Which foods are highest in polyphenols?

Polyphenols are a micronutrient found in many plant-based foods. Although polyphenols are available in supplement form, it’s best to consume them in natural foods. 

There are over 8,000 types of polyphenols. The four main categories are:

• Flavonoids: These are found in colorful fruits, vegetables, tea, and wine.

• Phenolic acids: These are found in the seeds, skins, and leaves of fruits and vegetables.

• Lignans: These are found in whole grains, nuts, and seeds.

• Stilbenes: These are abundant in peanuts, grapes, and berries.

Over the last decade, polyphenols have attracted a lot of interest. Research suggests that they have several health benefits, including supporting a healthy heart.  

Health benefits of polyphenols

According to a 2018 review, a diet rich in polyphenols may help protect you from chronic health conditions, including certain cancers, heart disease, type 2 diabetes, and neurodegenerative diseases. 

Polyphenols are:

• Antioxidants: These can protect cells from damage caused by free radicals.

• Anti-inflammatory: Polyphenols have anti-inflammatory properties that might help prevent many chronic conditions. 

• Neuro-protective: The antioxidant effects of polyphenols may protect against neurological diseases such as dementia and Alzheimer's. 

• Good for insulin sensitivity: Polyphenols may help control blood sugar levels, improve insulin sensitivity, and lower your risk of developing type 2 diabetes. 

• Good for heart health: Several studies have shown that a diet high in polyphenols may reduce the risk of coronary heart disease. 

Polyphenols are also good for your gut bacteria. Experts believe that they contribute to gut health by promoting the growth of beneficial gut bacteria or inhibiting “bad” gut bacteria. 

ZOE's research is slowly uncovering the many ways that a thriving gut microbiome can boost general health.

Our scientists have identified 15 "good" bacteria associated with positive health markers and 15 "bad" bacteria linked to negative health outcomes.

If you'd like to know which bugs live in your gut, start by taking our free quiz today. 

1. Berries

Berries are high in polyphenols such as anthocyanins, flavonols, and phenolic acids. The berry highest in polyphenols is the black chokeberry (native to eastern North America), which has over 1,700 milligrams (mg) of polyphenols per 100 grams (g).

More common berries high in polyphenols include:

• elderberries: 1,191 mg per 100 g

• blackcurrants: 560 mg per 100 g

• blueberries: 525 mg per 100 g

• blackberries: 248 mg per 100 g

• strawberries: 225 mg per 100 g

• raspberries: 126 mg per 100 g

It's worth noting that anthocyanins — polyphenols responsible for the color of some fruits and veg — are mainly present in the skin. Therefore, if a juice doesn't include the skin, it will lose much of its polyphenol content.

2. Cocoa

Cocoa powder contains 3,448 mg of polyphenols per 100 g. 

However, not all chocolate boosts your polyphenols in the same way — always check the cocoa content. For instance, there's a big difference between milk and dark chocolate:

• dark chocolate: 1,664 mg per 100 g 

• milk chocolate: 236 mg per 100 g

Look for good quality dark chocolate with 70% or greater cocoa content for the highest levels of polyphenols. 

3. Coffee and tea

If you like to start your day with a nice cup of coffee or tea, then you'll be pleased to know that there are polyphenols in both:

• filter coffee: 214 mg per 100 milliliters (ml) 

• black tea: 102 mg per 100 ml 

• green tea: 89 mg per 100 ml 

It’s worth noting that the storage and roasting process of coffee beans does affect the polyphenol content. 

For instance, research has shown that organic coffee beans have a higher polyphenol content than conventional ones. 

Also, when coffee beans are stored, polyphenol levels decrease over time. The intensity of the roasting process also plays a part: Fresh, light-roasted beans seem to have a higher polyphenol content than medium-roasted beans. 

4. Spices

Although many spices have high levels of polyphenols per gram, because you only use small amounts, they provide fewer polyphenols overall. For instance, you are unlikely to eat 100 g of cloves in a day. 

