Exercise, Muscle Recovery & Tart Cherries: What Does the Research Say?

Fruits contain thousands of naturally occurring compounds. Among the most widely studied are a diverse group of plant compounds commonly referred to as polyphenols.

Polyphenols occur throughout the plant kingdom and are found in foods such as fruits, vegetables, grains, tea, coffee, cocoa, herbs, and other plant-based foods.

Tart cherries, wild blueberries, aronia berries, cranberries, grapes, pomegranates, and many other deeply colored fruits contain mixtures of different polyphenols.

But “polyphenols” does not describe one single substance—and the presence of polyphenols in a food does not automatically establish a particular effect in the human body.

Understanding what polyphenols are, how researchers classify them, and why different fruits contain different mixtures of these compounds provides a useful foundation for interpreting fruit and nutrition research.

The Short Answer

Polyphenols are a large and chemically diverse group of naturally occurring plant compounds.

The term includes numerous compounds found in fruits and other plant foods. Depending on the classification system being used, major groups commonly discussed include flavonoids, phenolic acids, stilbenes, and lignans. Flavonoids can be divided further into subclasses that include anthocyanins, flavonols, flavanones, flavones, and flavan-3-ols.

This means that saying a fruit “contains polyphenols” provides only part of the picture. Two fruits can contain very different combinations and amounts of individual phenolic compounds.

Researchers study polyphenols for many reasons, including their chemistry, metabolism, bioavailability, interactions with biological systems, and their possible relationships with different aspects of human nutrition and health.

However, results involving one isolated compound, one food, or one preparation should not automatically be attributed to every polyphenol-rich fruit or product.

Throughout this guide, we'll distinguish between what these compounds are, where they occur, and what scientific research has actually investigated.

What Are Polyphenols?

Polyphenols are part of the much larger family of naturally occurring compounds produced by plants.

Chemically, the terminology is more complicated than the name might suggest. Polyphenols and related phenolic compounds are often classified according to characteristics such as the number and arrangement of phenolic rings and the structural elements connecting them. Scientific publications do not always use exactly the same classification system.

In nutrition research, the term polyphenols is often used broadly when discussing families of phenolic compounds occurring in plant foods.

Commonly discussed groups include:

• Flavonoids
• Phenolic acids
• Stilbenes
• Lignans

Some classification systems also discuss tannins and other phenolic compounds separately or as additional categories.

Within these broad groups are many individual compounds. For example, anthocyanins are flavonoids, while compounds such as caffeic acid and ferulic acid are generally classified as phenolic acids. Resveratrol belongs to the stilbene group.

These distinctions matter because different compounds can differ substantially in their chemical properties, food sources, metabolism, and bioavailability.

For that reason, FruitFast does not treat the terms polyphenol, flavonoid, anthocyanin, and antioxidant as interchangeable.

Why Do Plants Produce Polyphenols?

Polyphenols are produced by plants as part of their normal growth, development, and interactions with the environment.

In plants, phenolic compounds can perform a variety of functions. Depending on the compound and plant species, they may contribute to color, pigmentation, structural characteristics, interactions with microorganisms, and responses to environmental conditions.

Some polyphenols are especially noticeable because they influence the appearance of fruits.

Anthocyanins, for example, contribute to many of the red, purple, and blue colors found in fruits such as tart cherries, wild blueberries, aronia berries, black currants, cranberries, raspberries, and grapes.

Other phenolic compounds may be present without producing such obvious visual characteristics.

The amount and mixture of polyphenols in a fruit can also change with factors such as:

• plant variety or cultivar;
• growing conditions;
• maturity and ripeness;
• environmental conditions;
• harvesting and storage; and
• processing.

This means that even two samples of the same type of fruit may not necessarily contain identical amounts of every polyphenol.

That variability becomes particularly important when researchers compare foods, juices, concentrates, extracts, powders, and supplements.

Major Types of Polyphenols Found in Foods

Polyphenols include many individual compounds, but grouping them into broader families makes the subject easier to understand.

The classification below provides a practical overview commonly used in food and nutrition research.

