Polyphenols are a class of antioxidants found in plants. They are chemical compounds that plants produce to protect themselves against parasites, bacteria, ultraviolet radiation and cell injury. And when we eat those plants, or parts of those plants, we reap the benefits too. In fact, many of the active substances found in medicinal plants are made up of polyphenols.
Recently, polyphenols were nicknamed “lifespan essentials” as they actively work in your body to fatally sidetrack the way a disease takes hold and makes you sick. Although polyphenols are a class of antioxidant, their actions go far beyond simply addressing the oxidative stress antioxidants are famous for preventing. It seems that polyphenols enhance our health in even more complex ways than a typical antioxidant. In fact, even after polyphenols are broken down in your body, their by-products, or metabolites, are themselves actively protective compounds. These complex health-promoting actions continue to be vigorously researched because it wasn’t until the mid-90’s that polyphenols came to the attention of nutritionists, at that point overtaking the research on the more typically recognized antioxidants; vitamins and minerals.
Today, it is believed that polyphenols reduce the risk factors for, and play a supportive role in, the prevention of degenerative diseases, particularly cardiovascular diseases. “…it is well established that some polyphenols, administered as supplements or with food, do improve health status…” and “Epidemiologic studies tend to confirm the protective effects of polyphenol consumption against cardiovascular diseases.”1 Overall, polyphenols help to protect many body systems from the risks or ravages of many types of chronic disease.
Boosting one’s intake of antioxidant polyphenols on a daily basis is easy to do, and can be a tasty, epicurean adventure. Choose richly hued fruits, vegetable and whole grains. Eat the majority of fruits, grains and vegetables in an unrefined state, although a bit of mild cooking can sometimes increase the bioavailability of polyphenols in foods. Choose fruit juices that are dark in color with no added sugar such as blueberry, red grape and pomegranate. Teas are a very rich source of polyphenols. Caffeinated teas and coffees may be better sources as the decaffeinating process may remove polyphenols along with the caffeine. Making these food choices will afford you many times the amount of polyphenol-type antioxidants intake as compared to the amount of garden-variety antioxidants we might get; sometimes up to ten times higher. As polyphenol levels peak soon after consumption, you should graze on polyphenol-rich food choices throughout the day the keep your levels high.
Before we get any deeper into the explanation of polyphenols, let’s take a quick look at some of the terms you’ll come across in this article. The following definitions will give you a reference point should you need to look back to refresh your memory.
Antioxidant– a substance that inhibits oxidation; a substance that removes potentially damaging oxidizing agents in a living organism.
Polyphenols– a class of antioxidants found in plants; the most well-known of the polyphenols are the flavonoids.
Flavonoids– a grouping of several thousand compounds. More than 4,000 chemically unique flavonoids are known. Flavonoids are especially potent antioxidants and metal chelators. They are chemical compounds that plants produce to protect themselves from parasites, bacteria, ultraviolet radiation and cell injury. Certain flavonoids have much greater antioxidant activity than vitamins C and E or beta-carotene. In fact, flavonoids protect the antioxidant vitamins from oxidative damage. 2
The 6 subclasses of flavonoids – includes flavonols, flavones, isoflavones, flavanones, anthocyanidins and flavanols (catechins and proanthocyanidins).
Flavonoids, A Bonus For Chocolate Lovers
Writing in the prestigious BMJ (British Medical Journal), Dr. Oscar Franco and his team determined several factors including diet, exercise, body weight control and lifestyle changes could help reduce the risk of heart disease, a condition expected to claim the lives of nearly 24 million people worldwide by the year 2030. The study included an analysis of seven detailed research bodies that included more than 114,000 participants. All studies independently pointed to the conclusion that different levels of chocolate consumption were associated with a substantial reduction in the risk of cardio-metabolic disorders. Researchers found that the flavonoids passed to chocolate from the cocoa bean have a positive impact on health and were found to regulate insulin sensitivity and maintain blood pressure in the normal range. 3
Let’s start off by recognizing that it’s not a typo; there actually are two different compounds with very similar names; flavonols and flavanols. Sometimes you will even see the names are even used interchangeably, as if they were the same thing. Yet, these are two different substances, with chemically different structures, but names that are distressingly similar.
