Polyphenols Benefits Archives - Health Tips From The Professor

Are Polyphenols Good For Your Heart?

February 17, 2026 by Dr. Steve Chaney

What Are Polyphenols And Why Do We Care?

Author: Dr. Stephen Chaney

Polyphenol-rich foods have taken on a hero status. If we believe the headlines, they:

Reduce the risk of cancer, diabetes, and heart disease.

Enhance gut health.

Reduce inflammation and blood sugar levels.

Fight oxidative stress, which may slow the aging process.

One could write a book on the accuracy of these claims. However, in this article I am just going to focus on the correlation between polyphenol intake and heart disease.

Several recent reviews have suggested that consumption of polyphenol-rich foods is associated with a reduced risk of heart disease.

However, each of those studies has limitations because:

Most of the diet recalls used in these studies relied on food databases that included only a few polyphenols in their database.

Most of the studies did not measure polyphenol levels in blood or urine. That’s important because absorption of polyphenols from the digestive track is often poor.

The study (Y Li et al, BMC Medicine, 23:645, 2025) I will review in today’s issue of “Health Tips From the Professor” is a significant improvement over previous studies because it relies on a database with over 500 polyphenols for its diet analysis and it measures polyphenol metabolites in the urine to confirm the data obtained from the dietary recalls.

But first let’s discuss what polyphenols are and why they are important.

What Are Polyphenols And Why Do We Care?

Simply put, a phenol is a ring of carbon atoms with at least one OH group attached. Polyphenols consist of multiple ring structures. Resveratrol, shown on the left, is an example of a polyphenol structure.

However, that downplays the complexity of polyphenols. There are over 8,000 polyphenols structures found in plants and over 500 in common foods. And each of these structures has unique chemical and biological properties.

However, there are also some commonalities.

In fruits and vegetables, polyphenols are most commonly found in the skins or peels and protect them from UV light, pests, and disease pathogens.

In our bodies polyphenols:

Improve blood flow and reduce blood pressure.

Lower LDL (bad) cholesterol.

Improve insulin sensitivity.

Are antioxidants that neutralize free radicals and reduce inflammation.

Finally, most polyphenols are colored, which is why we are told to eat a variety of colorful fruits and vegetables.

How Was This Study Done?

The study included 3110 participants from the TwinsUK registry who completed the EPIC-Norfolk Food Frequency Questionnaire. The participants were predominantly female (96.7%) and white (99%), with an average age of 52 years and an average BMI of 25.4%.

The TwinsUK registry aspect of the study was not important. Twin information was not utilized in the data analysis.

However, the EPIC-Norfolk Food Frequency Question was important. The EPIC Food Frequency database is particularly robust, and it is designed to be country specific. The EPIC-Norfolk version was designed to include 130 commonly eaten foods in the Norfolk area of England where the study was centered.

The polyphenol content of the foods in the EPIC-Norfolk Food Frequency Questionnaire was calculated using the most recent version of the Phenol-Explorer database which measures the amounts of 500 different polyphenols in 400 foods.

The investigators then developed a polyphenol-rich dietary score, PPS, based on the relative intake of the top 20 polyphenol-rich foods in the English diet.

To be clear, in the dietary portion of the study, the investigators measured:

- The amount of 500 individual polyphenols in each participant’s diet.

- And the overall polyphenol dietary score (PPS) of each participant.

The investigators also measured cardiovascular risk factors (blood pressure, total cholesterol, HDL cholesterol, and LDL cholesterol) for each participant.

These data were used to calculate an ASCVD risk score and a HeartScore for each participant. These are two of the leading risk estimators for heart disease.

Finally, the investigators measured the content of polyphenol metabolites in the urine of a subset of 200 participants chosen at random.

These data were meant to correct for absorption of polyphenols from the intestine and confirm associations seen from the dietary data.

Are Polyphenols Good For The Heart?

Prescription for good health overhead with stethoscope, healthy fresh food and exercise equipment, with copy space.

Here is what the study showed:

Participants with higher PPS scores (a diet rich in polyphenol-containing foods) had significantly lower risk of heart disease by both the ASCVD risk score and the HeartScore.

When the investigators looked at individual classes of polyphenols, high intake of flavonoids and phenolic acids appeared to be particularly beneficial, as did a high intake of the stilbenoid, resveratrol.

