How to Rejuvenate Your Immune System

Whatever you think about the lifting of coronavirus restrictions, our immune systems are about to be put to the test again.

Our immune system is a complex biological network that protects our bodies from viruses and disease, but like all systems it weakens with age. Our immune cells become less effective at hunting down invaders and start to misfire, causing damage, which is why people over 70 are more vulnerable to viruses and diseases.


This decline in immunity happens to us all, but now scientists are discovering how our lifestyles can speed up or slow down the rate at which it does. Obesity, stress and behaviours such as smoking can raise your immune age, while healthy changes can turn back the clock and lower it, reducing our risk of serious illness and helping you live longer.


In other words, a 35-year-old can have the immune system of a 50-year-old, or a healthy 60-year-old could have that of a much younger adult.


“Our immune systems age just like the rest of us,” says Dr Jenna Macciochi, a leading expert in immunology at the University of Sussex and author of Immunity: The Science of Staying Well. “However, recent studies have found that our ‘immune age’ isn’t necessarily the same as our chronological age.”


So, how to rejuvenate your immune system and turn back the chronological clock? Here are some recommendations:


Exercise: Studies show regular exercise in old age can prevent a decline of the immune system. One 2018 paper from King’s College London followed 125 long distance cyclists, some in their 80s, and found they had the immune systems of 20-somethings. “If exercise was a pill, everyone would be taking it,” said Prof Norman Lazarus, then 82, who took part in and co-authored the research.


Research in the British Medical Journal found those who walked for at least 20 minutes a day had 43 percent fewer sick days due to the common cold.


Look after your muscles, too - strength training has been shown to have the effect of sheltering certain types of T-cells, important in our immune response.


Eat more protein: Evidence shows that poor gut health can increase immune age, says Dr Macciochi, while a healthy microbiome can slow down the ageing process. “Aim to eat as many different plant foods as possible. I also have protein with every meal because this supports the antibodies needed by your immune system.” Slow fermented sourdough bread is good for gut diversity, as is seasonal fruit and vegetables, whole grains and legumes.


According to a 2018 review on diet and immune ageing, adequate protein is important for effective immune responses.


A study of 120 older adults found that a Mediterranean diet, high in vegetables, fruit, pulses, wholegrains, oily fish and olive oil, had a positive impact on ageing immune cells.


Cold showers: Exposure to cold temperatures stresses the immune system in a beneficial way, creating an anti-ageing effect. A study in the journal PLoS One found people who take cold showers are 29 per cent less likely to call in sick for work. “At the end of every shower, turn the temperature to the coldest setting for 20 or 30 seconds,” advises Dr Macciochi.


Get outside and take vitamin D: Vitamin D’s role in immunity is now well established. Experts agree that we should spend plenty of time outside and take supplements between October and March. “I’m often asked about dietary supplements, but I don’t think they’re particularly helpful,” says Professor Charles Bangham, chair of immunology at Imperial College London. “One exception is vitamin D."


Sleep: When we’re asleep, our immune system releases proteins called cytokines, which we need to fight infection or inflammation in the body or to cope with stress. A lack of sleep can decrease production of these cytokines, as well as infection-fighting antibodies. “Sleep is the bedrock of your immune system,” says Dr Macchiochi. “If you don’t sleep properly, other immune-protecting behaviours during the day like eating well and exercise won’t really count.”


Socialise: “Social connections have been found to be important in immune ageing,” says Dr Macciochi. “When we feel lonely, however, our immune systems go on high alert and an inflammatory response takes place.” So while a return to the pub or office may feel daunting, it could actually give your immune system a boost.

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