Group	Examples	Food Sources Commonly Associated With the Group
Flavonoids	Anthocyanins, flavonols, flavanones, flavones, flavan-3-ols	Berries, cherries, grapes, citrus, tea and many other plant foods
Phenolic Acids	Caffeic acid, ferulic acid, p-coumaric acid	Fruits, vegetables, grains, coffee and other plant foods
Stilbenes	Resveratrol	Grapes and certain other plant foods
Lignans	Secoisolariciresinol and related compounds	Seeds, grains and various plant foods

Flavonoids

Flavonoids are one of the largest and most widely studied groups of polyphenols.

The flavonoid family itself contains several subclasses, including anthocyanins, flavonols, flavanones, flavones, and flavan-3-ols.

Different fruits can contain very different flavonoid profiles.

For FruitFast, anthocyanins are particularly relevant because they occur in several of the deeply colored fruits we work with, including tart cherries, wild blueberries, aronia berries, cranberries, raspberries, black currants, and grapes.

Explore Flavonoids →
Explore Anthocyanins →

Phenolic Acids

Phenolic acids are another broad group of naturally occurring phenolic compounds found in plant foods.

Examples include caffeic acid, ferulic acid, and p-coumaric acid, along with related compounds and derivatives.

As with other polyphenols, the specific phenolic-acid profile of a food depends on the plant, variety, growing conditions, processing, and analytical methods used to measure it.

Explore Phenolic Acids →

Stilbenes

Stilbenes represent a much smaller group of dietary polyphenols than flavonoids.

One of the best-known examples is resveratrol, a compound commonly associated with grapes and grape-derived foods.

Resveratrol has attracted substantial scientific interest, but research involving isolated resveratrol should not automatically be interpreted as evidence about grapes, grape juice, or other polyphenol-containing foods as a whole.

Explore Resveratrol →

Lignans

Lignans are phenolic compounds found in a variety of plant foods, particularly certain seeds and grains, although they also occur in other foods.

They are usually discussed separately from flavonoids, phenolic acids, and stilbenes when researchers describe major dietary polyphenol groups.

Compared with some other polyphenol groups discussed in this guide, lignans are more commonly associated with foods such as seeds and grains than with the deeply colored fruits highlighted throughout FruitFast's fruit research resources.

Which Fruits Contain Polyphenols?

Polyphenols occur in a wide variety of fruits, but different fruits contain different mixtures of individual compounds.

The color of a fruit can sometimes provide clues about certain polyphenols it contains. For example, anthocyanins contribute to many red, purple, and blue fruit colors. However, color alone does not provide a complete measurement of a fruit's polyphenol composition.

Researchers use analytical methods to identify and measure individual compounds in fruit. The reported amounts can vary with cultivar, growing conditions, ripeness, storage, processing, and the laboratory methods used.

For that reason, it is more useful to ask which polyphenols have been identified in a particular fruit than simply whether a fruit is “high in polyphenols.”

Tart Cherries

Tart cherries contain multiple classes of phenolic compounds rather than one single “active” compound.

Research examining tart cherry composition has identified anthocyanins, other flavonoids, and phenolic acids. Anthocyanins are particularly recognizable because they contribute to the red coloration of tart cherries.

The particular compounds and amounts reported can vary among cherry cultivars, growing conditions, processing methods, and analytical techniques.

This chemical diversity is one reason research involving whole tart cherry juice or concentrate should not automatically be interpreted as research involving anthocyanins alone.

Explore Tart Cherries →
Explore Anthocyanins →
Explore Tart Cherry Research →

Wild Blueberries

Wild blueberries contain a diverse mixture of polyphenols, with anthocyanins among their most recognizable groups.

Their dark blue and purple pigmentation reflects the presence of multiple anthocyanin compounds rather than a single pigment.

Blueberries also contain other flavonoids and phenolic compounds. As with tart cherries, their composition can vary with factors such as genetics, maturity, growing conditions, storage, and processing.

Explore Wild Blueberries →
Explore Anthocyanins →

Aronia Berries

Aronia berries—sometimes called chokeberries—are deeply pigmented fruits containing several types of polyphenols.

Researchers have identified anthocyanins, proanthocyanidins, flavonols, and phenolic acids among the phenolic compounds occurring in aronia.

