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I'm A Gastroenterologist: Why I Love Polyphenols & How To Get More In Your Diet

Marvin Singh, M.D.
June 7, 2022
Marvin Singh, M.D.
Integrative Gastroenterologist
By Marvin Singh, M.D.
Integrative Gastroenterologist
Marvin Singh, M.D. is an integrative gastroenterologist in San Diego, California. He is trained and board certified in internal medicine and gastroenterology/hepatology.
Olive Oil Over a Salad Bowl
Image by Miquel Llonch / Stocksy
June 7, 2022

You've probably heard about the potential benefits of drinking green tea, adding some olive oil to your diet, and eating your vegetables. Did you know that part of the reason for these recommendations has to do with compounds called polyphenols? Polyphenols are found in lots of plant-based foods and have been found to have numerous benefits for health.

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Why I'm a big proponent of polyphenols.

As an integrative doctor, I'm always looking for the best foods and nutrients that can help my patients live their healthiest lives.

Research has revealed numerous potential benefits of polyphenols, many of which have to do with reducing the risk of chronic disease1 or even supporting gut health. Here are a few noteworthy perks of polyphenols:


Boost mitochondrial health.

Mitochondria are the powerhouses inside our cells, generating most of the energy we need to function. Over time, oxidative stress and age contribute to the decline in mitochondrial function, and our health suffers as a result. Several studies have shown that polyphenols and their metabolites, like Urolithin A, can help repair and rejuvenate mitochondria. 

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Protect against pathogens.

The polyphenols found in green and black tea have been shown to inhibit the growth of different bacteria and viruses such as hepatitis C virus, influenza virus, E. coli, and Salmonella2. There is ongoing research on how polyphenols might influence gut health and potentially promote beneficial bacteria, which helps support a strong immune system, as well.


Promote cardiovascular health.

Studies have shown that intake of polyphenols from foods like tea, nuts, cocoa, grapes, and legumes may reduce the risk of heart attack, as well as help control cholesterol levels and blood pressure3.

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Promote brain health.

Consuming polyphenols from chocolate and green and black tea on a regular basis has been shown to reduce the risk of brain function decline over time. One study also showed potential benefits for the brain of infants, when mothers consumed polyphenol-rich pomegranate juice4.


Help to manage weight.

Studies suggest that the polyphenols in items such as green tea, grapes, and turmeric may help support a healthy weight5.

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Gut support.

Polyphenols' health benefits also come from what happens in our gut when we eat foods containing them. One example is Urolithin A (UA)6, a compound that is produced in the gut when we eat polyphenols from foods like berries, nuts, and pomegranates.

How to get polyphenols in your diet.

The way to increase your polyphenol intake is certainly to consume a variety of plant-source foods. Here are a few to consider:

  • Spices and dried herbs. Try cloves, star anise, peppermint, and Mexican oregano.
  • Red wine. Red wine contains several types of polyphenols, including resveratrol.
  • Black and green tea. These beverages are rich in several types of polyphenols, like catechins.
  • Coffee. The antioxidant polyphenols7 (caffeine, chlorogenic acid, diterpenes, and trigonelline) in coffee have been shown to support brain health.
  • Cocoa powder and chocolate. Rich in several types of polyphenols, mainly catechins and proanthocyanidins. 
  • Olive oil. Extra-virgin olive oil has been shown to have the highest level of polyphenols.
  • Fruits. Berries (especially dark ones) and pomegranates are a particularly good source of polyphenols, in particular anthocyanins and ellagitannins.
  • Vegetables. Black and green olives, globe artichoke heads, red and green chicory, onion, shallot, and spinach are good sources.
  • Grains. Whole grain flours from wheat or rye have several different types of polyphenols. 
  • Nuts and seeds. Flaxseed is rich in lignans, whereas others like chestnut and walnut, hazelnut, pecan nut, and almond contain other types. 
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The takeaway.

Polyphenols are found in a wide variety of plant-source foods. These range from fruits and vegetables to herbs and spices to grains and more. A plant-based diet should generally be rich in various types of polyphenols.

As an M.D., I'm very impressed by the research around polyphenols and strongly advocate for including foods with this plant compound in your diet. That said, more research on humans is necessary to better understand these benefits.

It's also worth noting that I generally recommend going the food route for polyphenols, but supplements can also be beneficial. If you do decide to supplement, be sure to consult with your health care professional first.

Otherwise, go forth and enjoy that coffee and dark chocolate (you're welcome!).

Marvin Singh, M.D. author page.
Marvin Singh, M.D.
Integrative Gastroenterologist

Marvin Singh, M.D is an Integrative Gastroenterologist in San Diego, California, and a Member of the Board and Diplomate of the American Board of Integrative Medicine. He is also trained and board certified in Internal Medicine and Gastroenterology/Hepatology. A graduate of Virginia Commonwealth University School of Medicine, Singh completed his residency training in Internal Medicine at the University of Michigan Health System followed by fellowship training in Gastroenterology at Scripps Clinic Torrey Pines. Singh was trained by Andrew Weil, M.D., a pioneer in the field of integrative medicine, at the Andrew Weil Center for Integrative Medicine.

Singh is currently the Director of Integrative Gastroenterology at the Susan Samueli Integrative Health Institute at UC Irvine. He is also currently a voluntary Assistant Clinical Professor at UCSD in the Department of Family Medicine and Public Health; prior to this, he has been a Clinical Assistant Professor at UCLA and an Assistant Professor of Medicine at Johns Hopkins University. Singh is a member of the American Academy of Anti-Aging Medicine, American College of Lifestyle Medicine, and many other societies. He is actively involved in the American Gastroenterological Association. He is one of the editors of the textbook of Integrative Gastroenterology, 2nd edition (a Weil Series text) and has written several book chapters and articles.

He is dedicated to guiding his clients toward optimal wellness every step of the way, using the most cutting edge technologies to design highly personalized precision based protocols. Towards this end, he founded Precisione Clinic and wrote the book Rescue Your Health to bring the best in preventive medicine to his clients.