The immune system can be strengthened by correcting one’s diet for variety and balance. In this regard, polyphenols play a valuable role due to their antioxidant and protective functions highlighted in the brief scientific review to follow. Attached to which is a table of the vegetables that are richest in these ‘natural medicines’.
Polyphenols and health
Polyphenols are found in a wide variety of plant foods including fruits, vegetables, soybeans, tea and cocoa. They are compounds specific to plant secondary metabolism and exert defense functions (phytonutrients) of the very plant organisms that produce them. It is a large family, about 5,000 naturally occurring organic molecules, divided into (at least) seven families and characterized by the presence of multiple phenolic groups, which are associated in structures of even remarkable size and molecular weight. (1,2) Their effect is often referred to as ‘antioxidant’ for simplicity’s sake, although their functions are also others. And it is therefore that various tea, coffee and bitter chocolate drinks are often related to antioxidant properties. (1-8).
From a health perspective, the interest in polyphenols is first and foremost related to the inverse relationship between the intake of foods rich in these compounds (Tables 1 and 2) and the incidence of serious and chronic diseases (cardiovascular disease, diabetes, and cancer in particular). Their favorable interaction with the gut microbiome also suggests their beneficial role for the immune system. It should also be borne in mind that the scientific tests performed to date are largely derived from experiments conducted in vitro, or on animal models, using often large amounts of substances.
Health benefits proven by science
The general function of polyphenols is to protect the body from cell oxidation (lipid peroxidation). An antioxidant function, which scientific research has shown to produce a number of beneficial effects on human health. These include the capabilities of:
– Inhibit the proliferation of cancer cells,
– Modulate some critically important enzymes,
– Reduce cholesterol absorption. Resulting in relief to the cardiovascular system). (1-11)
Additional benefits associated with the intake of these substances include:
– antibacterial action. Flavanols (catechins) in green tea are often ascribed to be effective against foreign bacteria. Favoring the development in the gut microbiota of ‘friendly’ and probiotic bacteria (such as Klebsiella, enterococci and bifidobacteria), at the expense of others. (12)
– stimulation of the immune system. Polyphenols are the most relevant dietary source of special receptors(Aryl hydrocarbon Receptors, AhRs) that activate and enhance the response of the immune system as a whole. (13-14)
Foods rich in polyphenols
The human organism, it should be noted, does not synthesize this family of substances found precisely in plant organisms. It is therefore necessary to ensure their bioavailability by consuming foods that are rich in them every day-and several times a day. So that these ‘natural medicines’ can exert their beneficial functions on the systems, organs and tissues that need them.
The tables below indicate unprocessed plant foods (Table 1) and those transformed (Table 2) Where these substances are found in larger quantities.
Salvatore Parisi and Dario Dongo
Sources
(1) Salvatore Parisi. (2019). Analysis of Major Phenolic Compounds in Foods and Their Health Effects. Journal of AOAC International, https://doi.org/10.5740/jaoacint.19-0127
(2) Singla RK, Dubey AK, Garg A, Sharma RK, Fiorino M, Ameen SM, Haddad MA, Al-Hiary Masnat (2019). Natural Polyphenols: Chemical Classification, Definition of Classes, Subcategories, and Structures. J AOAC Int, https://doi.org/10.5740/jaoacint.19-0133