Aronia is a useful example of why the term “polyphenols” should not be reduced to anthocyanins alone: deeply colored fruits can contain several different phenolic families simultaneously.

Explore Aronia →

Cranberries

Cranberries contain a varied mixture of phenolic compounds that includes anthocyanins, flavonols, phenolic acids, and proanthocyanidins.

Different cranberry products can have substantially different compositions depending on the fruit material used and how the product is processed.

This is another reason findings involving an isolated cranberry compound should not automatically be treated as evidence for every cranberry food, juice, or concentrate.

Explore Cranberries →

Grapes

Grapes contain several families of polyphenols, and their profiles vary considerably by grape variety and by different parts of the fruit.

Depending on the grape, researchers may identify compounds belonging to groups such as anthocyanins, flavan-3-ols, flavonols, phenolic acids, and stilbenes.

Resveratrol is one of the best-known grape-associated polyphenols, but it represents only one compound within a much more complex mixture.

Explore Grapes →
Explore Resveratrol →

Pomegranates

Pomegranates contain a complex mixture of phenolic compounds. Their composition differs among the juice, peel, seeds, and other parts of the fruit.

Among the compounds frequently discussed in pomegranate research are ellagitannins and related phenolic compounds, along with anthocyanins and other polyphenols.

Because different pomegranate preparations may contain different proportions of these compounds, research involving an extract or isolated constituent should not automatically be attributed to pomegranate juice or juice concentrate.

Explore Pomegranates →

Blackberries, Raspberries & Black Currants

Other deeply colored berries also provide diverse examples of fruit polyphenols.

Blackberries and raspberries contain anthocyanins along with ellagitannins and other phenolic compounds, while black currants are particularly recognized for their anthocyanin content.

As with the other fruits discussed here, the exact profile depends on the fruit variety, maturity, processing, and method of analysis.

These differences illustrate an important theme throughout this guide: polyphenol-rich fruits are chemically complex foods, not interchangeable sources of a single compound.

Are Polyphenols Antioxidants?

Polyphenols are frequently described as antioxidants, but the relationship between polyphenols and antioxidant activity is more complicated than the term can make it sound.

In laboratory experiments, many polyphenols can participate in chemical reactions involving oxidation and reactive molecules. Foods containing polyphenols can also demonstrate antioxidant activity in laboratory tests.

However, a laboratory measurement of antioxidant capacity does not automatically tell us what will happen after a person eats that food.

After consumption, polyphenols may be absorbed, metabolized, transformed by the gut microbiota, converted into metabolites, and eliminated from the body. Different compounds can have very different bioavailability and metabolism.

For this reason, modern polyphenol research extends beyond the simple idea that dietary polyphenols enter the bloodstream and directly “neutralize free radicals.”

Researchers instead investigate a much broader range of questions, including how polyphenols and their metabolites are absorbed and metabolized, how they interact with biological pathways, and whether consuming particular foods or compounds is associated with measurable changes in humans.

The ability of a food to demonstrate antioxidant activity in a laboratory test should therefore not be interpreted as proof of a particular health effect in people.

What About ORAC Scores?

ORAC, or Oxygen Radical Absorbance Capacity, is a laboratory method that has been used to measure antioxidant capacity.

ORAC values became widely used in marketing to compare foods and ingredients. However, an ORAC measurement is an in vitro laboratory result and does not establish how a food will affect antioxidant processes or health outcomes in the human body.

The USDA previously published a database of ORAC values for selected foods. The database is no longer maintained as a current USDA food-composition resource. More broadly, ORAC values represent laboratory measurements and should not be interpreted as direct evidence of antioxidant effects or health outcomes in the human body.

For that reason, FruitFast does not use ORAC scores as a ranking system for determining which fruit is “healthiest” or as proof that one fruit will produce a particular effect in people.

What Happens to Polyphenols After You Eat Them?

Eating a polyphenol-containing food is only the beginning of what researchers call bioavailability and metabolism.

Polyphenols differ considerably in their chemical structures, which affects how they behave during digestion and after absorption.

Depending on the compound, only a portion may be absorbed in its original form. Many undergo transformations in the digestive tract, intestinal tissues, liver, or other tissues. Gut microorganisms can also transform some polyphenols into smaller metabolites.

