They are plant compounds found in a wide range of foods, giving bright colours to many fruits and vegetables. Their antioxidant properties are renowned, as they neutralise harmful free radicals that damage our cells and increase the risk of conditions such as cancer, diabetes, and heart disease. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3614697/
Polyphenols are found in higher concentrations in fruits, vegetables, nuts, spices, beverages (tea and cocoa), whole grains, with extra virgin olive oil being the most important source.
They shield the immune system
A strong immune system is the result of a balanced lifestyle, a large and integral part of which is nutrition. Polyphenols improve the interaction between immune system cells and reduce the generation of pro-inflammatory cytokines.
At the same time, polyphenols have been shown to enhance anti-cancer immune activity, as well as immunomodulatory processes and immunity of the gut microbiome. The complex way in which polyphenols respond positively to the prevention and treatment of several diseases, shielding our immune system will be explained in detail below.
Protect against cardiovascular disease
Modern lifestyles are harmful to our heart health. Several studies have proved that polyphenols reverse the damage in multiple ways:
By lowering levels of "bad" cholesterol, they protect blood lipids from oxidative stress. In this way, they also reduce the risk of atherosclerosis, which in turn causes strokes and heart attacks.
They have been shown to regulate blood pressure, making them particularly beneficial for people with hypertension.
They inhibit the accumulation of platelets and improve endothelial function to reduce the formation of a haemostatic plug that causes thrombosis, strokes, and serious respiratory problems.
They protect the nervous system
Brain and nervous system dysfunctions have been shown to be linked to intestinal dysbiosis and to gut microbiome problems. Thus, gut regulation using polyphenols paves the way towards new treatments and interventions in neuropathologies, leading to partial or complete reversal of specific diseases, but also preventing their occurrence proactively.
Recent years have seen a breakthrough in the understanding of glial cell functions. Astroglial cells, originally thought to be exclusively neuronal support cells, are now recognised as cells vital for the functional control of the nervous system. Glial cell dysfunction has recently been linked to various brain diseases, and research has shown that certain flavonoids, which are the largest class of polyphenols, increase glial cell secretion and levels in the brain, thus protecting our health.
The search for new therapeutic solutions that promise to address the multidimensional features of Parkinson's disease is ongoing, and it appears that polyphenols exhibit soothing properties in its treatment. It has been documented that oxidative stress and inflammation are important factors that accelerate the process of neurodegeneration that gives rise to Parkinson's disease
In research examining the parameters of oxidative stress, including oxidative damage to key cellular macromolecules, polyphenols were shown to be able to counteract oxidative damage in the striatum, acting as a mound in the progression of the disease. At the same time, polyphenols have been shown to restore the reduced activities of protein kinase C (PKC), which play an essential role in programmed cell death and cell survival, thus inhibiting the apoptosis defined by Parkinson's disease.
They improve allergic symptoms
Allergic conditions can become particularly troublesome at the onset of their symptoms. Polyphenols have been shown to have significant benefits in three allergies that are common to many people around us - if not ourselves: asthma, food allergies and eczema. Not only do polyphenols reduce the intensity of symptoms, but they also prevent the development of allergies, giving a better quality of life.
Through research, it has been shown that the interaction of polyphenols with proteins modulates the process of allergic sensitisation, and this direct effect on allergic cells, such as mast cells, inhibits the release of mediators, resulting in symptom relief. In addition, their proven endogenous antioxidant capacity limits the extent of cellular damage by free radicals during an allergic attack.
Control blood sugar levels
The miraculous properties of polyphenols include regulating blood glucose levels, making them a magic ingredient for both preventing type II diabetes and for patients suffering from the disease.
Both genetic and environmental risk factors, such as inappropriate eating habits or physical inactivity, are known to play a key role in the development of type 2 diabetes.