(3) Delgado, AM, Issaoui M, Chammem N. (2019). Analysis of Main and Healthy Phenolic Compounds in Foods. J AOAC Int, https://doi.org/10.5740/jaoacint.19-0128
(4) Bhagat AR, Delgado AM, Issaoui M, Chammem N, Fiorino M, Pellerito A, Natalello S. (2019). Review of the Role of Fluid Dairy in Delivery of Polyphenolic Compounds in the Diet: Chocolate Milk, Coffee Beverages, Matcha Green Tea, and Beyond. J AOAC Int, https://doi.org/10.5740/jaoacint.19-0129
(5) Barbieri G, Bergamaschi M, Saccani G, Caruso G, Santangelo A, Tulumello R, Vibhute B, Barbieri G. (2019). Processed Meat and Polyphenols: Opportunities, Advantages, and Difficulties. J AOAC Int, https://doi.org/10.5740/jaoacint.19-0134
(6) Zugravu C, Otelea MR. (2019) Dark Chocolate: To Eat or Not to Eat? A Review. J AOAC Int, https://doi.org/10.5740/jaoacint.19-0132
(7) Laganà P, Anastasi G, Marano F, Piccione S, Singla RK, Dubey AK, Delia S, Coniglio MA, Facciolà A, Di Pietro A, Haddad MA, Al-Hiary M, Caruso G. (2019). Phenolic Substances in Foods: Health Effects as Anti-Inflammatory and Antimicrobial Agents. J AOAC Int, https://doi.org/10.5740/jaoacint.19-0131
(8) Parisi S (2020) Characterization of Major Phenolic Compounds in Selected Foods by the Technological and Health Promotion Viewpoints. J AOAC, in press
(9) Barbera M (2020) Reuse of Food Waste and Wastewater as Source of Polyphenolic Compounds to Use as Food Additives. J AOAC, in press
(10) Issaoui M, Delgad AM, Caruso G, Micali M, Barbera M, Atrous H, Ouslati A, Chammem N (2020) Phenols, Flavors, and the Mediterranean Diet. J AOAC, in press.
(11) Haddad MA, Abu-Romman S, Obeidat M, Iommi C, El-Qudah J, Al-Bakheti A, Awaisheh S, Jaradat DMM (2020) Phenolics in Mediterranean and Middle East Important Fruits. J AOAC, in press
(12) Kemperman, R. A., Gross, G., Mondot, S., Possemiers, S., Marzorati, M., Van de Wiele, T., et al. (2013) Impact of polyphenols from black tea and red wine/grape juice on a gut model microbiome. Food Res. Int. 53, 2:659-669
(13) Palestini P, Dongo D (2020). Coronavirus, how to strengthen the immune system. Nobel Montagnier and the scientific evidence. https://www.greatitalianfoodtrade.it/salute/coronavirus-come-rafforzare-il-sistema-immunitario-il-nobel-montagnier-e-l-evidenza-scientifica
(14) Xue, Z., Li, D., Yu, W., Zhang, Q., Hou, X., He, Y., & Kou, X. (2017) Mechanisms and therapeutic prospects of polyphenols as modulators of the aryl hydrocarbon receptor. Food & function, 8(4), 1414-1437.
(15) Turco I (2017) Nutrition and health: Role of polyphenols in legumes in the prevention of dysmetabolic diseases. Dissertation, Marche Polytechnic University
(16) DíEvoli L., Azzini E., Lucarini M., Aguzzi A., Gabrielli P., Venneria E., Foddai M.S., Durazzo A., Lombardi-Boccia G. (2013). Two quality horticultural products: Radicchio Rosso di Treviso and Radicchio di Castelfranco (Cichorium intybus L.). Biodiversity and agribusiness: tools to describe the Italian reality, 11
(17) Gestri S (2008) Analysis of polyphenols as in vitro inhibitors of amyloid-type aggregation. Dissertation, University of Florence
(18) Zhang J, Zhan B, Yao X, Gao Y and Shong J (1996) Antiviral activity of tannin from the pericarp of Punica granatum L. against genital herpes virus in vitro. Zhongguo Zhong Yao Za Zhi 20(9): 556-8, 576
Dario Dongo, lawyer and journalist, PhD in international food law, founder of WIISE (FARE - GIFT - Food Times) and Égalité.
He has been dealing with chemistry and food, packaging and quality for over 20 years. 'Visiting Assistant Professor' at Al-Balqa Applied University (Jordan), as well as 'Expert Review Panelist' in the working groups of AOAC International (USA) and 'Series Editor' for the series 'SpringerBriefs in Molecular Science: Chemistry of Foods'