Measurement of polyphenol metabolites in the urine confirmed this association.

Consuming a diverse array of polyphenol-rich foods (a high PPS score) was a better predictor of heart health than eating any individual food or class of polyphenols alone.

The authors concluded, “Longitudinal data indicate that higher adherence to polyphenol-rich diets is associated with lower long-term cardiovascular risk in predominately middle-aged women.

The PPS dietary score, reflecting adherence to polyphenol-rich diets, showed the strongest association with CVD risk compared to individual polyphenol intakes or specific polyphenol-rich food sources.

The cardioprotective effects of flavonoids and phenolic acids, estimated from the EPIC-Norfolk FFQ, were further confirmed through urinary metabolite analysis within the same polyphenol classes.”

What Does This Study Mean For You?

This study is consistent with several previous studies showing that high intact of polyphenol-rich foods correlates with a reduced risk of heart disease. However, this study is important because it is the strongest study to date because:

It uses a very robust database for estimating both the total polyphenol content of foods and the amount of 500 different polyphenols in each food.

It includes an analysis of polyphenol metabolites in the urine to account for differences in absorption of polyphenols from the gut and to confirm the asssociations between polyphenol intake and heart disease risk based on dietary data.

But you are probably wondering, “How do I use this information I don’t know the polyphenol content of the foods I eat.”

There are two ways you could think about the data.

#1: You could ask, “What should I eat to get plenty of flavonoids, phenolic acids, and resveratrol in my diet?” That’s a fairly easy question to answer.

The top food sources of favonoids are berries (blueberries, strawberries), tea (green and black), dark chocolate/cocoa, red wine, citrus fruits (oranges, lemons), leafy greens, onions, and soybeans.

The top food sources of phenolic acids are coffee, berries (especially chokeberries and blueberries), herbs/spices (cloves, peppermint), cocoa, and whole grains.

The top food sources of resveratrol are red grapes (especially the skin), blueberries, raspberries, mulberries, peanuts, dark chocolate, and red wine.

#2: You could ask, “What would a polyphenol-rich diet look like for me?”

You should start with the oft-repeated recommendation to eat a variety of highly colored fruits and vegetables.

Then add foods like tea, coffee, dark chocolate, and others from the list above.

My final two recommendations are:

Don’t focus on just one or two polyphenol-rich foods. Remember that the study showed that eating a wide variety of polyphenol-rich foods was more beneficial than individual foods or polyphenols.

This applies to whole foods only. The dyes used to add color to processed foods don’t count.

The Bottom Line

Several previous studies have shown that high intact of polyphenol-rich foods correlates with a reduced risk of heart disease. However, those studies all had limitations. In this issue of Health Tips From the Professor I discuss the strongest study on this subject to date. The study showed:

Participants with higher PPS scores (a diet rich in polyphenol-containing foods) had significantly lower risk of heart disease by both the ASCVD risk score and the HeartScore.

When the investigators looked at individual classes of polyphenols, high intake of flavonoids and phenolic acids appeared to be particularly beneficial, as did a high intake of the stilbenoid, resveratrol.

Measurement of polyphenol metabolites in the urine confirmed this association.

Consuming a diverse array of polyphenol-rich foods (a high PPS score) was a better predictor of heart health than eating any individual food or class of polyphenols alone.

For more information on this study and what it means for you, read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease.

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My posts and “Health Tips From the Professor” articles carefully avoid claims about any brand of supplement or manufacturer of supplements. However, I am often asked by representatives of supplement companies if they can share them with their customers.

My answer is, “Yes, as long as you share only the article without any additions or alterations. In particular, you should avoid adding any mention of your company or your company’s products. If you were to do that, you could be making what the FTC and FDA consider a “misleading health claim” that could result in legal action against you and the company you represent.

For more detail about FTC regulations for health claims, see this link.

https://www.ftc.gov/business-guidance/resources/health-products-compliance-guidance

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About The Author

Dr. Chaney has a BS in Chemistry from Duke University and a PhD in Biochemistry from UCLA. He is Professor Emeritus from the University of North Carolina where he taught biochemistry and nutrition to medical and dental students for 40 years. Dr. Chaney won numerous teaching awards at UNC, including the Academy of Educators “Excellence in Teaching Lifetime Achievement Award”. Dr Chaney also ran an active cancer research program at UNC and published over 100 scientific articles and reviews in peer-reviewed scientific journals. In addition, he authored two chapters on nutrition in one of the leading Biochemistry textbooks for medical students.