As a result, the compounds circulating in the body after eating a polyphenol-containing food may not be identical to the compounds originally present in that food.

Researchers therefore study not only which polyphenols a food contains, but also:

• how much is consumed;
• how compounds are released from the food;
• how they are absorbed;
• how they are metabolized;
• which metabolites are produced;
• how long those compounds or metabolites remain detectable; and
• whether measurable biological outcomes change.

This helps explain why the phrase “contains polyphenols” is not, by itself, evidence of a particular effect in humans.

Bioavailability Is Not the Same for Every Polyphenol

Different polyphenols can have substantially different patterns of absorption and metabolism.

Even compounds within the same broad family may behave differently. Food composition, dose, preparation, individual metabolism, and interactions with the gut microbiota can also influence what happens after consumption.

This complexity is one reason researchers increasingly examine polyphenol metabolites rather than focusing only on the original compounds found in a food.

It is also why findings involving a purified compound cannot automatically be applied to a whole fruit—and findings involving a whole fruit cannot automatically be attributed to one individual polyphenol.

What Does Human Polyphenol Research Study?

Human polyphenol research asks many different questions, and not every type of study provides the same kind of evidence.

Some studies investigate what happens to polyphenols after they are consumed. Others examine whether eating a particular food, drinking a beverage, or consuming a specific compound is associated with measurable differences in biological markers or other outcomes.

Researchers have studied polyphenols and polyphenol-rich foods in relation to areas such as metabolism, vascular function, exercise, cognition, gut microbiota, and markers related to oxidative and inflammatory processes.

However, the fact that a topic has been studied does not mean that a particular benefit has been established. Results must be interpreted in the context of the study design, participants, food or compound tested, dose, duration, outcomes measured, and the overall body of evidence.

Observational Studies vs. Intervention Trials

Observational studies examine patterns that already exist among groups of people. Researchers might compare dietary intake with health measurements or follow participants over time to look for associations.

These studies can identify potentially important relationships, but an association does not by itself prove that polyphenols—or a particular food containing them—caused the observed difference.

Intervention trials deliberately assign participants to consume a food, beverage, extract, supplement, or isolated compound and compare outcomes with another intervention or control.

Randomized controlled trials can provide stronger evidence about cause and effect, but their conclusions still depend on factors such as study size, duration, participant characteristics, the intervention tested, adherence, and the outcomes measured.

For this reason, FruitFast looks at the overall body of evidence rather than treating one study as definitive proof.

Biomarkers Are Not the Same as Health Outcomes

Many nutrition studies measure biomarkers—laboratory or physiological measurements that researchers use to investigate changes occurring in the body.

Depending on the research question, these might include measurements from blood or urine, concentrations of polyphenol metabolites, markers related to oxidative processes, inflammatory markers, blood pressure, or other physiological measurements.

Biomarkers can provide useful scientific information, but a statistically significant change in a biomarker does not automatically establish a meaningful long-term health outcome.

The significance of a finding depends on what was measured, the size and consistency of the effect, the quality of the study, and whether similar findings have been reproduced in other research.

Whole Foods vs. Extracts vs. Isolated Compounds

Human polyphenol studies do not all test the same type of intervention.

Researchers may study:

• whole fruits;
• fruit juices or beverages;
• juice concentrates;
• powders;
• extracts;
• supplements; or
• purified individual compounds.

A purified anthocyanin, for example, is not chemically equivalent to a whole berry containing anthocyanins alongside sugars, acids, fiber, vitamins, minerals, and numerous other plant compounds.

Likewise, an extract standardized for one group of polyphenols should not automatically be considered equivalent to a juice or juice concentrate.

The exact material used in a study matters when interpreting what that study actually tells us.

Why Individual Responses Can Differ

Even when people consume the same polyphenol-containing food or compound, their biological exposure may not be identical.

Human research has found considerable inter-individual variability in polyphenol metabolism and bioavailability. Factors being investigated include differences in gut microbiota, genetics, age, diet, physiology, and other individual characteristics.

This means that researchers increasingly consider not only the average response of a study group, but also why different people may metabolize the same compounds differently.

