Polyphenols are a group of plant chemicals that contribute to the vibrant colour, taste and aroma of many fruits, vegetables and flowers. They range in colour from emerald-green, golden-yellow and vivid orange to brilliant red, deep purple, snow-white, even colourless. More importantly for us, polyphenols wield a rich cornucopia of known and as-yet-to-be-discovered health benefits, many of which have vitamin-like importance. Mark my words, numerous polyphenol compounds will in the future be recognised as vitamins – i.e. compounds that are essential for health which cannot be synthesised (at least typically) by the body, so must be provided dietarily. In fact, many European scientists and researchers already refer to Polyphenols as Vitamin P, a moniker that was actually coined by the Nobel Prize-winning physiologist Albert Szent-Gyorgyi, who also discovered vitamin C.
When I think of polyphenols, there is one astonishing food that always comes to the forefront of my mind. Curiously, the food in question is the unopened flower bud of a hardy, spiky Mediterranean plant (Capparis Spinosa). The buds are picked when they are the size of peas and are known in English as capers, and in Italian as capperi. Capers typically grow in hot, arid regions across the Mediterranean, usually on sun-baked cliffs and rocky hillside terraces with fast draining soils. As a result, of these harsh climatic conditions, capers have developed unusually high levels of antioxidant polyphenols to protect their leaves and flower buds from high levels of ultraviolet radiation, searing temperatures and drought. As a result, capers have one of the highest polyphenol contents of any food, providing an astonishing 3600mg polyphenols per 100g. To succinctly explain why this is so, I want to introduce you to the concept of Xenohormesis.
Xenohormesis is the idea that plants under environmental stress produce survival compounds that, when consumed by humans, impart comparable adaptive responses within our own physiologies. These compounds activate our own cellular defence and repair systems, activate longevity pathways like SIRT1, and improve mitochondrial functionality. By contrast, the majority of cultivated plants are highly domesticated varieties that have been grown, for many generations, in overly "mollycoddled" environments - lower in natural UV radiation, with regular water, fertiliser, commonly protection from pests, perhaps grown in polytunnels, the accumulation of which, keep Xenohormetic compounds in much lower ranges. In short, the polyphenol concentrations of most conventional agricultural products is much weaker because they have not historically been challenged to nearly the same degree.
Native and wild Mediterranean botanicals like capers, on the other hand, must survive intense sun and UV, salinity and wind, often poor soil (as is the case when bushes grow out of rocky outcrops), and extreme temperatures. As a result, they develop a richer, more potent phytochemistry and revered medicinality: from wild rosemary and oregano on rocky windswept coasts, to sunbaked, drought-resistant olives (and the oils thereof), to wild bilberry and sea buckthorn berries, chaga and reishi mushrooms thriving against long, hostile Winters, from wild seaweeds, pummelled by wind, wave, intense UV and extreme salinity, to high altitude root vegetables like maca or Jerusalem artichoke, having to adapt to life on the edge. These Xenohormetic rich botanicals are not just antioxidants, they are messengers, training our body how to endure, repair, and thrive under pressure; they are teaching us how to overcome. These remarkable plants and fungi survive through adaptation. When we consume them, we do too.
Ok, so going back to capers. Capers are the richest known source of the master polyphenol quercetin (or as I like to say, Vitamin Q), a plant compound which exhibits, among so many other aptitudes, extremely promising capacities as an anti-aging (or anti-senescence) chemical, especially as a powerful scavenger of the oxidation process. Compared to broccoli (a food commonly cited as being a rich source) capers have over 70 times the quercetin levels per 100g (i.e. 3mg compared to the 235mg that capers offer). Caper buds are also the richest known source of rutin. Rutin is a highly acclaimed polyphenol with numerous longevity-promoting actions, perhaps, most famed of all, for its ability to strengthen the cardiovascular system and stabilise collagen and elastin in blood vessel walls, whilst protecting them from oxidative damage. Compared to common buckwheat (a food commonly cited as being a rich source) capers have over 10 times the rutin levels per 100g (i.e. 25-30mg compared to the 320mg that capers offer).
While, the extremely high polyphenol content of capers was only recognised fairly recently, researchers from around the world are already building an impressive list of their beneficial capacities in vivo . Zooming out a little further from their incredible quercetin and rutin content, capers are being highlighted for their promise in a wealth of different areas, including:
Capers for skin inflammation: just as the caper’s polyphenols protect the plant of ultraviolet radiation, caper extracts are used in medicinal creams to prevent photo-ageing, spider veins, and to treat inflammatory conditions such as rosacea. Eating them regularly also allows these compounds to naturally build up in the skin and underlying blood vessels.
Capers for allergies: The high levels of quercetin and rutin in capers can suppress allergic reactions in a number of ways, including reducing histamine release, the formation of IgE antibodies, and restoring normal immune responses away from abnormal allergic reactions towards those that fight infection.
Within the skin, capers can reduce symptoms of atopic dermatitis, contact dermatitis and eczema, and numerous high-end cosmetic formulas use them in some form. Research suggests that quercetin is more effective than the drug, cromolyn, in stabilising mast cells that release histamine and trigger allergic symptoms. Many people find quercetin helpful in reducing allergy symptoms such as hayfever, mold allergy and histamine intolerance.
Capers for cancer protection: Capers are used in traditional Chinese medicine to support cancer treatment. Researchers have found that capers have a natural anti-tumor activity by triggering the body’s own mechanism for destroying abnormal cells (a process known as apoptosis). This process involves the energy-generating mitochondria found within cells. A protein with anticancer, antiviral and antifungal activity has also been identified from caper berries.
Capers for your heart and vessels: Capers are rich in rutin and other flavonoids, which strengthen blood vessel walls, improve endothelial function, and reduce capillary fragility. Their antioxidant and anti-inflammatory properties help lower oxidative stress and support healthy blood pressure and lipid profiles. Regular consumption contributes to cardiovascular protection and overall vascular health.
Capers for diabetes: Caper berry extracts can lower fasting blood glucose levels in people with type 2 diabetes. Their antioxidant action was also found to significantly reduce blood levels of glycosylated haemoglobin (HgA1c) compared to those taking an inactive control. Caper extracts also improved triglyceride levels in people with diabetes.
Capers for arthritis: Capers are a traditional anti-inflammatory medicine used to relieve the pain and stiffness of rheumatism and arthritis. Cell culture studies show that caper extracts have a greater protective effect on joint cartilage cells than the non-steroidal anti-inflammatory drug, indometacin.
Capers for longevity: Capers are extremely rich in compounds with strong antioxidant activity that scavenge free radicals and reduce oxidative stress, one of the central mechanism linked to aging and chronic disease. Preclinical evidence shows that capers can modulate inflammatory and neurodegenerative pathways, including down‑regulating inflammation‑related gene expression in Alzheimer’s models, suggesting potential neuroprotective effects.
Capers for depression and memory: Initial investigations suggest that caper extracts have beneficial effects in combatting depression and improving learning and memory.
Capers epitomise the notion of food as medicine and are one of the simplest, most effective ways of boosting your Vitamin P levels and staying ahead of the health-curve. Most commercially-available capers are unfortunately pickled in cheap table salt brine water (usually just filtered tap water) alongside other common preservatives such as citric acid, sodium benzoate and synthetic vinegar. For the very highest-quality direct-from-farm capers, traditionally packed in natural sea salt, I am delighted to bring to market these genuine Protected Designation of Origin offerings right here.
Kyle Vialli (2026)