A pooled analysis of large studies proved that a healthy diet rich in whole grains, fruits, vegetables, nuts, legumes, vegetable oils and olive oil was associated with a significantly lower risk of type 2 diabetes. In addition, as demonstrated in a large analysis including data from more than 300 thousand patients, a diet that is rich in polyphenols has been proven to be beneficial for the primary prevention of type 2 diabetes. Similarly, at least five other large studies reported a significantly lower risk of type 2 diabetes in healthy individuals or individuals at immediate risk who consumed a Mediterranean diet. 500 mg of flavonoids (the largest class of polyphenols) per day is associated with a significant reduction in the risk of type 2 diabetes.
Numerous studies confirm that polyphenol intake may be beneficial as an adjuvant therapy for the prevention and treatment of chronic diseases that cause inflammation. The action of oleocanthal, one of the polyphenols that resembles the chemical composition of ibuprofen or aspirin, blocks the pathways of inflammatory diseases, and shields our body.
At the same time, thanks to oleocanthal, a significant contribution of polyphenols has been observed in the treatment and prevention of multiple sclerosis. Research data have shown that polyphenols can inhibit the nerve inflammation and damage that causes MS, with this dynamic mode of action giving them therapeutic properties in the fight against this serious disease.
Slow down ageing
Ageing is a proven risk factor for a wide range of diseases, including neurodegenerative diseases. In addition, the cellular inflammatory response of cells increases progressively with age, which increases the risk of developing chronic inflammation-related diseases. Increasing evidence shows that senescent cells accumulate in tissues, and the accumulation of senescent cells is also associated with ageing-related diseases such as diabetes, atherosclerosis, and obesity. Interestingly, oxidative stress has been shown to be one of the main factors in cellular ageing. Therefore, polyphenols with their antioxidant activity may have the potential to prevent cellular ageing. However, their anti-aging properties are even more direct, as a diet rich in polyphenols has been found to help combat metabolic and degenerative diseases associated with ageing, in defiance of the modern lifestyles.
Shield the digestive system
Modern lifestyles and diets are proving to be particularly damaging to our digestive system, leading to several problems. A diet rich in polyphenols contributes to the production of peptides that help in the absorption of nutrients and balances the bacteria in our digestive tract, stimulating the growth of "good" bacteria in the gut and reducing the number of "bad" ones.
Research has shown that the gut microbiome and polyphenols influence each other.
The gut microbiota and dietary polyphenols influence each other: the microbiota enzymatically transforms polyphenols improving bioavailability and health effects, while polyphenols shape the composition of the microbiota community avoiding the growth of pathogens.
This is because, in fact, polyphenols can modify the composition and functions of the microbiome by acting on its metabolism. Adults undergo dramatic changes in the composition of the microbiome. In addition, ageing is associated with specific changes in the diversity of the microbiome, which result in negative health consequences as we move into middle and old age. It is becoming clear that polyphenols contribute to maintaining our proper digestive function by modulating the gut microbial balance by enhancing the growth of beneficial bacteria and inhibiting the growth of pathogenic microorganisms - much like probiotics.
They have strong antioxidant activity
Polyphenols are natural antioxidants that exhibit higher antioxidant activity, lower toxicity and other advantages over traditional synthetic chemical drugs that are often suggested for their antioxidant activity.
Authoritative animal and human studies, as well as epidemiological studies, have shown that polyphenols have antioxidant and anti-inflammatory properties that could have preventive and therapeutic effects on cardiovascular diseases, neurodegenerative disorders, cancer, and obesity.
The obesity epidemic and its steady increase over the last decades in the Western world is one of the biggest medical issues worldwide.
Not only does olive oil consumption not seem to increase the likelihood of weight gain, but it may even help with weight loss and ultimately obesity. This is thanks to several mechanisms that contribute to lipid and energy metabolism, thus facilitating the prevention of weight gain.
More specifically, a few studies have proved that dietary polyphenols prevent the development of obesity and contribute to its management through the following six mechanisms: 1) reducing food intake; 2) reducing lipogenesis; 3) increasing lipolysis; 4) stimulating beta-oxidation of fatty acids; 5) inhibiting adipocyte differentiation and growth; and 6) mitigating inflammatory responses and suppressing oxidative stress.