These differences are another reason to be cautious about translating a population-level research finding into a guaranteed individual response.

How FruitFast Evaluates Polyphenol Research

When reviewing research for FruitFast Health Information resources, we consider more than whether a study reports a statistically significant result.

We look at factors including:

• Study design — Was the research observational, controlled, randomized, blinded, or a systematic review?
• Participants — Who was studied, and how many people participated?
• Material tested — Was the intervention a whole fruit, juice, concentrate, extract, supplement, or isolated compound?
• Amount and duration — How much was consumed and for how long?
• Outcomes measured — Did researchers measure biomarkers, symptoms, physical performance, dietary patterns, or other outcomes?
• Comparison group — What was the intervention compared with?
• Consistency — Have similar findings appeared in other studies?
• Limitations — What factors restrict how broadly the findings can be interpreted?
• Funding and conflicts of interest — Were relevant financial or commercial relationships disclosed?

This approach helps distinguish between what a study actually found and broader claims that the research may not support.

Polyphenols in Whole Fruit, Juice & Juice Concentrate

Polyphenols can be present in whole fruits as well as foods and beverages made from fruit, but these forms are not nutritionally or chemically identical.

Whole fruit contains the edible structures of the fruit, including components such as water, carbohydrates, fiber, organic acids, vitamins, minerals, and numerous plant compounds.

Fruit juice is produced by separating juice from much of the solid fruit material. Depending on the fruit and processing method, the resulting juice can retain many naturally occurring compounds from the fruit while containing substantially less fiber than the whole fruit.

Juice concentrate is produced by removing a portion of the water from juice. This reduces its volume and increases the concentration of soluble components, but the exact composition of a concentrate depends on the fruit, starting juice, processing conditions, and degree of concentration.

Because processing can affect individual compounds differently, it should not be assumed that every polyphenol present in fresh fruit will be present in exactly the same amount or proportion in every juice, concentrate, powder, or extract.

Does Concentrating Juice “Create” More Polyphenols?

Concentrating fruit juice does not create new polyphenols simply because water has been removed.

Instead, removing water can increase the amount of existing soluble components per unit of volume or weight, depending on how the concentration is measured and how the product is processed.

This distinction is important when comparing a single-strength juice with a concentrated juice. A comparison must account for factors such as serving size, concentration level, analytical method, and whether results are reported per gram, per milliliter, per serving, or relative to the original fruit.

For this reason, statements about one product containing “more polyphenols” require appropriate analytical data and a clearly defined basis for comparison.

Does Processing Destroy Polyphenols?

Processing can change the polyphenol composition of fruit products, but the effect is not accurately described by a simple rule that processing either “preserves” or “destroys” all polyphenols.

Individual compounds differ in their stability. Changes can depend on factors such as temperature, oxygen exposure, light, pH, processing time, storage conditions, and the particular fruit and compound being studied.

Some compounds may decrease during processing or storage, while others may remain relatively stable or become more extractable or measurable as the food matrix changes.

The best way to determine the composition of a particular fruit product is therefore through appropriate analysis of that product rather than assumptions based solely on the processing method.

Frequently Asked Questions

Continue Exploring Fruit Polyphenols

Polyphenols include many different families and individual compounds. Explore the FruitFast Health Information library to learn more about specific compounds, fruits, and areas of research.

Anthocyanins
Learn about the pigments responsible for many red, purple, and blue fruit colors and how anthocyanins fit within the larger flavonoid family.
Explore Anthocyanins →

Flavonoids
Explore the larger polyphenol family that includes anthocyanins, flavonols, flavanones, flavones, and flavan-3-ols.
Explore Flavonoids →

Phenolic Acids
Learn about caffeic acid, ferulic acid, p-coumaric acid, and other phenolic acids occurring in plant foods.
Explore Phenolic Acids →

Antioxidants, Free Radicals & Oxidative Stress
Learn why laboratory antioxidant activity and antioxidant processes in the human body are not the same thing.
Explore Antioxidants & Oxidative Stress →

Exercise, Muscle Recovery & Tart Cherries
Explore human research examining tart cherry products in exercise and recovery settings.
Explore the Research →

Health Information & Fruit Nutrition Research
Browse FruitFast's complete library of fruit, nutrition, plant-compound, and research resources.
Explore Health Information →

FruitFast Fruit Juice Concentrates

FruitFast produces juice concentrates from many of the fruits discussed in this guide, including tart cherries, wild blueberries, aronia berries, cranberries, grapes, pomegranates, and other fruits.

