The best foods high in flavonoids (and why they matter)

Looking to increase your antioxidant intake to fight off inflammation and illness? You might want to eat more flavonoids. These powerful plant compounds – found in everything from berries to dark chocolate – are a favourite among biohackers for their potential to protect your cells, strengthen your immune system and support your long-term health.

Here’s why we’re such big fans of them and the foods to add to your diet to maximise their benefits.

What are flavonoids?

Flavonoids are natural compounds found in plants. They’re vital for the growth and reproduction of different plants, helping to attract pollinators to ensure their survival and protect them from stressors in their environment. They also give plants their colour and taste.

Flavonoids can offer many health benefits to us humans, too. They have natural antioxidant and anti-inflammatory properties, and there’s some evidence indicating that they may boost brain function and  protect us from certain health conditions.

Luckily, you don’t have to go far to find them. Some of the most common foods contain flavonoids, including berries, kale, tomatoes, cabbage, citrus and onions. You might also be pleased to learn that dark chocolate and red wine are a great source of them, too.

What do flavonoids do in the body?

Flavonoids are pretty potent little compounds. When they enter the body, they:

• Neutralise free radicals: Free radicals are unstable molecules that can damage cells, DNA and tissue. This type of damage (known as oxidative stress) contributes to ageing and multiple health issues. Flavonoids are high in antioxidants, which have the capacity to stabilise free radicals, reduce inflammation and improve immunity [1]
• Provide antimicrobial and antifungal properties: Some flavonoids – such as those found in green tea and citrus – can disrupt the growth of bacteria and fungi. They do this by breaking down cell walls, blocking reproduction and effectively starving bacteria and fungi so they can’t survive or multiply [2]

Types of flavonoids

It’s estimated that there are anywhere from 6,000-10,000 types of flavonoids. However, when it comes to human health specifically, there are six dietary flavonoids considered the most important:

• Flavanols: Found in onions, grapes and kale, these flavonoids have major antioxidant properties
• Flavan-3-ols: Many tea varieties contain flavan-3-ols – including black, white and green – which have both antioxidant and anti-inflammatory effects
• Flavones: Flavones also have antioxidant and anti-inflammatory powers and occur naturally in celery, parsley and citrus peel
• Flavanones: These flavonoids are largely found in different citrus fruits and have antioxidant and anti-inflammatory properties
• Isoflavones: Soybeans and other soy products like tofu and miso are rich sources of isoflavones, which are believed to support hormone health
• Anthocyanins: Anthocyanins have potent antioxidant properties and give plants their red, purple, blue and black colours. That’s why you’ll mostly find them in berries, grapes and red wine

What are the potential health benefits of flavonoids?

We know now that flavonoids are hugely powerful when it comes to their antioxidant, antifungal and antimicrobial properties. But how does this actually benefit the body? Here are just some of the possible health benefits of consuming flavonoids:

• They can calm inflammation: Ongoing oxidative stress can lead to inflammation, a root cause of many chronic diseases. Thanks to their high antioxidant content, lots of research has demonstrated flavonoids’ abilities to reduce inflammation and potentially offer protection from these debilitating conditions [3]
• They can ward off common illnesses: The antibacterial, antiviral and antifungal properties of flavonoids allow them to fight or weaken certain microbes, such as the flu
• They may slow ageing: Research shows that flavonoid intake is linked to a higher chance of healthy ageing, warding off many age-related diseases and contributing to a longer life with better overall health [4]
• They can help manage diabetes: Beyond their anti-inflammatory effects, some evidence suggests that flavonoids can improve insulin sensitivity and help manage blood sugar levels [5]
• They can improve heart health: Flavonoids can improve blood flow, reduce blood pressure, decrease bad cholesterol and prevent artery hardening [6]
• They can support brain health: Flavonoids’ antioxidant powers may help protect the brain from certain neurodegenerative diseases [7]

What are some foods high in flavonoids?

By now, you’re probably wondering which flavonoid-rich foods to add to your diet. The good news is that there’s a wide variety of foods that contain flavonoids, so you’re spoilt for choice when it comes to stepping up your intake.

