Coffee, chocolate, tea, red wine, olive oil, vegetables, fruits, herbs, and spices are among the richest foods in polyphenols. They can help us get 1,000 mg of polyphenols a day, which is a considered a relatively high dosage. We can get more than enough polyphenols by following a whole-food, plant-based diet. Only plants are good dietary sources.
What are polyphenols?
Polyphenols are plant compounds that have powerful antioxidant properties. These phytochemicals give food its color, flavor, or bitterness. Polyphenols protect plants from oxidation. Additionally, they protect the human body from free radical damage and UV radiation. There are over 8,000 polyphenols.
Several epidemiological studies strongly showed that the consumption of polyphenols have beneficial effects on chronic diseases such as cancer, cardiovascular disease, diabetes, neurodegenerative diseases, and aging.
Recommended Daily Intake of Polyphenols
Polyphenols don’t have an officially approved recommended daily intake value, like vitamins and minerals. Polyphenols don’t store in the body. So, their health effects are difficult to be measured. Also, it’s difficult to measure their bioavailability.
Many studies have been conducted to find the daily polyphenol consumption of the population around the globe. For instance, scientists measured that the daily intake of polyphenols was between 183–4,854 mg per day in Japan (5).
On the contrary, in the famous EPIC study, scientists measured that the daily intake of polyphenols was 584–1,786 mg per day (6).
The EPIC study is a well-known large study conducted in 10 European countries: Denmark, France, Germany, Greece, Italy, Norway, Spain, Sweden, The Netherlands, and the UK. Scientists tried to investigate the role of diet, and other environmental factors on the etiology of cancer, and other chronic diseases. Over half a million participants were recruited. The highest total polyphenol intake was in Denmark (1,786 mg per day), whereas the lowest polyphenol intake was in Greece (584 mg per day).
Actually, the daily polyphenol intake is on average 1,000 mg. It depends on lifestyle and dietary preferences (11).
According to certain studies, we should get at least 500 mg of polyphenols a day for greater health benefits (9).
Most noteworthy, high consumption of polyphenols is unlikely to cause toxicity or side effects (7).
Therefore, you should increase the daily consumption of foods rich in polyphenols. The easiest way to really boost the polyphenol intake is by following a whole-food plant-based diet. Vegetables, fruits, beans, legumes, herbs, and spices are particularly rich in polyphenols!
Types of Polyphenols
Polyphenols are divided into four different categories (1):
- Flavonoids are predominantly in fruits, vegetables, legumes, red wine, and green tea. They are further divided into flavones, flavonols, flavanones, isoflavones, anthocyanidins, chalcones, and catechins. They have potential health benefits as complementary medicine and utilized in various formulation implied for antioxidant, anti-inflammatory, neuroprotective, anti-diabetic, anticancer, anti-infertility, anti-obesity, anti-arthritic, neuroprotective, antihyperlipidemic, anti-cataract and wound healing properties (1).
- Stilbenes are found in red wine, grapes, and peanuts. The most well-known compound of this group is resveratrol.
- Phenolic acids are found in coffee, tea, cinnamon, blueberries, kiwis, plums, apples, and cherries.
- Lignans are found in seeds. Flaxseed is particularly rich in lignans. Legumes, whole-cereals, whole-grains, fruits, algae, and certain vegetables are good dietary sources as well.
Food usually contains complex polyphenols, mainly found in the outer layers of the plants. Thus, avoid peeling fruits and vegetables. Prefer organic foods, as herbicides and pesticides tend to accumulate in the skin.
Health benefits of Polyphenols
Polyphenols protect plants from UV radiation, pathogens, oxidative stress, and harsh climatic conditions.
Polyphenols are so important for the human body as well. They can prevent several major chronic diseases associated with oxidative stress. Actually, polyphenols have many powerful biological properties such as (1,2,8,9):
- cerebrovascular protection
- antibacterial and
- antiviral properties
The richest food in polyphenols
Plants are the only good dietary sources of polyphenols. Fruits, vegetables, legumes, whole-cereals, dark chocolate, tea, and coffee are all rich in polyphenols.
