Polyphenols are natural compounds found in many plant-based foods and are great for your health.
Polyphenols are micronutrients present in many plant-based foods and beverages. They have antioxidant properties, so they may play a role in preventing many common diseases associated with oxidative stress.
Oxidative stress occurs in the body when large numbers of free radicals overwhelm the body’s natural repair systems. Free radicals are oxygen-containing molecules that have an uneven number of electrons.
This makes them unstable, so they hunt for an electron to pair with their odd one. That’s why free radicals easily react with other molecules, leading to oxidation. Oxidative damage is a major cause of many chronic illnesses.
Antioxidants work by donating an electron to the free radical. This donation makes the free radical less reactive, but the antioxidant itself remains stable. When this system isn’t working properly, your body is more prone to certain illnesses.
Polyphenols are the most abundant antioxidant in the human body, and they come from plant foods. Hundreds of polyphenols have been identified in foods. There are two main types: flavonoids and phenolic acids, of which your recommended dietary intake is approximately one gramme per day.
Different types of polyphenol and their food sources –
Polyphenols are responsible for some of the bright and vibrant colours of fruits and vegetables. Eating polyphenol rich foods is like eating (and tasting) the rainbow.
Flavonoids
catechin, quercetin, hesperetin, cyanidin, daidzein, proanthocyanidins which are found in onions, tea, apples, citrus fruits, red fruits, soybeans, grapes, cocoa, red wine.
Phenolic acids
caffeic acid, ferulic acid Found in fruits, vegetables, whole grains, cereals, coffee.
Other polyphenols
resveratrol, ellagic acid, lignans Found in Grapes, red wine, strawberries, raspberries, flax, sesame seeds and grains.
How do polyphenols prevent disease?
Because of their antioxidant properties, polyphenols can limit oxidative damage associated with ageing and degenerative disease. That means the risk of developing diseases which are more common as you get older like cancers, cardiovascular disease, and diabetes type II, can be reduced by antioxidants like polyphenols.
Heart disease
Cardiovascular disease is the number one cause of death worldwide, according to the World Health Organisation. Yet, most incidences of cardiovascular disease can be prevented by changing certain behaviours such as poor diet, physical inactivity, smoking, and alcohol consumption.
Type II diabetes
Just like cardiovascular disease, type 2 diabetes mellitus is a significant health burden and one which is, again, preventable. There is significant evidence pointing towards polyphenols and their ability to help prevent the disease.
Certain polyphenols like resveratrol, quercetin, catechins, and anthocyanins have all been shown to reduce bad cholesterol levels in the blood. They also lower blood sugar levels, both of which are implicated in the development of type II diabetes.
Dietary flavonoids are particularly important in the fight against diabetes. That’s because they not only have anti-inflammatory effects, but they improve both glucose (sugar) and lipid (fat) metabolism.
Cancer
So, we know polyphenols have anti-inflammatory and antioxidant effects, which must mean they can help prevent cancer, too, right? Exactly. In fact, scientists have increased their attention on polyphenols since it was found they can alter cancer cell growth.
Up to 95% of the polyphenols you eat travel (undigested) to the colon where they are broken down into smaller metabolites. Gut bacteria like Lactobacillus, Bifidobacteria, and Escherichia coli have all been identified as catalysts in the metabolism of polyphenols.
Polyphenols are considered prebiotics because they feed the Bifidobacteriain your gut. Therefore, they increase the population of the bacteria, promoting the health of your gut. The antioxidant properties of some polyphenols also make them promising candidates for the treatment of inflammatory gut diseases.
Another bacterial species which has a special relationship with polyphenols is Akkermansia muciniphila. This beneficial microbe accounts for up to 4% of your intestinal bacteria and is associated with lean body mass and obesity prevention.
