64 Foods High in Polyphenols

Polyphenols are a group of compounds found in plant foods that are beneficial for health. They’re naturally found in many plant-based foods like fruits, vegetables, herbs, tea, red wine, and dark chocolate. 

Polyphenols act as antioxidants in the body, meaning they help protect the body and neutralize free radicals that cause damage to cells. Free radicals are highly reactive oxygen molecules produced by normal cell processes and external factors like radiation, air pollution, smoking, and chemical exposure.

Without antioxidants to neutralize free radicals, cells are injured, increasing your risk of health problems like diabetes, heart disease, and cancer.

Keep reading to learn more about the types of polyphenols, health benefits, and potential risks.

Types of Polyphenols

Over 8,000 polyphenols have been discovered. Researchers are still trying to understand exactly how these chemicals impact the human body. 

Flavonoids

Flavonoids make up over half of the currently known polyphenols. The five different types of flavonoids are:

• Anthocyanins
• Flavan-3-ols
• Flavones
• Flavanones
• Flavonols

Flavonoids are found in foods like onions, kale, parsley, tea, red wine, and soybeans. 

Phenolic Acid

Phenolic acid accounts for about 30% of all known polyphenols. The two classes of phenolic acid are hydroxybenzoic acid and hydroxycinnamic acid. Phenolic acid is found in foods like grapes, berries, pomegranates, walnuts, chocolate, coffee, and green tea.

Polyphenolic Amides

Polyphenolic amides have subgroups called capsaicinoids and avenanthramides. Capsaicinoids are found in chili peppers and create the hotness of the pepper. Avenanthramides are found in oats and are believed to help with LDL (low-density lipoprotein, considered “bad”) cholesterol. 

Other Polyphenols

Some polyphenols only have one type, so they account for a smaller portion of these compounds. This group includes polyphenols like:

• Resveratrol is unique to grapes and red wine.
• Ellagic acid is found in berry fruits, such as strawberries and raspberries, and the skin of tree nuts.
• Curcumin is the strong antioxidant that gives the spice turmeric its yellow color.
• Lignans are found in flax, sesame, and some other grains.

Health Benefits of Polyphenols

Most of the health benefits of polyphenols relate to their role as an antioxidant. Antioxidants help protect cells from damage caused by free radicals. So, eating enough antioxidants may help keep cells healthy and lower the risk for some types of diseases.

Researchers are still discovering the health benefits of polyphenols, so more research is needed to understand all the good this compound can provide. Here are the potential health benefits of polyphenols:

Lower Blood Sugar Levels 

Polyphenols may help keep blood sugar levels within a healthy range. Research studies suggest that regularly consuming tea was associated with a lower risk of developing type 2 diabetes. 

In addition, systematic reviews (summary of medical literature) and meta-analyses (examinations of data from many independent studies) suggest that each cup of coffee consumed daily may reduce the risk of developing diabetes by up to 8%.

The anthocyanins found in berries and grapes is another polyphenol associated with lowering the risk and helping manage type 2 diabetes. 

It’s believed these polyphenols help blood sugar levels by:

• Protecting the insulin-producing cells in the pancreas from oxidation by free radicals
• Reducing inflammation
• Preventing starches and simple carbs from being fully digested, which helps prevent blood sugar spikes

Increase Insulin Sensitivity

One of the potential causes of type 2 diabetes is insulin resistance. When you become insulin resistant, cells become less responsive to the hormone insulin, and glucose stays in the bloodstream longer. 

Increasing the cell’s sensitivity to insulin helps bring more glucose in from the blood to keep blood sugar levels within a healthy range. 

A 2017 clinical trial studied the effects of adding over 300 milligrams of polyphenols from strawberries and cranberries to the diet. They found that the polyphenols in strawberries and cranberries effectively increased insulin sensitivity in people with insulin resistance. 

Lower Cancer Risk

Plant-based diets are frequently linked with reducing cancer risk. Polyphenols are likely at least partially responsible.

Research shows polyphenols may reduce the risk of developing some types of cancer, such as:

• Colon cancer
• Prostate cancer
• Epithelial (skin) cancer
• Endometrial (lining of the uterus) cancer
• Breast cancer

Since antioxidants help prevent cell damage, it’s believed polyphenols may lower the risk of cells mutating from damage and becoming cancerous. In addition, polyphenols, like flavonoids, may help increase the expression of apoptotic factors, which may help control tumor cell growth and signal cell death to remove cancerous cells. 

Reduce Inflammation

Chronic inflammation is linked to an increased risk of developing multiple health conditions, like heart disease, diabetes, cancer, and autoimmune diseases.

A 2014 study looked at the effect of the polyphenol lignans on inflammatory markers in the body. The study found the higher the concentration of lignans in the body, the lower the markers of inflammation were.  

Improve Heart Health

Increasing the number of polyphenols in your diet may improve your heart health and lower the risk of cardiovascular diseases. 

Polyphenols may improve multiple risk factors for heart disease, including:

• Lower blood pressure
• Lower LDL cholesterol
• Raise HDL (high-density lipoprotein, considered “good”) cholesterol
• May prevent blood clots

Resveratrol, lignans, and flavonoids have all been linked to improving cardiovascular risk factors. 