Since retiring from the University of North Carolina, he has been writing a weekly health blog called “Health Tips From the Professor”. He has also written two best-selling books, “Slaying the Food Myths” and “Slaying the Supplement Myths”. And most recently he has created an online lifestyle change course, “Create Your Personal Health Zone”. For more information visit https://chaneyhealth.com.

For the past 53 years Dr. Chaney and his wife Suzanne have been helping people improve their health holistically through a combination of good diet, exercise, weight control and appropriate supplementation.

Do Muscadine Polyphenols Reduce Skin Aging?

August 8, 2023 by Dr. Steve Chaney

What Does This Study Mean For You?

Author: Dr. Stephen Chaney

Normally, I don’t discuss results from pilot studies. I wait until larger studies have been published in peer reviewed journals. But I thought this study might be of interest to you.

Polyphenols from muscadine grapes and muscadine wine have been reported to reduce cellular aging. So, scientists from the University of Florida decided to do a pilot study asking whether muscadine polyphenols in the diet might improve signs of an aging skin. They reported their results in a poster (L Christman and L Gu, Dealcoholized Muscadine Wine Improved Skin Health, Reduced Oxidative Stress, and Inflammation in Women in a Randomized Controlled Trial, July 24, 2023) presented at the American Society for Nutrition’s NUTRITION 2023 meeting.

They enrolled 17 healthy women ages 40-67 to participate in a randomized, single-blinded, placebo controlled, cross-over study. Simply put, that means:

The study started with a 7-day “run-in period” in which their diet was standardized.

Then they were asked to drink 10 ounces/day of dealcoholized muscadine wine or a placebo drink for 6 weeks. Since participants did not know which beverage they were given, this is the “single-blind” part of the experimental design.

This was followed by a 21-day “wash-out” period to allow muscadine polyphenols to be flushed out of their system.

They then were switched to the opposite beverage for an additional 6 weeks. This was the “cross-over” portion of the experimental design.

Their skin conditions and blood markers of inflammation and oxidative stress were measured at the start (baseline) and end of each 6-week portion of the study.

When compared to both baseline and placebo, the dealcoholized muscadine wine significantly improved:

Skin elasticity, which prevents the skin from sagging as it ages.

Retention of moisture at the skin surface, which indicates the skin is providing a more effective barrier against aging.

Skin smoothness.

Blood glutathione peroxidase activity, a measure of antioxidant protection.

The authors concluded, “This randomized controlled trial demonstrated that consumption of polyphenol-rich dealcoholized muscadine wine improved skin conditions associated with aging. This is likely due to decreases in inflammation and oxidative stress.”

What Does This Study Mean For You?

As for what this study means for you, I have two words, “Stay tuned”.

On the plus side, while muscadine polyphenols have been shown to reduce markers of skin aging when applied to the skin, this is the first study to suggest those same benefits may be seen from the inside out – i.e., from dietary muscadine polyphenols.

On the minus side, this is a pilot study. Pilot studies are meant to test hypotheses to see whether there is enough evidence to justify larger studies. In the words of the authors, “…repeating this study with a larger and more diverse group of people would help to confirm and strengthen the findings going forward.”

So, stay tuned. When the results of larger studies have been published in peer-reviewed scientific journals, I will give you an update.

The Bottom Line

Scientists at the University of Florida recently did a pilot study to see whether muscadine polyphenols in the diet might improve signs of an aging skin. When compared to a placebo, dealcoholized muscadine wine significantly improved skin elasticity, moisture retention, and smoothness. It also increased blood glutathione peroxidase activity, a measure of antioxidant protection.

So, stay tuned. When the results of larger studies have been published in peer-reviewed scientific journals, I will give you an update.

For more information on this study read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease.

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For more detail about FTC regulations for health claims, see this link.

https://www.ftc.gov/business-guidance/resources/health-products-compliance-guidance

Maximizing Polyphenols Benefits

April 30, 2019 by Dr. Steve Chaney

The Symbiotic Relationship Between Gut Bacteria And Polyphenols

Author: Dr. Stephen Chaney

How to maximize polyphenols benefits?

