Polyphenols are natural compounds found in many plant-based foods and beverages. From berries and dark chocolate to tea and red wine, these substances have been studied for their role in reducing inflammation and protecting against chronic diseases like heart disease, diabetes, and cancer.

While supplements are available, research shows that the health benefits of polyphenols are best gained through food.

Types of Polyphenols

Polyphenols function as antioxidants, helping the body manage inflammation. There are more than 8,000 known types, generally grouped into two categories: flavonoids and non-flavonoids.

Flavonoids

Flavonoids are the most common polyphenols in food and are also used in skincare as natural pigments. One notable example is quercetin, which supports immune health and has antimicrobial properties that may help fight bacteria like Salmonella.

Non-Flavonoids

Phenolic acids are the most well-known non-flavonoids and are found in foods like dark chocolate, tea, and red wine. These compounds have been studied for their potential to reduce inflammation and support treatments for Alzheimer’s disease and high blood pressure.

Health Benefits of Polyphenols

May Support Gut Health

Polyphenols can improve the balance of gut bacteria and reduce the presence of harmful strains like E. coli and Salmonella. They may also reduce gut inflammation and help strengthen the intestinal lining, which is important for preventing inflammatory diseases and immune-related issues.

Improve Cardiovascular Function

Polyphenols may help lower blood pressure, improve blood flow, and reduce the risk of blood clots. They can lower LDL cholesterol and prevent plaque buildup in the arteries, reducing the risk of heart attack and stroke.

Help Prevent and Manage Diabetes

Diets rich in polyphenols are associated with a reduced risk of insulin resistance and type 2 diabetes. Polyphenols can slow starch digestion, help prevent blood sugar spikes, and support insulin-producing cells in the pancreas.

Support Brain Health

Polyphenols may protect against cognitive decline. Green tea and polyphenol-rich spices like those in curry have been linked to better brain function in older adults. They work by reducing oxidative stress and preserving brain cell health.

Lower Cancer Risk

Polyphenols may help reduce the risk of various cancers by protecting cells from damage, supporting immune regulation, and interfering with tumor growth. They’ve been studied for their role in preventing prostate, colon, and breast cancers.

How Much Do You Need?

The Dietary Guidelines for Americans recommend three servings daily of polyphenol-rich vegetables such as legumes, beans, and peas. These foods are emphasized not only for their fiber but also for their antioxidant content.

A registered dietitian can help you find the right balance of polyphenol-rich foods in your diet.

Good Sources of Polyphenols

Many common foods and drinks contain polyphenols, including:

  • Berries (rich in anthocyanins)

  • Tea (especially green and black varieties)

  • Coffee

  • Red wine

  • Legumes

  • Nuts

  • Herbs and spices

For example, 100 grams of berries may contain up to 500 mg of polyphenols, while coffee provides around 280 mg per cup, and red wine offers about 200 mg per glass.

What About Supplements?

Polyphenol supplements such as resveratrol and quercetin are available, but they are not always as effective as consuming polyphenols through food. Some supplements may deliver doses that are too high and could cause unwanted effects.

It’s best to choose supplements that are third-party tested and to consult a healthcare provider before using them.

Risks and Side Effects

While consuming polyphenols through food is generally safe, high-dose supplements can reduce iron absorption, potentially leading to anemia. Excess intake may also cause oxidative stress, the opposite of their intended effect.

Polyphenols can also interfere with digestive enzymes and alter how nutrients are absorbed, which may affect people with food intolerances or digestive disorders.

Possible Drug Interactions

Some polyphenols may interact with medications, including:

  • Anticoagulants (e.g., warfarin, rivaroxaban)

  • Saquinavir

  • Metformin

  • Digoxin

  • Midazolam

  • Sildenafil

  • Statins

  • Beta-blockers

  • Lisinopril

  • Calcium channel blockers

These interactions are mostly from case studies and animal research, so more evidence is needed. If you're on medication, consult your doctor before making dietary changes or starting supplements.

A Quick Recap

Polyphenols are antioxidant compounds found in a variety of plant-based foods and drinks. They play a powerful role in protecting against chronic diseases, supporting digestive and heart health, and improving blood sugar regulation and brain function.

Experts recommend getting polyphenols through a balanced diet rather than supplements. If you're considering adding a supplement, check with your healthcare provider first.