Product composition, ingredients, serving information, and preparation instructions can be found on the individual product pages.

Research and educational information discussed on this page should not be assumed to apply equally to every FruitFast product.

Explore FruitFast Juice Concentrates →

Scientific References & Sources

The following scientific publications and authoritative resources were used in preparing this guide. References are provided so readers can examine the underlying research and scientific context.

1. Manach C, Scalbert A, Morand C, Rémésy C, Jiménez L. Polyphenols: food sources and bioavailability. American Journal of Clinical Nutrition. 2004;79(5):727–747. doi:10.1093/ajcn/79.5.727. PMID: 15113710.

2. Manach C, Williamson G, Morand C, Scalbert A, Rémésy C. Bioavailability and bioefficacy of polyphenols in humans. I. Review of 97 bioavailability studies. American Journal of Clinical Nutrition. 2005;81(1 Suppl):230S–242S. doi:10.1093/ajcn/81.1.230S. PMID: 15640486.

3. Williamson G, Manach C. Bioavailability and bioefficacy of polyphenols in humans. II. Review of 93 intervention studies. American Journal of Clinical Nutrition. 2005;81(1 Suppl):243S–255S. doi:10.1093/ajcn/81.1.243S. PMID: 15640487.

4. Kay CD, Clifford MN, Mena P, et al. Recommendations for standardizing nomenclature for dietary (poly)phenol catabolites. American Journal of Clinical Nutrition. 2020;112(4):1051–1068. doi:10.1093/ajcn/nqaa204. PMID: 32936878.

5. Williamson G. Bioavailability of Food Polyphenols: Current State of Knowledge. Annual Review of Food Science and Technology. 2025;16(1):315–332. doi:10.1146/annurev-food-060721-023817. PMID: 39899845.

6. Yan Y, Li X, Zhang C, et al. Phenolic profiles and their responses to pre- and post-harvest factors in small fruits: a review. Critical Reviews in Food Science and Nutrition. 2023;63(19):3574–3601. doi:10.1080/10408398.2021.1990849.

7. Pappas E, Schaich KM. Phytochemicals of cranberries and cranberry products: characterization, potential health effects, and processing stability. Critical Reviews in Food Science and Nutrition. 2009;49(9):741–781. doi:10.1080/10408390802145377. PMID: 20443158.

8. Pirzadeh M, Caporaso N, Rauf A, et al. Pomegranate as a source of bioactive constituents: a review on their characterization, properties and applications. Critical Reviews in Food Science and Nutrition. 2021;61(6):982–999. doi:10.1080/10408398.2020.1749825. PMID: 32314615.

9. Jurikova T, Mlcek J, Skrovankova S, et al. Aronia melanocarpa Products and By-Products for Health and Nutrition: A Review. Antioxidants. 2021;10(7):1052. doi:10.3390/antiox10071052. PMID: 34209985.

10. Sabou VR, O'Leary MF, Liu Y, Brown PN, Murch S, Bowtell JL. Review of Analytical Methods and Reporting of the Polyphenol Content of Tart Cherry Supplements in Human Supplementation Studies Investigating Health and Exercise Performance Effects: Recommendations for Good Practice. Frontiers in Nutrition. 2021;8:652094. doi:10.3389/fnut.2021.652094. PMID: 33842524.

11. U.S. Department of Agriculture, Agricultural Research Service. USDA Database for the Oxygen Radical Absorbance Capacity (ORAC) of Selected Foods. Nutrient Data Laboratory; 2007.

Educational Information

Educational Information: This page is provided for general educational purposes and is intended to summarize scientific concepts and research related to polyphenols and fruit. It is not intended to diagnose, treat, cure, or prevent any disease and should not be considered medical advice. Research findings discussed on this page should not be assumed to apply to every fruit, food, juice, concentrate, extract, supplement, or individual.