Like other flavonoids, flavanols and flavonols are pigments found in plants. Flavanols are the most abundant of the flavonoids. They are also called flavan-3-ols, because of an alcohol group on carbon 3 of one of the rings. They are also sometimes called catechins because catechins are the most abundant type of flavanol we have found. Other flavanols include epicatechin, epigallocatechin, theaflavin and proanthocyanadin. Good sources are teas, chocolate, berries, apples, grapes and red wine. Flavanols are not attached to sugar molecules.Flavonols, on the other hand, come linked to a sugar molecule. They absorb large amounts of UV light and are found in the skin and outer layers of plants. One of their functions is to act as a sunscreen for the plant. In turn, exposing fruits such as grapes and berries to more sunlight makes them produce more flavonols. Quercetin is the most common flavonol. Others are kaempferol, myricetin, rutin and azaleatin. Some high flavonol foods are blueberries, apples, apricots, yellow onions, broccoli, scallions, curly kale, cranberries, leeks, red wine and sweet cherries. 4
Oxidative Stress – a condition characterized by therelease of free radicals, resulting in an overabundanceand cellular degeneration; a biological system’sinability to detoxify or repair damage caused byexcessive free radicals in the system.
Carotenoids – a subclass of vitamin A; a furthersubclass are the carotenes, the most recognizablebeing beta-carotene.
The following diagram should help visually outline where everything fits into place.
Isoflavones are flavonoids with structural similarities to estrogens. This confers a pseudo-hormonal property on them which allows them to be categorized as phytoestrogens. Isoflavones are found almost exclusively in leguminous plants such as soya. Soya and its processed products are the main source of isoflavones in the human diet.
Polyphenols help regulate the activity of a wide range of enzymes and cell receptors. What does this mean? Well, let’s focus in on enzymes for a moment. Enzymes are proteins that act as catalysts for speeding up the rate of biological reactions without being used up themselves. Almost all chemical reactions in a cell need enzymes in order to occur at a rate sufficient to sustain life. Without enzymes, these reactions may occur but not at a rate fast enough to keep you alive.
What is a biological reaction you might ask? Digestion is a biological reaction, as is respiration, muscle contraction (remember, your heart is a muscle) and just about every other action in your body that keeps you alive. The names of many enzymes end in “ase”; lipase is an enzyme that breaks down fats.
When Plant Meets Pest
Fruits and vegetables, grown without pesticides in natural conditions, have innate mechanisms which allow them to fight off pests and disease, much like our own immune systems. When the plant becomes stressed by a pest or disease, these mechanisms kick in and help protect the plant. “Many polyphenols…are directly involved in the response of plants to different types of stress: they contribute to healing…of damaged areas [of the plant], they possess antimicrobial properties, and their concentrations may increase after infection…the polyphenol content of vegetables produced by organic or sustainable agriculture is certainly higher than that of vegetables grown without stress, such as those grown in conventional or hydroponic conditions. This was shown recently in strawberries, blackberries, and corn.”5 In a nutshell, left to their own devices, plants will produce more polyphenols if they have to fight off pests and disease on their own. If you must interfere, do it with natural methods.
FOOD SOURCES OF POLYPHENOLS
Thanks to a group of French scientists who compiled a polyphenol database containing 452 foods and 502 different types of polyphenols, we can now identify foods ranked best to least based on total amount of polyphenols per serving. This information was published in the Journal of the American College of Nutrition.
The top 25 richest food sources of polyphenols (per serving) include:
- Black Elderberry
- Black Chokeberry
- High bush blueberry
- Globe artichoke heads
- Coffee, filtered
- Low bush Blueberry
- Sweet Cherry
- Red Raspberry
- Flaxseed Meal
- Dark Chocolate
- Black Tea
- Green Tea
- Pure Apple Juice
- Whole Grain Rye Bread
- Red Wine
- Soy Yogurt
- Cocoa Powder
- Pure Pomegranate Juice
Honourable mentions also go to black olives, spinach, pecans, black beans, red onion, broccoli and soy milk. 6
1. American Journal of Clinical Nutrition
2. Prescription for Nutritional Healing, Fourth Edition, Phyllis A. Balch, CNC
4. Third Planet Food
5. American Journal of Clinical Nutrition
6. Dr. Mike.com
Carol Roy is a Natural Health Practitioner who received her diploma from the Alternative Medicine College of Canada in Montreal, Quebec. With 12 years experience in her area of expertise, natural health and wellness, Carol has also trained to become a fully qualified Reiki Master, Quantum Touch Practitioner, and Reflexologist.
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