They have strong anti-cancer properties
It has been shown that polyphenols can exert anti-cancer effects through a complex range of mechanisms, including the removal of cancer cells and inhibition of cell cycle events. Polyphenols also regulate the activities of enzymes involved in the proliferation of cancer cells by slowing down or interrupting their function. They thus inhibit tumor growth.
- The research carried out on the contribution of polyphenols in the fight against leukaemia is extremely encouraging. Thanks to their complex molecular mechanisms, polyphenols target various molecular pathways that lead to cell cycle inhibition and force leukaemia cell lines into apoptosis. At the same time, the way polyphenols directly target pro-inflammatory pathways may also have anti-cancer effects in the treatment of leukaemia. What is certain is that even though further investigation is needed, the research to date agrees that polyphenols can be considered as a therapeutic approach for the treatment of leukaemia, either alone or combined with chemotherapeutic agents, although antagonistic actions also need to be investigated
- Polyphenols also appear to be beneficial in the treatment of melanoma. The skin is the largest organ of the body, and its main role is to act as a natural bulwark in protecting the internal organs from the effects of various harmful substances. Regular exposure to harmful radiation, however, makes its mission more difficult, with skin cancers becoming increasingly common. Studies have proved that polyphenols can actively inhibit the proliferation of cancer cells, which represents an important biological process in the development of tumors.
- In men, prostate cancer is the second most common malignancy after lung cancer, with modern lifestyles exacerbating the occurrence of the disease. Research carried out on the molecular mechanisms’ properties of polyphenols in prostate cancer demonstrates that polyphenols can inhibit its neoplastic processes, such as proliferation, invasion, metastasis, or angiogenesis. Polyphenols, therefore, demonstrated their antioxidant activity through two ways: first, they act as radical scavengers to prevent cellular damage produced by reactive oxygen species (ROS) and second, they act as molecules that prevent the generation of these reactive oxygen species. Polyphenols act as preventive agents in prostate cancer, mainly due to their antioxidant or pro-oxidant effects. In addition, they influence cell cycle arrest and apoptosis. In addition, polyphenols have been shown to be beneficial against tumor invasion through inhibition of angiogenesis and metastasis. Further and thorough research should be carried out regarding this association, but polyphenols are beneficial in the prevention and treatment of prostate cancer.
- Breast cancer has the highest cancer diagnosis rate among women, making it a real scourge. The link between a good diet and the prevention of breast cancer, as well as the general reduction in the incidence of health-threatening diseases, has been proven through research and is largely attributed to the beneficial effects of polyphenols. They have been shown to have a preventive effect against the development of tumors through numerous mechanisms, such as preventing the formation of genotoxic molecules and inhibiting the activity of enzymes that transform mutagens to favor the development of cancer. During carcinogenesis, there is an imbalance between the action of cell cycle progression proteins and cell cycle arrest proteins, resulting in intense cell division and proliferation. Cell cycle progression may be mediated by cyclins and cyclin-dependent kinases. Research has shown that cancer cells treated with polyphenols have been shown to exhibit down-regulation of cyclins and cyclin-dependent kinases, leading to an interruption of the cell cycle responsible for proliferation. Although further research remains to be conducted, the therapeutic applications of polyphenols in breast cancer are already promising.
- The major pathological processes of liver diseases - among which liver cancer is one of them - are oxidative stress, lipid peroxidation, inflammation, and impaired immune response. At the same time, polyphenols have been found to have a variety of pharmacological effects on oxidative stress, lipid metabolism, insulin resistance and inflammation. Studies have demonstrated that many polyphenolic compounds have shown remarkable properties in promoting apoptosis and suppressing the proliferation of liver cancer cells through various pathways, and a growing number of studies have proved that a variety of polyphenols could inhibit both invasion and metastasis in liver cancer. The need for future studies to further evaluate the effect of polyphenols in the fight against liver cancer is imperative, but the early evidence is overwhelmingly in their favor.