• cloves: 15,188 mg per 100 g 

• star anise: 5,460 mg per 100 g 

• curry powder: 285 mg per 100 g 

Turmeric — which has anti-inflammatory and antioxidant properties — contains a polyphenol called curcumin. Studies show that the total polyphenol content of curcumin is around 2,213 mg per 100 g, which is relatively high. 

However, turmeric only contains 2–5% curcumin, so you won't get a vast amount when adding turmeric to your meal. 

Curcumin is also difficult for your body to absorb and only a tiny amount of what you consume reaches your bloodstream.

5. Nuts and seeds

Nuts and seeds are high in plant protein, nutrients, and polyphenols. The top five for polyphenol content are:

• flaxseed meal: 1,528 mg per 100 g

• chestnuts: 1,215 mg per 100 g 

• hazelnuts: 495 mg per 100 g 

• pecan nuts: 493 mg per 100 g 

• almonds: 187 mg per 100 g 

To put this into context, a serving size of 10 chestnuts weighs approximately 84 g.

Alongside 1,020 mg of polyphenols, this serving will give you 2.66 g of protein, 4.28 g of fiber, and 21.8 mg of vitamin C, amongst other nutrients.  

6. Red wine

Alcohol is not the healthiest beverage of choice, but some alcoholic drinks may provide health benefits in moderation. 

Because red wine is produced using the skin of the grapes, it has a much higher polyphenol content than other wines:

• red wine: 101 mg per 100 ml

• rosé wine: 10 mg per 100 ml

• white wine: 10 mg per 100 ml

7. Olives (and olive oil)

Olives are rich in vitamin E, fatty acids, and polyphenols. They are a staple part of the Mediterranean diet. 

• black olives: 569 mg per 100 g

• green olives: 346 mg per 100 g

• extra-virgin olive oil: 62 mg of per 100 ml

8. Beans 

Beans are nutrient-rich, and this includes polyphenols:

• black beans: 59 mg per 100 g 

• white beans: 51 mg per 100 g 

High in protein, dietary fiber, and vitamins, beans make a great addition to soups and salads. 

9. Vegetables

Although vegetables generally have fewer polyphenols than fruit, some have more than others. Here are the top five vegetables with the highest polyphenol contents:

• globe artichokes: 260 mg per 100 g 

• red chicory: 235 mg per 100 g

• red onion: 168 mg per 100 g

• green chicory: 166 mg per 100 g 

• spinach: 119 mg per 100 g 

10. Soy

Soybeans are a high-protein plant food, and soy-based products can be a great alternative to meat-based products. Soy products that are highest in polyphenols include:

• soy flour: 466 mg per 100 g 

• tempeh: 148 mg per 100 g 

• soy yogurt: 84 mg per 100 g 

• soy tofu: 42 mg per 100 g 

• soy milk: 18 mg per 100 ml

Are there any risks?

When consuming polyphenols as part of whole foods, you are unlikely to experience any ill effects. However, in supplement form, they can contain much higher levels.

Polyphenols can be marketed as nutritional supplements and are minimally regulated in the U.S. Therefore, there is no guarantee of the dosage in polyphenol supplements. 

Some experts suggest that high levels of polyphenols in supplement form might cause:

• interactions with other prescription medications

• carcinogenic effects (potential to cause cancer)

• damage to DNA

• thyroid problems

Summary

There is plenty of choice when it comes to high polyphenol foods. 

Brightly colored berries, spices, nuts, and seeds are a good way to ensure you get a healthy dose of polyphenols in your meals.

Other good sources of polyphenols include olives and extra virgin olive oil, certain vegetables, tea, coffee, soy products, and beans. 

Red wine or dark chocolate — if you stick to them in moderation — may also bring added health benefits to your diet by boosting polyphenols. 

With little regulation on polyphenol supplements, it's best to stick to getting polyphenols from your diet. 

At ZOE, we know that eating a varied diet with plenty of plant foods is the best way to maintain good health. 

However, we also know that everybody is different. If you'd like to find the best foods for your body, start by taking our free quiz today. 

When you join ZOE, we give you a full breakdown of your gut bugs and analyze your personal blood sugar and blood fat responses to food. From this information combined, we can provide tailored nutrition advice to help you achieve your long-term health goals.