What Are Polyphenols (And Why You Should Add to Your Diet)

Reviewed by Jeremie Walker, MD, MBA · May 15, 2023
foods rich in polyphenols

When you go food shopping, do you only pay attention to nutrition facts? Or do you take it a step further and look for highly-processed ingredients? Unfortunately, nutrition facts like total sugars and fats don’t tell the whole story. The surest way to know if you are getting a good product is always to read the ingredient list; this will tell you much more about the quality of a product than a plain vanilla “nutrition facts” label. But what’s missing from both are the secondary beneficial compounds our foods contain. For example, not listed is the amount of polyphenols per serving. Polyphenols are potent antioxidants; knowing the best foods rich in polyphenols may improve your health and longevity. 

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What Are Polyphenols?

“Polyphenols are secondary metabolites of plants and are generally involved in defense against ultraviolet radiation or aggression by pathogens,” explains a study in Oxidative Medicine and Cellular Biology. The researchers add that polyphenols are the compounds that provide plant-based foods their bitterness, astringency, color, flavor, odor, and oxidative stability.

In other words, polyphenols protect plants against the sun, bacteria, and fungi and give food its sensory characteristics. But as a secondary metabolite, polyphenols aren’t directly involved in plants’ normal growth, development, or reproduction. 

So what’s the big deal about polyphenols, and why should you care? 

The Health Benefits Of Polyphenols

In the same ways that polyphenols protect plants from oxidative stress from UV rays and pathogens, they also protect us against oxidative stress at the cellular level. 

“Towards the end of the 20th century, … studies … strongly suggested that long-term consumption of diets rich in plant polyphenols offered some protection against the development of cancers, cardiovascular diseases, diabetes, osteoporosis, and neurodegenerative diseases,” says the study in Oxidative Medicine and Cellular Biology. 

So how do polyphenols protect us at the cellular level? The answer: by eliminating a toxic substance in our bodies called reactive oxygen species (ROS). 

Modern life is rife with ROS: Inadvertently breathing gasoline fumes, using synthetic household cleaners, drinking alcohol, smoking, and eating highly-processed food. As a 2022 research review from the Journal of Food Biochemistry explains, ROS are “instigators of several illnesses.”

Not all reactive oxygen species are harbingers of disease. On the contrary, ROS plays a vital part in human biochemistry. Imagine that each of your 37 trillion cells—give or take a trillion—is like a car engine. ROS is the spent fuel. In other words, ROS are produced as a byproduct of cellular metabolism. 

The problem becomes when your body has more ROS than it can neutralize. When this happens, your cell membranes, proteins, and DNA can become damaged, leading to oxidative stress, which can cause numerous chronic diseases, including cancer. 

Polyphenols come to our cellular defense by neutralizing oxidation. This is why they are considered “Strong antioxidants that complement and add to the functions of antioxidant vitamins and enzymes as a defense against oxidative stress caused by excess reactive oxygen species (ROS),” says research in the journal, Nutrients.

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Polyphenol Benefits For Men’s Health

Gentlemen, eat your veggies! 

Excess ROS can lead to inflammation in the blood vessels, which, in turn, can lead to poor blood flow in the penis and erectile dysfunction (ED). The good news is that a 2017 study in Biomedicine & Pharmacotherapy concluded that a diet rich in polyphenols may exert beneficial roles in the management of ED. 

Moreover, “There is substantial epidemiological evidence that a diet high in polyphenol[s] protects against developing cardiovascular disease and type 2 diabetes,” concludes a 2017 study in Nutrition Bulletin. The study also says polyphenols “affect the gut microbiome composition in ways that lead to better human health.”

In other words, eating a whole-food, plant-based diet may not only shrink your waistline but also benefit the trillions of friendly bacteria in your gut. 

Foods High in Polyphenols

So which foods are highest in polyphenols? They are generally highest in fruits, vegetables, chocolate, nuts, herbs, and spices.


