For many years, polyphenols have been gaining increasing interest as natural compounds beneficial for health. This is confirmed by over 55,000 studies published in the last two decades. They are found in a variety of plant-based foods such as fruits, vegetables, whole grains, legumes, as well as in spices, tea, chocolate, and red wine.
Polyphenols constitute one of the most abundant groups of natural compounds in the plant kingdom, with currently more than 8,000 of them identified.
Polyphenols are characterised by their chemical structure containing multiple phenolic groups. They are grouped into four main categories as well as several subgroups, including flavonoids, phenolic acids, stilbenes, and lignans (see Table 1). Within plants, they primarily serve as defence mechanisms against environmental stressors, including ultraviolet radiation and pathogens. However, when we consume foods rich in polyphenols, these compounds can provide significant benefits to our own health.
Polyphenols: compounds with multiple benefits
One of the most studied and well-established effects of polyphenols is their powerful antioxidant activity. They work by neutralising oxidative stress, a factor capable of damaging our cells and the DNA they contain. This phenomenon is notably responsible for premature aging and the development of many chronic diseases, such as cardiovascular diseases, cancer, and neurodegenerative disorders. At the cellular level, polyphenols eliminate a wide range of free radicals (oxidative molecules) and indirectly inhibit the enzymes responsible for their production, while stimulating our antioxidant defences.
Polyphenols also possess anti-inflammatory properties by modulating molecular pathways involved in the inflammatory response. For example, they inhibit the activity of enzymes such as phospholipase A2 and COX, which play a role in the metabolism of arachidonic acid. The latter is a polyunsaturated fatty acid (from the omega-6 family) from which our body produces pro-inflammatory molecules called prostaglandins, through enzymes like phospholipase A2 and COX. This mechanism of action is similar to that of certain classes of drugs like NSAIDs (e.g., ibuprofen) and corticosteroids (e.g., cortisone), commonly prescribed for inflammation.
Polyphenols play a crucial role in maintaining health, as chronic inflammation is associated with many diseases, including heart diseases, type 2 diabetes, obesity, cancer, and autoimmune disorders.
Lastly, polyphenols have other beneficial properties for our health, including a positive modulation of our gut microbiota, influencing its composition and balance. Indeed, many polyphenols have probiotic and synbiotic properties.
Polyphenols: optimise your intake
To fully benefit from polyphenols’ advantages, it is generally recommended to aim for a daily intake of about 1 gram. Studies indicate that following a Mediterranean-style diet is an excellent option to achieve this goal.
However, it is essential to consider environmental factors such as soil type, exposure to light, precipitation, and methods of cultivation and storage. These elements have a significant influence on the polyphenol content of foods. To ensure an adequately rich consumption of polyphenols, it is recommended to prioritise sources from organic farming.
Furthermore, it is worth noting that the bioavailability of polyphenols varies considerably depending on the types of polyphenols. Thus, the total amount of polyphenols present in a food may not be entirely absorbed by the body.
Most polyphenols are liposoluble, meaning they are better absorbed in the presence of dietary fats. However, there are also hydrophilic polyphenols that are more easily absorbed when their food source is consumed with liquids.
Consequently, it is generally recommended to avoid consuming most polyphenols outside of main meals to not compromise their bioavailability and enhance their absorption.
In the context of preventing and managing chronic diseases, as well as slowing down aging due to oxidative stress and chronic inflammation, you can turn to supplements containing polyphenols. Opt for those that offer rich polyphenol blends as this can promote better bioavailability and optimal synergy of action.
In conclusion, polyphenols play a vital role in health, with benefits ranging from antioxidation to inflammation reduction, and their ability to modulate our gut microbiota. When integrated into a balanced diet like the Mediterranean diet, they combat chronic diseases and slow down aging. Understand their variable bioavailability and optimise their absorption through suitable dietary choices. When needed, well-chosen polyphenol supplements can be a judicious addition to enhance our overall well-being.
By Dr Aurélien Núñez
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Aurélien Nuñez is a Functional and micronutritional Medical Doctor, graduated from the Favaloro University of Buenos Aires, Argentina. Specialised in Micronutrition, Food, Prevention and Health (MAPS) from the Paris Descartes University. He is working at Hotel Capela Das Artes in a project named Smart Treatments, where with his colleague, Silvestre Gonzalez, an Ayurveda-oriented Medical Doctor, and a team of therapists, are offering consultations, body therapies, retreats, yoga, meditation classes and workshops.