Fruits

• Apples (especially the skin)
• Berries (blueberries, blackberries, raspberries, strawberries)
• Grapes (particularly red and purple grapes)
• Citrus fruits (oranges, lemons, limes, grapefruits)
• Cherries
• Plums
• Apricots
• Pomegranates
• Mangoes
• Peaches
• Pears
• Kiwifruit

Vegetables

• ​​Onions (particularly red and yellow)
• Kale
• Broccoli
• Cabbage (red and green)
• Spinach
• Brussels sprouts
• Celery
• Parsley
• Capsicum (especially red)
• Artichokes
• Asparagus
• Lettuce (red leaf and romaine)

Drinks

• Green tea
• Black tea
• White tea
• Rooibos tea
• Honeybush tea
• Red wine
• Cocoa and dark chocolate drinks
• Coffee
• Citrus or berry juices

Other plant-based sources

• Soy foods (soybeans, tofu, tempeh, miso)
• Legumes (beans, lentils, chickpeas)
• Herbs (thyme, mint, dill, basil)
• Spices (turmeric, cinnamon)
• Nuts (especially almonds and walnuts)
• Seeds (flaxseed, chia)
• Extra virgin olive oil
• Whole grains (buckwheat, oats, barley)
• Dark chocolate

What’s the dietary flavonoid intake?

Unlike protein, fibre and minerals like iron, there’s no official recommended daily intake for flavonoids. However, research suggests that you’ll reap significant health benefits by consuming around 500mg of flavonoids daily. In fact, some experts suggest that the benefits plateau if you consume more than that [8].

So, what does 500mg look like, and how can you ensure you’re getting enough flavonoids each day?

500mg is about the equivalent of 1-2 cups of tea and two portions of fruit [9].

However, experts generally agree that maintaining a healthy diet rich in lots of different types of fruits and vegetables, and following the “5 a day rule” should keep your intake on track. That means aiming for two portions of fruit and three portions of veg each day. Eat for Health counts 75g of fresh, canned or frozen fruit and vegetables as one portion.

How to include more flavonoid-rich foods in your diet

Because there’s such a diversity of foods rich in flavonoids, it’s relatively easy to get more into your diet. But if you need a bit of meal-planning inspiration, here are some ideas.

Drink more tea

Different types of tea are some of the best sources of flavonoids. Black, white and green are particularly high in flavonoids, but if you’d prefer to avoid caffeine, several herbal varieties contain a decent amount of them, too. Examples include chamomile and rooibos.

Try a flavonoid-packed smoothie

A smoothie is an easy way to get lots of flavonoids in at once. Mix up a variety of berries, throw in some kale and add some chia or flaxseeds for an additional boost.

Add veg-based sides

Incorporating more veg into your diet is never a bad idea, but now you’ve got even more reason to. Whip up some easy vegetable-based side dishes for your lunches and dinners, like sauteed kale or Brussels sprouts, steamed broccoli, or a salad made with lettuce, cabbage or baby spinach. Ramp up the flavonoids further by adding a drizzle or dressing made with extra virgin olive oil.

Stock up on healthy snacks

Instead of reaching for crisps or biscuits, consider replacing your favourite snacks with fruit, carrot sticks and hummus, or a handful of raw nuts.

Treat yourself

Red wine and dark chocolate are particularly high in flavonoids, so here’s an excuse to include them in your diet. Just remember to enjoy them in moderation, particularly red wine. Excessive alcohol may counteract many of the health benefits you’re trying to get from consuming more flavonoids.

Swap meat for plant foods

If you’re used to eating meat every day, consider occasionally swapping it out for plant-based products like tofu, tempeh or legumes. Not only will you increase the amount of flavonoids in your meals, but you’ll also boost your consumption of fibre, vitamins and minerals.

Spice up your cooking

Using ingredients like onions, spices and fresh herbs in your meals can ramp up your flavonoid intake. 

Aim for five a day

Eating at least two serves of fruit and three serves of veg should get you to the ideal amount of flavonoids recommended for optimal health. As an example, one serve of fruit is one apple or a cup of berries, while one serve of veg is half a cup of cooked vegetables or one cup of salad.

Diversify your plate

Rather than sticking to berries or dark chocolate, eating a wide range of flavonoid-containing foods is the best way to get adequate variety and consume a diversity of beneficial compounds.

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