They have effective antimicrobial action
We live in a time when fighting germs and the infections they cause is a major issue. So, it seems that polyphenols also help us significantly in shielding our body against microbial infections. Through research, it has been found that they have antibacterial activity against many bacteria and fungi, and some of the studies have proved that polyphenols work combined with antibiotics, offering a holistic protection of our body. In particular, numerous studies have demonstrated the powerful antibacterial properties of polyphenolic compounds and extracts rich in these molecules against the Staphylococcus aureus microbe.
As antibiotic resistance is becoming a global problem, finding new ways to fight the microbes becomes imperative. Polyphenols and polyphenol-rich extracts are proving to help as an effective solution, as more and more studies are now reporting their antimicrobial activity against most pathogens.
At the same time, another study thoroughly examined the antibacterial activities of polyphenols against five common pathogenic bacteria: Staphylococcus aureus, the parasitic Donacillus that causes gastrointestinal issues, Escherichia coli, Salmonella and Enterobacterium. The results proved that the antibacterial performances of polyphenols are beneficial, although reduced in cases of hyperglycemia due to the possible suppression of their antibacterial benefits, thus calling for a holistic view of our life and nutrition and the integration of polyphenols within this new daily routine.
Similarly, Helicobacter pylori infection affects more than half of the world's population and, with around 10 to 20% of sufferers suffering from peptic ulcers, which can eventually lead to gastric cancer. As the main characteristic of polyphenols is their antioxidant activity targeting the immune system cells. Research proves that the consumption of polyphenols contributes to the maintenance of gut health through their stimulating effects on the growth of beneficial bacteria and the inhibition of pathogenic bacteria, actively slowing down the host's metabolism. Even if further research proving the therapeutic effect of polyphenols on Helicobacter pylori infection is deemed necessary, everyone agrees that they can be seen as a new and safe alternative treatment for this chronic disease.
Promote bone and joint health
There have been several studies confirming that the combination of polyphenolic compounds reduces the risk of osteoporosis by increasing bone density, while providing protection against bone damage caused by oxidative stress during intense exercise.
The evidence doesn't lie. Rheumatoid arthritis is a chronic, systemic, autoimmune inflammatory disease that affects the joints, with the percentage of patients with the disease increasing rapidly so that symptom management is a major concern for patients around the world. Research has proved that polyphenols reduce the symptoms of rheumatoid arthritis by regulating an extensive collection of molecules associated with the onset of the disease. Even though further studies are needed to clarify the antioxidant and effects of polyphenols and the ways they regulate the pathogenic pathways of rheumatoid arthritis, the early evidence is more than encouraging and encourages us to add them to our diets.
Preventing brain disorders and promoting our mental health
The benefits of polyphenols are not limited to our physical well-being. One of the most important and multiple benefits of polyphenols relates to their beneficial effect on brain function while fighting mental illnesses. Polyphenolic compounds are involved in shaping mental health, including brain plasticity, behavior, mood, depression, and cognition, preventing Alzheimer's disease and dementia, as well as attention-deficit/hyperactivity disorder. Significantly, in research studies, after 8 weeks of contextual consumption of polyphenols, participants' attention, memory, executive functions, and mood assessment showed marked improvement.
The direct intervention of polyphenols in the pathophysiology of schizophrenia and its treatment has not yet been thoroughly investigated, however, the increased oxidative stress it causes has been shown to be inhibited by several polyphenolic compounds.
As you can see, polyphenols are a miraculous ingredient that can solve many problems caused by modern lifestyle, thus shielding our body. At the same time, they are the most crucial ingredient of a balanced lifestyle that highlights the benefits of the Mediterranean diet. We believe that polyphenols are the secret to an alternative and healthier daily life. And with Holiston, we offer a solution to modern problems that goes beyond medication, proposing a meaningful opportunity for well-being!