Polyphenols are rockstars of nutrition. Why? Because they’re antioxidants. Antioxidants protect your body from free radicals, which yes, sounds like a new wave band name, but are actually molecules that damage your cells and can even damage your DNA . That damage is known to be responsible for aging-related health conditions like high blood pressure and high cholesterol.
When you think about it, antioxidants are the real rockstars here. But these specific antioxidants are special. Studies have shown that in addition to those antioxidant properties, polyphenols can help with inflammation, allergies, artery health, blood flow, and protect your genes from mutation .
Polyphenols In Your Food
Polyphenols are the most abundant of all antioxidants. You probably already eat about 1 gram of polyphenols every day. That’s significantly more than any other kind of antioxidant that’s in your diet .
Not only are there tons of foods that contain polyphenols, there are also tons of polyphenols in those foods.
Here is a table with the top 100 most polyphenol-rich foods. Think about that. There are enough polyphenol-rich foods in the world to have a list of the top 100. That’s a lot of food!
And here are 10 of the foods you’re most likely to already have in your kitchen:
|Food Group||Amount of Polyphenols*|
|Cocoa powder||Cocoa products||3,448mg|
|Green tea||Non-alcoholic beverages||89mg|
|Extra virgin olive oil||Oils||62mg|
|White wine||Alcoholic beverages||
|*per 100g or ml of food or drink, respectively|
Now, let’s go over all their health benefits from polyphenols and other nutrients.
Cocoa from Theobroma cacao tree contains a huge amount of the polyphenol flavonoid . A lot of research has been done on cocoa over the past 20 years, finding that it can reduce inflammation and is connected to decreased risk of heart disease .
Catechins are one of the most important antioxidants in green tea. They’re part of the flavonoid family of polyphenols and help prevent oxidative stress caused by environmental factors, like UV rays and toxic fumes in the air. One catechin in particular, called EGCG, may be able to help counteract the negative effects of the “Western diet,” e.g. a diet high in sugar and fat and low in beneficial nutrients .
Most olives turn black when they are fully ripe. As olives ripen, their oleuropein levels fall and when they’re fermented, oleuropein virtually disappears. The good news is that other polyphenols, like hydroxytyrosol, increase significantly, and that their health benefits are the same as that of green olives .
This fruit belongs to the same group as the aforementioned olives. They offer a number of vitamins, minerals, and nutrients, like folate, vitamins A, C, K, B1, B2, B3, B6, iron, calcium, and fiber. A few amazing health benefits plums and prunes (their dried counterparts) can have are relief from indigestion, improved cellular health, and boosted immunity . The most potent polyphenols in plums are hydroxycinnamic acids, which are a type of phenolic acid .
Cocoa is responsible for the polyphenol content in chocolate, but don’t go stocking up on Hershey bars just yet. A 2014 study found that chocolate with higher cocoa content can improve blood flow in patients with peripheral artery disease (PAD) better than chocolate with a lower cocoa content . Milk chocolate doesn’t have a high polyphenol count compared to plain cocoa powder and with a high sugar, fat, and calorie count, it isn’t something you should include regularly in your diet.
Apples are a great source of antioxidants because both the flesh and skin of the fruit contain polyphenols. Flavonoids and phenolic acids are the two polyphenol groups that make up the majority of the antioxidants in apples and apple juice . Whole apples have even been shown to improve cholesterol levels .
Adding just a few tablespoons of extra virgin olive oil (EVOO) to your diet can have significant health benefits. Studies have shown that polyphenols in EVOO can help combat some symptoms of aging, like cognitive decline, skin health, and protects against oxidative stress.
Extra virgin olive oil has more health benefits, beyond those provided by polyphenols. Aside from its antioxidant benefits, extra virgin olive oil has been shown to benefit the brain, improve skin health, and support good bone health .
These tubers are one of the richest food sources of antioxidants available. Red and purple potatoes contain the most polyphenols, but one small problem is that a lot of these antioxidants are reduced when potatoes are cooked. One way to minimize that reduction is the way you cook these tubers. Research shows that boiling potatoes affects polyphenol content the least and baking them has the most severe effect .
Red wine is like the Regina George of polyphenol foods and beverages. It’s constantly being praised (for its health benefits) by some and disparaged by others. Drinking a moderate amount of wine—5 ounces is one serving—has been linked to a 30-50% reduced risk for heart disease. Resveratrol is the big-name polyphenol in red wine and is linked to a reduced risk of cardiovascular decline that comes with age .
If red wine is Regina George, then white wine is the overshadowed little sister. Wine is made through processing grapes, which have a lot of polyphenols in their skin and seeds. White wine is made without the skin or seeds, so it contains far fewer polyphenols than red wine, which involves the entire grape.