Polyphenols are ubiquitous in the plant world. There are many kinds of polyphenols, and they are found in a wide variety of fruits, vegetables, whole grains, and legumes. You probably already know that polyphenols are also found in tea, coffee, chocolate, and many herbs and spices.

Polyphenols are thought to have a wide array of health benefits. For example, the polyphenols in grapes are thought to:

Reduce inflammation.
Reduce the risk of heart disease, cancer, and diabetes.
Prevent or delay the onset of neurodegenerative diseases like Alzheimer’s.

The amazing thing is that polyphenols are effective at all. They are poorly absorbed and rapidly eliminated from the circulation. For example, resveratrol, a polyphenol found in red grapes, only stays in the circulation for a few hours.

In the case of resveratrol, we know that, during its brief time in our bodies, it turns on “anti-aging” genes that control things like inflammation, protection against free radical damage, cholesterol metabolism, blood sugar control, and blood pressure. We are less certain how other polyphenols exert their beneficial effects during the short time they are in our bodies.

When we scientists are facing a problem like this, it stimulates our creative thinking. We start asking questions like:

Can we improve the absorption of beneficial polyphenols into the bloodstream?
Would that improve their effectiveness and health benefits?

A recent review (D Zhao et al, Critical Reviews In Food Science and Nutrition: Jan 7, 1-29, 2019) looked at the first question. It summarized the most promising strategies for improving the absorption of grape polyphenols. We don’t yet know the answer to the second question.

Before I discuss the most promising strategies, the professor in me wants to cover Polyphenols 101, something I call “The Symbiotic Relationship Between Gut Bacteria and Polyphenols”.

The Symbiotic Relationship Between Gut Bacteria and Polyphenols

The world of polyphenols is complex. For example:

Resveratrol is the best-known and best-studied polyphenol in grapes, but there are dozens of other beneficial polyphenols in grapes.
Each of these polyphenols have unique metabolic pathways and unique health benefits.
Each variety of grapes has a unique blend of polyphenols.
Each polyphenol is metabolized differently by our gut bacteria and by enzymes in our body.
You start with dozens of polyphenols in the grape and end up with hundreds of metabolites in the body.
Some of these metabolites are better absorbed. Some are not absorbed at all. Some of these metabolites are highly active. Others are inactive. The possibilities are endless.

As if that weren’t enough, there are two more complexities to factor into the equation.

There is a symbiotic relationship between gut bacteria and polyphenols.
Our gut bacteria influence the metabolism and absorption of the polyphenols in our diet.
The polyphenols we consume influence the population of bacteria in our gut.
The kinds of fiber we consume influence which bacteria populate our gut, and that, in turn, influences how we metabolize the polyphenols we consume.

Faced with this level of complexity, there have been two types of approaches to improving the absorption of polyphenols.

The pharmaceutical approach, which tries to bypass the complexities of polyphenol absorption.
The natural approach, which tries to optimize the complexities of polyphenol absorption.

The review (D Zhao et al, Critical Reviews In Food Science and Nutrition: Jan 7, 1-29, 2019) gives examples of each type of approach, which I will discuss below.

Maximizing Polyphenols Benefits

Pharmaceutical Approaches: These are approaches designed to bypass the complexities of polyphenol absorption. The authors considered the following two strategies to have the most probability of success:

Chemical alteration of polyphenol structure. This is a classical pharmaceutical strategy. You start with naturally occurring compound that has medicinal benefit. Then you chemically modify it in multiple ways until you find a chemical modification that is efficiently absorbed and is stable in the circulation. There are two drawbacks to this approach:
You have created a new compound with its own properties. You have created a drug that needs to be tested for safety and efficacy. Resveratrol, for example, offers a cautionary tale. A drug company modified it. The modified form was efficiently absorbed and was stable in the bloodstream. They thought they had created the perfect drug. Unfortunately, when they tested it, they found out it was toxic.
Even if you did optimize safety and efficacy of the polyphenol, you have only optimized one polyphenol out of the dozens found in the real food.
Incorporate the polyphenol into nanoparticles that are absorbed so efficiently by the intestine that they effectively bypass metabolism by gut bacteria. This is a strategy currently being explored by drug companies to improve the efficacy of poorly absorbed drugs. Even if successful, this approach has the same type of drawbacks.
This is a relatively new technology. There are some concerns it may not be safe.
Foods have dozens of polyphenols. A nanoparticle strategy may improve the absorption of one or two polyphenols, but it is unlikely to replace the real food.

