How Do Polyphenols Work?

Medically Reviewed on 12/16/2020
A polyphenol-rich diet helps keep the heart, nerves, and blood vessels healthy.
A polyphenol-rich diet helps keep the heart, nerves, and blood vessels healthy.

Polyphenols are naturally occurring chemical compounds found in many plant-based foods and are good for our bodies. They are powerful antioxidants, meaning they fight potentially damaging chemicals formed inside our cells as a result of stress and aging.

A polyphenol-rich diet helps keep the heart, nerves, and blood vessels healthy. It maintains skin texture and elasticity and eye health. Polyphenols can protect your organs from infections and even some cancers.

These super nutrients are found in various fruits and vegetables. Colorful vegetables such as eggplants, apples, plums, bell peppers, purple grapes, violet carrots, green tea, and tomatoes are rich in polyphenols. Unlike vitamins, they are not sensitive to oxidation (loss of oxygen) or light and even after cooking are kept well inside the food.

To date, over 8,000 polyphenols have been identified in edible plants and largely classified into four categories based on their chemical structure: flavonoids, phenolic acids, lignans, and stilbenes. Flavonoids and phenolic acids make up most of your polyphenols in your diet, whereas stilbenes and lignans are less common (except, resveratrol in red wine). They also differ as per the site of absorption in the human body. Some of the polyphenols are well absorbed in guts.

We need various polyphenols to keep your gut, brain, and heart strong and healthy. They play a role in

  • Brain function improvement: They improve brain functions by boosting brain cell structure and slowing down brain aging and memory.
  • Maintaining good gut bacteria: Polyphenol in blueberries may help to grow the number of good bacteria in your gut and improve digestion.
  • Maintaining a healthy heart: Flavonoid-rich foods may improve heart health by reducing blood clot formation and inflammation, as well as by lowering blood pressure. Polyphenols such as flavonoids and resveratrol may block and reduce bad cholesterol and lower the risk of cardiovascular disease.
  • Blood sugar control: Dietary flavonoids and phenolic acids may help to reduce blood sugar spikes and type 2 diabetes risks. Several polyphenols may prevent and manage diabetes by protecting beta cells of the pancreas from glucose toxicity, reducing inflammation, and slowing down starch digestion.
  • Weight management: Various polyphenols including those in green tea may make it easier to maintain or lose weight, potentially through fat cell reduction, inhibition of fat cell production, reduction of inflammation, and increasing energy expenditure. Some polyphenols may have protein-binding properties, which inhibit starch and encourage fat and protein digestion.
  • Inflammation reduction: Certain dietary polyphenols may neutralize the effect of free radicals, which are the unstable molecules that cause aging and stress in your body cells. It is also associated with lowering inflammation by mitigation of cytokines (proteins that regulate inflammation) and reduce pain.
  • Protection against cancer: Flavonoids may neutralize free-radicals and reduce cancer risk by arresting tumor growth. It may protect against certain cancers in the colon, prostate, womb, and breast.

What are the sources of polyphenols?

Polyphenols found in various plant-based food items such as:

  • Apples
  • Red wine
  • Dark chocolate
  • Olive oil
  • Herbs and spices such as cinnamon, oregano, and turmeric
  • Whole grains
  • Tea (green or black)
  • Coffee
  • Red onions
  • Grapes
  • Soybeans
  • Legumes
  • Cereals and grains
  • Capers
  • Saffron
  • Flaxseeds
  • Mangoes
  • Vegetables such as spinach, cabbage, and asparagus
  • Citrus fruits
  • Avocado
  • Olives
  • Berries (blackcurrant, blueberries, cherries strawberries, and raspberries)

What are the benefits of polyphenols?

Epidemiological studies have strongly suggested that long-term consumption of diets rich in polyphenols offer protection against several chronic diseases such as:

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Medically Reviewed on 12/16/2020
References
Shiel WC Jr. Medical Definition of Polyphenol. Medicinenet. https://www.medicinenet.com/polyphenol/definition.htm

Pandey KB, Rizvi SI. Plant Polyphenols as Dietary Antioxidants in Human Health and Disease. Oxid Med Cell Longev. 2009;2(5):270-278. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2835915/

Fraga CG, Croft KD, Kennedy DO, et al. The Effects of Polyphenols and Other Bioactives on Human Health. Food Funct. February 20, 2019;10(2):514-528. https://pubs.rsc.org/en/content/articlelanding/2019/fo/c8fo01997e#!divAbstract