Everything You Need To Know about Polyphenols

Polyphenols are a plant compound in many fruits, veggies, and whole grains. You can also consume polyphenols in beverages like coffee and tea.

Plant-based foods rich in polyphenols can help reduce inflammation and prevent chronic health conditions like diabetes, cancer, and heart disease. Although polyphenols are available as a supplement, the antioxidant benefits are best absorbed through food.

Types

Polyphenols are antioxidants that help the body fight inflammation, which often leads to chronic health conditions.

There are over 8,000 known polyphenols that are divided into two categories: flavonoids and non-flavonoids. Polyphenols can be broken down even further into subgroups like chalcones and isoflavonoids.

Flavonoids

Flavonoids are the most common type of polyphenol found in foods. They have also been used in skincare products as natural dyes.

Quercetin is a popular flavonoid that supports your immune system and protects against diseases. Antimicrobial properties in flavonoids may help prevent bacterial infections like Salmonella enteritidis (salmonella).

Non-Flavonoids

Phenolic acids are the most common type of non-flavonoid and are found in foods and drinks like red wine, tea, and dark chocolate. They work well with nonsteroidal anti-inflammatory drugs (NSAIDs) to prevent inflammation. Phenolic acids have been studied extensively in treatments for Alzheimer's disease (AD) and hypertension (high blood pressure). 

Potential Benefits

Polyphenols are linked with a number of health benefits because of their role as antioxidants. They help reduce free radicals that can damage your cells and cause inflammation. As a result, eating polyphenol-rich foods may help prevent heart disease, cancer, and diabetes, among other benefits.

May Promote Gut Health

Polyphenols encourage the growth of beneficial gut bacteria and prevent the overgrowth of harmful bacteria. Green tea extract rich in polyphenols has been shown to limit the growth of Clostridium difficile, Escherichia coli, and Salmonella typhimurium—bacteria that can cause illness and infection.

Polyphenols may also help decrease inflammation in the gut by altering inflammatory signaling. This can support the health of your intestinal lining. Damage to your intestinal lining can lead to immune system disorders and inflammatory diseases. 

Improve Cardiovascular Health

Another benefit of polyphenols is their ability to promote cardiovascular health. Not only do they act as antioxidants, but they can help expand blood vessels to lower blood pressure and potentially prevent blood clots.

Research suggests polyphenols can help lower low-density lipoprotein (LDL) cholesterol (a lipoprotein that carries fat and protein through the body) and prevent plaque buildup on your artery walls. 

Polyphenols can also inhibit inflammation in your cardiovascular system. Many cardiovascular health conditions are linked to high cholesterol, heart attack, and stroke. Eating polyphenol-rich foods that help counter inflammation benefits your heart health.

Help Prevent and Manage Diabetes

Diets rich in polyphenols have been linked with a lower risk of insulin resistance, prediabetes, and diabetes. Research suggests polyphenols can help slow and reduce the digestion of starches, making it less likely that blood sugar will spike unusually high. 

Polyphenols also reduce inflammation and protect beta cells in your pancreas that produce insulin. Insulin brings sugar into your cells, which gives you the energy you need to make it through the day. Insulin keeps your blood sugar balanced to manage type 2 diabetes. 

Protect Brain Health

Studies show that polyphenols may help prevent neurological conditions like Alzheimer’s and Parkinson’s disease. Green tea is a beverage rich in polyphenols that can help protect your brain health.

In one study, elderly Japanese adults who drank green tea had lower rates of cognitive decline than those who didn’t. Another study found that elderly South Asian participants who regularly consumed curry loaded with polyphenol-rich ingredients had better cognitive function than those who didn’t. 

Neurological conditions increase oxidative stress (having more free radicals than antioxidants in your body) and inflammation, which causes healthy cells to be destroyed sooner. Polyphenols help reduce oxidative stress and inflammation while maintaining the health of brain cells. 

Reduce Your Cancer Risk

Diets rich in polyphenols have been linked with a reduced risk of cancer. Many foods rich in polyphenols also contain other nutrients and vitamins that keep you healthy. There are many ways in which these plant compounds can help prevent against cancer, including:

• Preventing tissue damage
• Regulating your immune system
• Regulating inflammatory markers in the body
• Improving cell signaling
• Stopping cell growth in tumors

Polyphenols have been shown to help prevent different types of cancer, including prostate, colon, and breast cancer.

How Much Do You Need?

The Dietary Guidelines for Americans recommends adults consume three servings per day of vegetables like beans, lentils, and peas.

These are all foods rich in polyphenols, which is part of why they’re emphasized in the USDA’s nutrition recommendations. A nutritionist can help you find ways to balance a good amount of vegetables and fruits in your diet.

Good Sources

Polyphenols are present in many commonly used spices in addition to fruits and vegetables. Foods and beverages rich in polyphenols include:

• Tea
• Wine
• Berries
• Nuts
• Legumes
• Herbs

Berries are an excellent source of polyphenols called anthocyanins, containing up to 500 milligrams (mg) of anthocyanins per 100 grams (g) of berries. Coffee contains up to 280 mg of polyphenols per cup, and a glass of red wine has about 200 mg.

Supplements 

You can purchase polyphenols in supplement form as well. Resveratrol and quercetin are two polyphenols commonly sold as individual supplements.

Research shows that taking polyphenol supplements is less beneficial than eating polyphenol-rich foods. Supplements may have detrimental doses of polyphenols in one capsule. Consider third-party tested supplements to ensure the ingredients listed on the label are accurate. Consult your healthcare provider before consuming polyphenol supplements.

Potential Risks and Side Effects

Taking high doses of polyphenol supplements can potentially cause iron-deficiency anemia since polyphenols can bind to iron and decrease its absorption. Consuming too many polyphenols is unlikely but can increase oxidative stress.

Some studies even show that too many polyphenols could negatively impact cells, which could increase your risk of cancer, diabetes, and neurological conditions. 

Polyphenols can also bind to proteins that make up digestive enzymes and inhibit gut bacteria, leading to difficulty with how your digestive system absorbs nutrients. Having fewer digestive enzymes could worsen symptoms if you have a food intolerance. The inhibition of digestive enzymes can also cause decreased glucose absorption (a sugar found in foods).

Interactions

There are a few medications that may interact with polyphenols. They include:

• Anticoagulant drugs like Coumadin (warfarin) and Xarelto (rivaroxaban)
• Invirase (saquinavir)
• Axpinet (metformin)
• Digitek (digoxin)
• Versed (midazolam)
• Aronix (sildenafil)
• Statins
• Beta-blockers
• Prinivil (lisinopril)
• Calcium channel blockers

Most of these interactions were discovered from individual case studies or animal studies. Therefore, more research and studies are needed to confirm interactions with these medications. Speak with your healthcare provider if you are taking medications and considering changing your diet or taking certain supplements.

A Quick Review

Polyphenols are plant compounds found in many fruits, vegetables, and beverages you consume every day. Polyphenols are antioxidants that help prevent heart disease, diabetes, and other chronic health conditions.

Researchers recommend consuming polyphenols in food rather than as supplements. Consult your healthcare provider before adding polyphenol supplements to your routine.