Philip Calder is Head of the School of Human Development and Health and Professor of Nutritional Immunology in the Faculty of Medicine, University of Southampton, Southampton, UK. He is an internationally recognized researcher on the metabolism and functionality of fatty acids, with an emphasis on the roles of omega-3 fatty acids, and on the influence of diet and nutrients on the immune and inflammatory responses. His research addresses both life course and translational considerations and includes research in cell and animal models and in healthy humans and patients. He has received many awards and prizes for his work including the American Oil Chemists’ Society Ralph T. Holman Lifetime Achievement Award (2015), the prestigious Danone International Prize for Nutrition (2016) and the DSM Lifetime Achievement Prize in Human Nutrition (2017). Professor Calder was President of the International Society for the Study of Fatty Acids and Lipids (2009-2012), Chair of the Scientific Committee of the European Society for Clinical Nutrition and Metabolism - ESPEN (2012-2016) and President of the Nutrition Society (2016-2019). He is currently President of the Federation of European Nutrition Societies (2019-2023). Professor Calder was Editor-in-Chief of the British Journal of Nutrition (2006-2013) and is currently an Associate Editor of Journal of Nutrition, Clinical Science, Nutrition Research and Annals of Nutrition and Metabolism. He has over 700 scientific publications and is recognized as a Highly Cited Researcher.
The key roles of the immune system are the identification of pathogens, their elimination and the generation of immunologic memory. Human infants are born with an immature immune system that matures over the first months to years of life. At the other end of the life course, the immune system can decline with age. Thus, both early and later life are times of “immune weakness” and vulnerability to infection. Many factors influence the functions of cells of the immune system, including nutritional state. Both frailty and obesity weaken the immune response, impairing the response to vaccination and increasing susceptibility to infection. Older people, especially those who are frail, are at greater risk of severe COVID-19 and mortality than younger adults. Likewise, obesity increases risk of more severe COVID-19. Micronutrients and other essential nutrients are vital for supporting immune cell metabolism, for biosynthesis and cellular proliferation, for regulation of molecular and cellular responses, and for protection against the oxidative and inflammatory stress the immune response causes. Vitamins A, B6, B9 (folate), B12, C, D, E and zinc, selenium, iron and copper (and others) have all been demonstrated to support the immune system to function. Some micronutrients have specific antimicrobial or antiviral activities. Supplementation trials, often using higher intakes than can be achieved from the diet, have shown that several micronutrients can enhance immune responses and in some cases this is associated with decreased risk of infections, including respiratory infections. The coronavirus pandemic has stimulated interest in several micronutrients and antiviral immunity.