Denver, Colorado. On a perpetual journey towards the idea of home, he uses words to educate, inspire, uplift and evolve.

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