Polyphenols are a family of organic molecules widely distributed throughout the plant world and in many foods.
Among other things, they are responsible for the flavour and colour of plants.
Examples include flavonoids, responsible for the bitterness of grapefruit, tannins, responsible for the astringency of various fruits, and anthocyanins, responsible for the colour of red fruits.
Their role in plants is essential, but they are also important for humans.
They are best known for their antioxidant properties, helping to combat the formation of free radicals, which in excess can have serious consequences in the body.
Free radicals are substances that promote cellular ageing and the early onset of certain diseases.
The importance of diet in maintaining good health is well established.
Studies are providing more and more information about the relationship between the foods we eat and our health, and their relationship with the development or prevention of certain diseases.
The benefits
There are many families of polyphenols and these are known to be powerful antioxidants that reduce the damage caused by free radicals in the body.
This antioxidant role mainly allows to prevent the oxidation of cells and therefore to fight against premature cellular ageing, which includes all the phenomena that allow an organism to evolve by modifying its structure and functions.
For this role, polyphenols have many virtues and benefits for our entire body.
Free radicals are favoured every day by external factors such as pollution or excessive exposure to UV rays.
This exposure increases the visible signs of skin ageing.
By scavenging free radicals, polyphenols help combat the harmful effects of UV rays.
By greatly reducing the degradation of collagen and elastin by free radicals, polyphenols also limit the appearance of wrinkles.
Cosmetic laboratories are also interested in these molecular compounds in order to incorporate them into specific "anti-aging" creams.
A preventive role in certain diseases
Polyphenols can reduce risk factors for cardiovascular disease.
In fact, they promote good glycaemic balance, fight cholesterol oxidation, reduce atherosclerosis and act against insulin resistance and hypertension.
They are also an ally against certain types of cancer, preventing the formation of tumours and limiting the formation of molecules at the origin of genetic mutations harmful to the body.
Polyphenols are also recommended as part of an "anti-cancer" diet.
In general, polyphenols have a preventive effect in various diseases involving cellular deterioration, whether metabolic, inflammatory or neurodegenerative.
Each polyphenol has a more specific role.
For example, resveratrol plays a key role in maintaining a good cardiovascular system, catechins in maintaining good blood sugar levels, and curcumin in reducing inflammation and mitochondrial dysfunction.
Food sources
To date, more than 500 polyphenols have been identified.
Polyphenols are divided into several categories, the best known being flavonoids and tannins.
They are generally found in all fruits and vegetables:
- Grapes
- Persimmons
- Cherries
- Blackberries
- Blueberries
- Raspberries
- Strawberries and other red fruits
- Apples
- Grapefruit
- Potatoes
- Aubergines
- Broccoli
- Red onion
- ...
But they are also present in greater or lesser quantities in the following:
- Cocoa and therefore in dark chocolate
- Peanut
- Linseed
- Saffron
- Ginger
- Soya
- Red wine
- Green, black or white tea
There are no daily recommendations for polyphenols.
However, they should not be consumed in excess, as excessive consumption can reduce the body's absorption of iron.
It is therefore advisable to simply eat a good, balanced and complete diet, including fruit and vegetables every day, without neglecting the other food families.
Chemical property
Polyphenols are often divided into several families and include
- Flavones
- Flavonols
- Anthocyanidins
- Isoflavones
- Flavonones
- Catechins
- Resveratrol
- Phenolic acids
- Lignans
These are characterised, as the name suggests, by the presence of at least two associated phenols in more or less complex structures, generally of high molecular weight.
They are molecules containing at least one benzene ring and hydroxyl groups.