As we age there is a known decline of physical strength that occurs, but research now suggests that there is also a decline in cellular strength that leads to a declined immune response. Research also suggests that aging negatively alters the impact of nutrition on immune function and response in both healthy and at-risk ageing individuals. This phenomenon can be described as immunosenescence and is the irreversible progressive decline in immunity, poor response to vaccination and increased prevalence of illness. (1) Influenza is one of the major causes of death in the ageing population, and now COVID-19 seems to have more negative effects on this population than in younger populations. One of the impairments that occurs is in the immune cells in your gut microbiota and involves probiotics. The gut microbiota plays an important role in your body’s immune system. It keeps up the population of beneficial microbes and reduces the dangerous pathogens to keep you healthy. The gut microbiota also plays a role in the inflammatory cells in your body, regulating their production so you have a balance between pro-inflammatory and anti-inflammatory cells. Probiotics are living microorganisms that help keep our gut microbiota healthy and are found in foods like yogurt and cheese. But research shows that as you age your gut microbiota function is reduced and your body responds less to probiotics, so you need to consume more for them to function at the same level as when you were younger. (2) This decline in one of the main mechanisms keeping you healthy leads to more infection from illness as you get older. Another immune impairment that occurs as you age is in the regulation of your immune memory cells, called T cells. T cells help to remember pathogens they’ve come into contact with before to kill them quicker and signal to other immune cells to join the immune response. (3) As we age the ability of these T cells to signal for help in fighting an infection declines, so our cellular response to a pathogen is slower, leading to prolonged infection times. (1) While the idea that the elderly are more susceptible to illness is nothing new, even during the 1918 Spanish Flu outbreak health officials knew that it affected those over 65 worse than any other population, the way that infection affects them cellularly is still a widely debatable topic and more research is needed in this area. The best way for ageing populations to stay healthy is to eat a balanced diet (and make sure probiotic rich foods are included daily) and to practice regular moderate intensity exercise to induce as many positive immune changes that they can in case they ever do come into contact with an illness.
1. Yoqoob, P. Ageing alters the impact of nutrition on immune function. Preceedings of the Nutrition Society. 2017;76(3):347-351. doi:10.1017/S0029665116000781
2. You J & Yaqoob P. Evidence of immunomodulatory effects of a novel probiotic, Bifidobacterium longum bv infantis CCUG 52486. FEMS Immunol Med Microbiol. 2012;66, 353–362.
3. Information NC for B, Pike USNL of M 8600 R, MD B, Usa 20894. The Innate and Adaptive Immune Systems. Institute for Quality and Efficiency in Health Care (IQWiG); 2016. Accessed May 4, 2020. https://www.ncbi.nlm.nih.gov/books/NBK279396/