Natural Approaches: These approaches are designed to optimize the complexities of polyphenol absorption.

Develop a probiotic supplement containing bacteria that improve polyphenol uptake. There is some promising research in this area.
However, when we talk about gut bacteria, the phrase “It takes a village” takes on a whole new meaning. There may be dozens of bacteria involved in improving polyphenol uptake, not just one or two. The probiotic supplement may need to be a horse pill
Add fiber to the diet to support the growth of the gut bacteria that enhance the absorption of polyphenols. This may be the most promising strategy.
Studies have already shown that pectin and similar non-digestible polysaccharides improve the absorption of polyphenols found in grapes and many other foods.
While grapes are low in pectin, other fruits (most notably apples, peaches, citrus fruit, apricots, and plums) are high in pectin. Legumes and some vegetables are also high in pectin. The only reason you don’t find them on most lists of high pectin foods is these lists are for foods that have enough pectin to make good jams without any added pectin. Legumes and vegetables are also high in insoluble fibers, which interfere with the gelling required for a good jam. Besides, kale or pea jam are probably not high on anyone’s list of favorite jams.
The best thing about this approach is that it is completely natural. It involves eating a plant-based diet with fruits, vegetables whole grains, and legumes, something humans have been doing for thousands of years. This a diet chock full of beneficial polyphenols and the fiber needed to support the gut bacteria that help us utilize those polyphenols. There are no side effects. There is no danger associated with this approach.

Once again, Mother Nature knows best.

Addendum

While writing this article I happened to read “The People’s Pharmacy” column by Joe & Terry Graedon in our local paper (Yes, I still read a physical newspaper). They were talking about combining pectin with grape juice to relieve arthritis pain. Some of the polyphenols in grape juice have anti-inflammatory effects. But, grape juice alone is not very effective at relieving arthritis pain. However, it turns out that pectin plus grape juice, something called “purple pectin remedy,” is a home remedy for arthritis pain relief that has been around since the 1940s. They did not discuss a mechanism, but now we know how it works.

Note: I suppose if you are getting your grape polyphenols from grape juice, wine, or some other liquid source, you could stir in some pectin to improve their absorption. However, my recommendation would be to consume a primarily plant-based diet with a variety of fruits, vegetables, whole grains, and legumes along with your liquid polyphenol source.

The Bottom Line

Resveratrol and other polyphenols found in grapes have many health benefits. However, these polyphenols are poorly absorbed. A recent review described ongoing research into approaches for improving the absorption of grape polyphenols

I discuss the various approaches that are being studied in my article above. Some are pharmaceutical approaches that involve structural alterations to the polyphenol or nanoparticle delivery systems to improve absorption. Others involve probiotics that contain bacterial strains that enhance polyphenol absorption. Each of these approaches have limitations, or dangers, or both.

The most promising approach was to simply add fiber to the diet to support the growth of the gut bacteria that enhance the absorption of polyphenols.

Studies have already shown that pectin and similar non-digestible polysaccharides improve the absorption of polyphenols found in grapes and many other foods.
While grapes are low in pectin, other fruits (most notably Apples, peaches, citrus fruit (especially the skin), apricots, and plums) are high in pectin. Legumes and some vegetables are also high in pectin. The only reason you don’t find them on most lists of high pectin foods is these lists are for foods that have enough pectin to make good jams without any added pectin. Legumes and vegetables are also high in insoluble fibers, which interfere with the gelling required for a good jam. Besides, kale or pea jam are probably not high on anyone’s list of favorite jams.
The best thing about this approach is that it is completely natural. It involves eating a plant-based diet with fruits, vegetables whole grains, and legumes, something humans have been doing for thousands of years. This a diet chock full of beneficial polyphenols and the fiber needed to support the gut bacteria that help us utilize those polyphenols. There are no side effects. There is no danger associated with this approach.

Once again, Mother Nature knows best.

Note: If you are getting your grape polyphenols from grape juice, wine, or some other liquid source, you could stir in some pectin to improve their absorption. However, my recommendation would be to consume a primarily plant-based diet with a variety of fruits, vegetables, whole grains, and legumes along with your liquid polyphenol source.

For more details read the article above. You will also find an interesting story about the “purple pectin remedy”.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.