The richest food in polyphenols is cloves. They contain 15,000 mg of polyphenols per 100g (2).
Actually, all spices and herbs are particularly rich in polyphenols. For instance, oregano, sage, rosemary, spearmint, and thyme can significantly increase the polyphenol content of a meal.
List of common foods rich in polyphenols
As, we can’t consume large amounts of spices and herbs, we should consume a wide variety of vegetables and fruits. According to the American Heart Association, we have to consume at least 5 servings of fruits and vegetables a day.
Fruits high in polyphenols
Most common fruits, such as grapes, cherries, plums, apples, peaches, apricots, nectarines, pears, and berries, contain up to 300 mg of polyphenols per 100g.
Berries are particularly rich is anthocyanins. Black chokeberry, black elderberry, blueberry, strawberries, and blackcurrant are all rich in polyphenols. Due to their unique nutritional value, berries are great for weight loss. Hence, you can enjoy raspberries, blueberries, and other berries, as part of a low-calorie diet for weight loss.
Some fruit juices also contain great amounts of polyphenols. For instance, pomegranate juice is particularly rich in polyphenols and other antioxidants.
Vegetables, seeds, nuts & beans are good dietary sources of polyphenols
Chestnuts, walnuts, hazelnuts, pecans, almonds, and flaxseeds are nuts and seeds rich in polyphenols.
Cocoa powder and chocolate are also rich in polyphenols.
Soy flour and roasted soybean are rich in isoflavones.
Black and green olives are particularly rich in tyrosols. Other vegetables that contain polyphenols are globe artichoke heads, green chicory, red and yellow onions, shallots, spinach, broccoli, asparagus, potatoes, endive, lettuce, endive, and carrot.
Furthermore, cereals, such as wheat or rye, contain some polyphenols.
Last, but not least, only two vegetable oils contain polyphenols: the extra virgin olive oil and the rapeseed oil.
Polyphenols in green tea, coffee, wine & beer
In addition, coffee, black tea, green tea, and red wine are beverages rich in polyphenols. Typically, a cup of tea or coffee or a glass of red wine contains more than 100 mg of polyphenols. In fact, coffee and green tea can be the main sources of polyphenols for people who follow the standard Western diet (5).
Also, red wine is rich in polyphenols. In fact, red wine has 10 times more polyphenols than white wine. Rosé wine has a low polyphenol content as well. It has only 7.8 mg of polyphenols per 100 mL. Each wine variety has a slightly different polyphenol content, though.
Beer, red wine, and coffee substantially contribute to the total polyphenol intake, although they have a low to moderate polyphenol content. That’s because most people consume high amounts of these beverages.
The consumption of cocoa, tea or coffee could increase the daily polyphenol intake by 500–1,000 mg (7).
- NCBI – PMC: A Critical Review on Polyphenols and Health Benefits of Black Soybeans
- Nature.com – European Journal of Clinical Nutrition: Identification of the 100 richest dietary sources of polyphenols: an application of the Phenol-Explorer database
- Office of Disease Prevention and Health Promotion (ODPHP): Dietary Guidance for Americans 2015-2020
- NCBI – PMC: The role of polyphenols in modern nutrition
- NCBI – PMC: Estimated Dietary Polyphenol Intake and Major Food and Beverage Sources among Elderly Japanese
- NCBI – PMC: Dietary polyphenol intake in Europe: the European Prospective Investigation into Cancer and Nutrition (EPIC) study
- British Journal of Nutrition: Dietary reference intake (DRI) value for dietary polyphenols: are we heading in the right direction?
- NCBI – PMC: Effects of Polyphenol-Rich Foods on Human Health
- NCBI – PMC: Systematic Review on Polyphenol Intake and Health Outcomes: Is there Sufficient Evidence to Define a Health-Promoting Polyphenol-Rich Dietary Pattern?
- Oxford Academic – The Journal of Nutrition: Dietary Intake and Bioavailability of Polyphenols
- NCBI– PMC: Tea polyphenols, their biological effects and potential molecular targets