However, it is worth noting that not all studies lead to these benefits. For example, resveratrol has not always shown heart-healthy benefits, but this may be because red wine is usually consumed in smaller quantities to avoid drinking too much alcohol.

Boost Brain Function

Research suggests that polyphenols may boost brain function and protect against neurodegenerative diseases like Alzheimer’s disease. 

It’s believed the polyphenol curcumin, found in turmeric, may partially explain why fewer people in India are diagnosed with Alzheimer’s disease, where the spice is regularly used in cooking. Researchers found that older adults who frequently consumed curry (which often contains turmeric) had improved cognitive function than those who rarely ate curry.

Another study found that older adults who drank green tea were less likely to experience cognitive decline than those who drank coffee or black tea.

The benefits to brain function could be related to the antioxidant effects and improvements in blood flow to the brain.  

Improve Digestion

Consuming polyphenols may improve your digestion by promoting the growth of beneficial bacteria while limiting the growth of harmful ones.

For example, research suggests blueberries may promote the growth of the “good” bacterium bifidobacteria. At the same time, green tea may slow the growth of potentially harmful bacteria like Clostridium difficile (C. diff), Escherichia coli (E. coli), and Salmonella typhimurium.

Researchers are just starting to understand the gut microbiome’s role in overall health. The microbiome is the balance of microbes normally present in the digestive tract.

It’s believed the bacteria in the gut play a role in mental health, the immune system, digestion, and more. So, maintaining a healthy balance of good bacteria helps support your overall health. 

Polyphenol-Rich Foods

Polyphenols are found in a wide variety of plant-based foods. Usually, people have heard of the antioxidants in popular foods like dark chocolate, tea, red wine, coffee, and berries. But you may not know polyphenols are in many other common foods, including:

Vegetables

Vegetables high in polyphenols include:

• Broccoli
• Carrots
• Spinach
• Red lettuce
• Onions
• Asparagus
• Artichokes
• Shallots
• Garlic

Fruits

Fruits high in polyphenols include:

• Blueberries
• Strawberries
• Raspberries
• Blackberries
• Cranberries
• Grapes
• Cherries
• Lemon
• Grapefruit
• Oranges
• Pears
• Apples
• Peaches
• Plums
• Pomegranate
• Nectarine
• Apricots
• Olives and olive oil

Grains

Grains high in polyphenols include:

• Oats
• Rye
• Wheat

Nuts and Seeds

Nuts and seeds high in polyphenols include:

• Walnuts
• Almonds
• Flaxseed
• Chia seeds
• Pecans
• Chestnuts
• Hazelnuts

Legumes

Legumes high in polyphenols include:

• Black beans
• White beans
• Soybeans
• Tofu
• Tempeh (made from fermented soybeans)
  

Herbs and Spices

Herbs and spice high in polyphenols include:

• Turmeric
• Cinnamon
• Cumin
• Cloves
• Celery seed
• Basil
• Ginger
• Marjoram
• Parsley
• Peppermint
• Oregano
• Rosemary
• Sage
• Thyme
• Lemon verbena

Other

Other foods and drinks high in polyphenols include:

• Green tea
• Black tea
• Red wine
• Dark chocolate
• Cocoa powder
• Coffee
• Vinegar

Risks and Side Effects

Eating a balance of polyphenol-rich foods is safe for most people. 

However, if you’re considering trying a polyphenol supplement, understand that there could be potential side effects. Supplements aren’t regulated by the Food and Drug Administration (FDA) and supplements tend to deliver higher doses of polyphenols. 

More research is needed to understand the safety and effectiveness of polyphenol supplements. Be sure to talk with your healthcare provider before taking any new supplements. 

In addition, many polyphenol-rich foods are high in other compounds, like fiber. Suddenly increasing your fiber intake can lead to some digestive discomfort, like gas, bloating, and constipation. So, if you’re looking to increase the number of polyphenols in your diet, it may be best to slowly increase them. 

Lectins are another component of plant-based foods. Some sources high in these proteins are raw legumes and whole grains. Because of the lectins' ability to bind to other foods, research suggests, lectins could disrupt digestion, weaken the intestines, and cause nutrient deficiencies. 

If you eat foods with large amounts of lectin and notice symptoms, consider soaking and cooking foods with lectins (such as dried beans and other legumes) because this can decrease the lectins by up to 50%.

Summary

Polyphenols are compounds found in plant-based foods that act as an antioxidant and may lower disease risk. Examples of polyphenols include flavonoids, phenolic acid, polyphenolic amides, resveratrol, curcumin, and lignans.

Potential health benefits include a lower risk of heart disease, diabetes, cancer, inflammation, and cognitive decline. Foods rich in polyphenols include berries, beans, oats, garlic, spinach, and other plant-based foods. 

A Word From Verywell

Polyphenols are available in a wide variety of plant-based foods. So, if you eat a balanced diet full of fruits, vegetables, legumes, whole grains, and cook with a variety of spices, then you can easily consume numerous polyphenols.