Health and fitness: Anti-age your immune system — here’s how to turn back the clock
Our ability to fight off illness starts declining in our twenties, but you can reverse the trend with simple diet and exercise changes
As with nearly everything else to do with our bodies, the effectiveness of the immune system declines with age.
From our twenties onwards the body’s ability to fight infection decreases at a rate of about 2 to 3 per cent a year, gradually leaving us more susceptible to diseases, says Janet Lord, a professor of immune cell biology and the director of Birmingham University’s Institute for Inflammation and Ageing.
But, she says, the speed at which this happens isn’t unavoidable. “Ill health should not be an inevitable part of growing old. By understanding what happens to our immune systems as we age, we can break that link.”
Ageing of the immune system is accelerated by the usual baddies: smoking, a sedentary lifestyle, weight gain and an unhealthy diet. By improving these and other factors, you can turn back the immunity clock.
Dr Jenna Macciochi, a lecturer in immunology at the University of Sussex and the author of Immunity: The Science of Staying Well, says it is possible to have the immune function of a 30-year-old in your sixties or seventies — and vice versa.
“There is now data proving that our immunological age is not the same as our chronological age. We know there is a decline with age, but our immune systems are a bit like cars, and whether you have a Nissan or a Ferrari, it is how well you look after it that makes the difference.”
Daily exercise and immune-strengthening dietary habits are key to anti-ageing our immunity. Lord, 63, acts on her own advice to keep her immune system youthful.
“I run six mornings a week, with one of those runs in high-intensity interval training style,” she says. She also fasts once a week, drinking only water that day.
“With age, the diversity of our gut flora reduces, allowing harmful bacteria to take over,” she says. “An occasional fast reduces inflammation and helps the good bacteria to flourish.”
Here’s what else you can do to lower your immune age.
Walk 10,000 steps a day
Lord and her colleagues looked at the effect of daily physical activity on neutrophil movement, a type of immune function, in a group of older adults (average age 67) for one of their studies. “Neutrophil movement matters because these cells are our main defence against bacteria such as those that cause pneumonia,” Lord says. “They have to be able to move from the blood quickly and efficiently as many bacteria grow very rapidly and so must be found and killed quickly.”
For the trial she compared people who were most active, doing 10,000 steps a day or more, with the least active, who managed 3000 to 5000. “We found that those doing 10,000 daily steps had neutrophils that behaved like those of young adults,” Lord says. “What we can say is that 3000 to 5000 steps a day is not enough to have an effect on immune function as we age and 10,000 daily steps is enough to elicit changes.”
Try HIIT three times a week
Lord is a fan of high-intensity interval training, not least because her findings suggest it can successfully slow the ageing of our immune function. She asked 27 sedentary middle-aged people to take part in a short, sharp HIIT class on bikes three times a week. Each HIIT session comprised a five-minute warm-up of low-intensity cycling followed by high-intensity sprints of between 15 and 60 seconds, interspersed with periods of “active rest” (45 to 120 seconds) when the participants pedalled lightly.
The HIIT class produced favourable changes in immune function, specifically antimicrobial and bacterial functions of infection-fighting neutrophils and monocytes, that matched the immune gains from a moderate-intensity continuous workout (a five-minute warm-up of low-intensity cycling followed by 30 to 45 minutes of moderate pedalling).
Another trial on 12 older adults with rheumatoid arthritis showed that a HIIT walking session three times a week (involving a five-minute warm-up and cool-down and a 20-minute workout with 10 60-second intervals at an intensity that left them puffing hard) produced similar benefits. “We also found our volunteers enjoy this form of exercise as it didn’t take long to do,” she says.
Fast once or twice a week
There are few studies to support the idea that intermittent fasting — such as the 5:2 approach — benefits immunity in ageing adults, but that’s not to say it doesn’t work. “Fasting places the body under mild stress and, as a consequence, it kills off tired old immune cells when you fast and kick-starts the production of new ones once you resume eating,” Macciochi says.
Lord says that a twice-weekly fast “does appear to have beneficial effects on the gut microbiome, with one study in humans showing that fasting twice a week encouraged the growth of health-promoting bacteria” that will help to fight off infection.
Get on your bike
Staying active throughout your adult life can have a marked impact on immune function. The thymus organ, situated between the lungs behind the breastbone, makes T cells, which help the immune system to respond to new infections. From age 20 the thymus tends to start shrinking, producing fewer of these disease-fighting cells.
However, in a study on 125 men and women cyclists aged 55 to 79, Lord found that thymuses of the committed cyclists — men able to ride 100km in under six and a half hours and women to cycle 60km in five and a half hours — were making as many T cells as younger people. “The exercisers had high levels of a hormone called interleukin 7 (IL-7), a critical growth factor for T cells and helps to stop the thymus from shrinking,” Lord says.
Would there be a positive effect if cycling were taken up at any age? “We don’t know for certain, but my guess is yes,” Lord says. “Studies in mice have shown that if you give them IL-7, the thymus can be restored, and we think that active muscles will make more of this hormone and keep the immune system, and especially the thymus, young.”
Take a vitamin D supplement
“Vitamin D is critical for the immune system,” Macciochi says. “It’s a steroid hormone and our immune cells have receptors for it on their surfaces, plus it helps some immune cells function much better.” Take it daily.
Eat 30g of fibre a day
Our body’s biggest microbial load sits in the gut. “It is connected to and influences everything,” Macciochi says. “It really is true that 70 per cent of our entire immune system resides in the gut.” A diverse, high-fibre diet is now considered paramount. “When your gut microbes chow down on fibre, they produce by-products known as ‘postbiotics’. These by-products act as an interface between diet and immunity, changing the personalities of our cells, and circulate in the blood to affect the whole body regulation of our immune system.”
The postbiotics from dietary fibre help to fight infection by tuning up virus-fighting cells, studies have shown. Yet most of us consume too little of it. So increase your intake of fruit, vegetables, wholegrains, nuts, seeds and pulses to make the mark.
Maintain good oral hygiene
Since the mouth is the entry to your gut, oral health is vital to immunity. “Every time you swallow you ingest thousands of bacteria — some bad, but, most importantly, some good,” Macciochi says. “And your oral microbiome speaks with your immune system, just like the bugs in your gut.”
Thorough brushing and flossing daily are essential, although “some mouthwashes tend to eliminate beneficial bacteria in the mouth”, Macciochi says. “Mouthwash containing chlorhexidine has the potential to disrupt levels of good bacteria.”
Do push-ups and lift weights
Resistance work using weights or exercises such as lunges, push-ups and squats is vital. Lord says: “When muscle is moving it can improve the immune system, for example by producing hormones called myokines such as IL-6 that help immune cells to function and keep inflammation down.” Increased inflammation with age is one of the factors that increases the risk of age-related conditions such as heart disease. “Strength work is an absolute essential as we get older,” Macciochi says. “It really can rejuvenate your immune age.”
The Times
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