Well, not all chocolate. According to the Journal of Food Biochemistry, dark chocolate with a high cocoa content contains a polyphenol (cocoa flavan-3-ols) that “has been associated with a decreased risk of myocardial infarction, stroke, and diabetes.” In general, the Journal says that polyphenols in the diet also help improve lipid profiles, blood pressure, insulin resistance, and systemic inflammation. So, stick with chocolate that is greater than 70% cacao. Plus this reduces the amount of sugar you are consuming.

What are other surprising foods rich in polyphenols? 

Determining the best foods rich in polyphenols isn’t easy, writes a team of Spanish researchers in the journal, Antioxidants. “The separation and determination of polyphenols are difficult tasks due to the high number of polyphenolic molecules and the matrix complexities of different food samples.”

Nonetheless, an intrepid crew of researchers sought to identify the 100 richest dietary sources of polyphenols. Their 2010 findings were published in the European Journal of Clinical Nutrition (EJCN) and summarized on a European natural health website, Freedom of Health. The study is believed to be the first time that the richest dietary sources of polyphenols were identified.

Which food was the polyphenol chart-topper? 

Drum roll, please…


Cloves contain a whopping 15,000 mg of polyphenols per 100 grams. (Obviously, smoking clove cigarettes won’t give you the same polyphenol protection.)

The next highest polyphenol-containing foods include:

  • Peppermint: 11,900 mg
  • Olive leaf: 10,800 mg
  • Star anise: 5,400 mg
  • Brown algae: 4,600 mg
  • Cocoa powder: 3,400 mg
  • Flaxseed meal: 1,500 mg

These foods are probably not on your regular grocery-shopping list. But an easy way to include some of these foods rich in polyphenols is to drink peppermint tea and add flax seeds to your salad or smoothie.

The lowest-ranked polyphenol food in the EJCN study was rosé wine, with only 10 mg of polyphenols per 100 ml of wine (roughly one-third of a glass). So you’d have to get substantially drunk to consume lots of polyphenols. (Obviously, that’s not a healthy way to get your daily dose of polyphenols.)

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High Polyphenol Drinks

So if rosé wine is unimpressive by polyphenol content standards, where does red wine stand? 

Red wine is better than rosé but only contains half the polyphenol content as coffee: 

  • Coffee: 200 mg
  • Red wine: 100 mg
  • Black tea: 100 mg
  • Green tea: 90 mg

Highest Polyphenol Veggies

Mom told you to eat your broccoli. But she should have added the following other high-polyphenol veggies:

  • Artichoke hearts: 300 mg
  • Brussels sprouts: 260 mg
  • Spinach: 110 mg
  • Shallots: 110 mg
  • Broccoli: 100 mg
  • Onions: 75 mg
  • Black beans: 60 mg

High Polyphenol Nuts

Eating nuts not only prevents cravings for high-carb snacks, but several of them also contain high amounts of polyphenols:

  • Chestnuts: 1200 mg
  • Hazelnuts: 495 mg
  • Pecans: 490 mg
  • Almonds: 180 mg
  • Walnuts: 30 mg

Fruits with High Polyphenols

These fruits contain the highest amount of polyphenols, according to the EJCN study:

  • Black elderberry: 1300 mg
  • Blueberries: 850 mg
  • Black currants: 750 mg
  • Strawberries: 250 mg
  • Raspberries: 215 mg
  • Apples: 160 mg

Spice It Up With High Polyphenol Herbs & Spices 

Finally, don’t forget to add herbs and spices to your dishes, including these high-polyphenol ones:

  • Oregano: 2300 mg
  • Celery Seed: 2000 mg
  • Rosemary: 1000 mg
  • Basil: 300 mg
  • Parsley: 280 mg
  • Ginger: 200 mg
  • Cinnamon: 50 mg

The richest sources of polyphenols are dark-colored berries, dark chocolate/cacao, vegetables, olive, and certain seeds and nuts. Try to get a variety of these foods in your diet daily because a polyphenol-rich diet is a critical component of longevity

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