Different Kinds of Polyphenols
There are four main groups of polyphenols: phenolic acids, flavonoids, stilbenes, and lignans. Each is a naturally occurring compound, usually found in fruits, vegetables, cereals, and drinks. There is still a lot of research to be done to determine what kind of specific health benefits each of these polyphenol have, but they’re all antioxidants, so you really can’t go wrong.
The highest concentration of phenolic acids can be found in the seeds and skin of fruits and the leaves of vegetables . Some foods rich with phenolic acids are mangoes, apples, cherries, onions, coffee, and red wine. These polyphenols are derived either from benzoic acid or cinnamic acid .
This group is responsible for the bright colors of fruits, flowers, and leaves. Foods with flavonoids include tea, citrus fruits like orange, lime, grapefruit, and lemon, berries such as blueberries, blackberries, and elderberries, apples, and legumes like beans, peas, and lentils . There are 6 different sub-groups of flavonoids:
- Flavanols (commonly referred to as flavan-3-ols)
Among those subclasses are more than 4,000 varieties of flavonoids that have been identified. Given all this information, it should come as no surprise that flavonoids are the most-studied of all polyphenol groups .
These polyphenols aren’t as common as others, and there are only two that you may have possibly heard of: resveratrol and pterostilbene. If you’ve heard of the latter, you’re probably already a polyphenol expert, but the former, resveratrol, is fairly well-known because it’s found in red wine. Resveratrol can also be found in grape skin, blueberries, peanuts, and cranberries. The other stilbene, pterostilbene can be found in blueberries and grapes .
Of all the lignan-rich foods, flaxseeds have the highest concentration of this polyphenol. Like other polyphenols, lignans can be found in seeds, whole grains, legumes, fruits, and vegetables .
With all of the research being done on polyphenols, we still don’t know much about their unique health benefits, so there’s no need to worry about getting the right amount of each polyphenol group. On average, people get from 0.1 to 1 gram of polyphenols every day. Without a recommended daily serving or limit, you’re free to consume as many polyphenols as you want.
With so many polyphenol-rich foods and beverages to choose from, there are bound to be some that are perfect for you, no matter what your diet restrictions or preferences are.
Polyphenols and Gut Health
Probiotics and prebiotics are the two P words that have staked their claim in gut health, but polyphenols shouldn’t be left out. Health benefits of polyphenols are largely focused on the heart, but they play a role in gut health as well.
Polyphenols seem to act like prebiotics, in that they act as fuel for healthy bacteria living in your gut. A lot of research has been done on the effects of polyphenols from tea in specific and shown that with polyphenols repressed the growth of certain bacteria strains and had little effect on others .
Factors that Influence Polyphenols
Polyphenol-rich foods are not created equal. Sun exposure, soil, and rainfall each play a role in how many polyphenols are in different foods. Blueberries grown in one field with a lot of rain and sunshine could easily have far more or fewer polyphenols than the same blueberries grown in a different field.
Other factors include:
Storage of Polyphenols
Believe it or not, the way foods are stored can also affect their polyphenol content. The quality of polyphenols will stay the same, but, depending on how these foods are stored, the quantity of polyphenols may change. For some foods, like tea, this is actually beneficial. But for others, like fruit, it’s not.
Cold storage, on the other hand, allows for little change in polyphenol content. Have you noticed how long produce like apples and onions last when they’re stored in the fridge? The cold temperature is responsible for this.
Ripeness of the Source
Phenolic acid decreases when fruit ripens, while anthocyanidins (a type of flavonoid) actually increase. Ripeness loops back to storage, where open-air storage affects polyphenol content, and cold storage only does a little.
It makes sense, then, that cooking at high temperatures changes polyphenols in food. This isn’t exactly news, or unique to polyphenols. Pretty much any way you prepare food will alter its nutritional value . One study, done with onions and tomatoes, found that the two foods lost 75-80% of their quercetin (flavonoid) content when they were boiled, 65% when microwaved, and 30% after frying.
Another study, done in 2014, showed that steaming sweet potato leaves increased their polyphenol content and antioxidant activity–not that anyone lives and dies for sweet potato leaves, but it’s safe to assume that these cooking methods have similar effects on other leafy veggies .
Since there’s no way to determine the polyphenol content of food at the market, it’s best to go by the average polyphenol count as laid out in the polyphenol table that’s linked earlier in the article, and store and cook these polyphenol-rich foods to maximize their nutritional quality.
Are Polyphenols Right For You?
You really can’t go wrong with polyphenols. If polyphenol-rich foods are already included in your diet, you can add more to maximize their health benefits. If not, adding one or two to your daily regimen is an easy way to start. From heart health to gut health to everyday oxidative stress, you’re bound to benefit in one way or another.