Four habits to boost your immune system and increase your lifespan, according to a scientist

Telegraph

2 days ago

We know what our immune system is about. It's what fends off bugs and determines how long it takes us to recover from illnesses. We may have attempted to boost it by popping a multivitamin, eating an orange or even trying an overpriced ginger shot when we feel a cold brewing.
But this narrow view barely scratches the surface of its wide-ranging impact not only on our health but also our longevity, says immunologist Dr Jenna Macciochi. 'Our immune system is the single greatest arbiter of both how long we live and the quality of those years,' she writes in her new book Immune to Age: The Game-Changing Science of Lifetime Health.
At a time when longevity has become the latest obsession of millionaire tech bros (Bryan Johnson spends up to $2 million a year to extend his life expectancy through hit 40-a-day supplement habit, morning oxygen therapy and regular plasma transfusions from his teenage son), Dr Macciochi's focus is on improving the simple things – mainly our diet and exercise levels – to harness the power of our immune system to keep us in better health for the 80 years we're likely to live for.
'The longevity space has become dominated by male voices, 'hack your way to the perfect protocol', '20 things to do before you leave your house in the morning',' she says. 'I wanted to be the anti-Bryan Johnson.' There's no evidence that living this way will extend your lifespan or make your latter years any healthier, Dr Macciochi notes.
And she would know – she's a bona fide scientist. After growing up on a farm in rural Scotland, which kickstarted her fascination with health and disease, she studied immunology at the University of Glasgow before securing her PhD at Imperial College London. She went on to work for biotech companies and research institutes before lecturing at the University of Sussex. She is now a consultant and author based in Brighton, where she lives with her two children.
What is our immune system?
'Most people will be able to tell you where their digestive system is, where the brain is, where their lungs are,' Dr Macciochi notes.
The immune system, meanwhile, is a harder concept to grasp. It's made up of hundreds of different types of cells and signalling molecules, controlled by around 8,000 genes – making it the second-most complicated system in our body, after our brains.
Rather than being in one place, it's located throughout our bodies. Around 70 per cent of the immune system is found in our digestive tract while the rest ranges from the skin's surface to our bone marrow, as well as from brain to big toe. 'It's a testament to how important it is,' she says.
How has it been misunderstood?
'I'm trying to get people to stop just thinking about their immune system for colds and flus,' Dr Macciochi says. Protecting us from bugs is one of its key roles, however. It's why immune cells line the entry points to our bodies – the eyes, nose and mouth – which are coated in a defensive mucus that aims to catch viruses and bacteria before they can travel deeper into our bodies.
'We've always looked at the immune system through the lens of infection, which became less relevant in a country like the UK in the last 50 years because we have antibiotics, we have vaccines and we have public health measures that means we're not dying from antibiotics, diphtheria and measles,' Dr Macciochi notes.
However, our immune system is also working in other ways to keep us well, Dr Macciochi notes. It monitors and eliminates potential cancer cells, protects against autoimmune disorders and manages our response to allergens.
It even plays a role in chronic diseases, as inflammation, which is triggered by the immune system, is thought to be a driving force in heart disease, diabetes, cancer and dementia, she notes.
How is our immune system linked with longevity?
The immune system is what has kept the human species alive for hundreds of thousands of years by triggering an inflammatory response when we become infected with a virus or bacteria. 'It makes the body a hostile environment for a germ, so you can kill the germ and get rid of it,' Dr Macciochi explains.
However, this inflammatory response is being triggered too often as a result of our modern lifestyles that typically consists of a poor quality diet, frequent exposure to pollutants and mental stress, she says.
'It's sending danger signals to our immune system but the danger isn't a real danger and it's not acute, it's like constant, tiny hits,' Dr Macciochi says. The result is 'inflammageing' which is the low-level, unwanted inflammation that builds up over time. 'It's like rust on a car' and fuels the onset of non-communicable diseases.
'Inflammation will happen anyway – there'll be a gradual increase with age, just like everything wears out with time,' she notes. 'I don't think we can make ourselves invincible to that but we can definitely push back on this slow burn of chronic inflammation.'
Research into the hallmarks of ageing has shown that inflammation accelerates them all, Dr Macciochi says. 'The telomeres on the end of our chromosomes, which are protective tips, inflammation accelerates wearing that down. The mitochondria in our cells, which are these little energy battery packs, the inflammation makes them less efficient.' It also contributes to DNA damage, which can drive the growth of cancer, she says.
'In all of these systems, inflammation puts this extra burden on top of them, so they have to work harder and then over time you get the wear and tear effect.'
Four habits to boost your immune system and increase your lifespan
'In the UK, we live on average to 80, which is amazing, compared to 150 years ago when you'd be lucky to get to 50,' Dr Macciochi says. 'We've had an amazing longevity revolution already.'
However, the average Brit has a health span of 60, meaning there are '20 years where, medically, we can keep you alive and functioning but your quality of life might not be very good', she says. 'You might be on multiple medications and then medications to treat the side effects of those medications.'
While our body's system will decline with age, unhealthy lifestyles preclude us from engaging in the activities that keep us young, she says. Setting up good habits that support our immune system now can elongate the number of years we spend free from illness – these are the habits Dr Macciochi recommends.
Do more exercise
It's not news that exercise is good for us but its ability to improve immune health and life expectancy really are second to none, according to Dr Macciochi.
One study found that regular exercisers live up to seven years longer but also have more years in good health. 'There are very few, if any, things medicine can offer that come anywhere close to that magnitude of benefit,' she notes.
Surprisingly, the benefits of exercise stems from the fact that it triggers inflammation – but the good kind. 'I liken it to a dirty kitchen table,' Dr Macciochi says. 'If I spill some coffee on it, and then I clean it, I'm going to end up with a table that's cleaner than it was before I spilled the coffee. That's how exercise works as an anti-inflammatory.'
'You exercise and get a rise in inflammation, but in a very controlled way that then gives this super rise in anti-inflammatory kind of clean-up, which doesn't just clean up the muscles that you've been working in the gym but works across the whole body,' she says. 'It's one of the best anti-inflammatory tools we have.'
Exercise also keeps the thymus gland healthier for longer. This is located in our necks and produces T cells, which are the master controllers of the immune system, but its performance declines with age and it has deteriorated significantly by the age of 70, which is why older adults become more vulnerable to infections like pneumonia and shingles, Dr Macciochi says.
'There's some lovely research showing that physical activity offsets that decline,' she says. 'It's not going to stop it, it will still have this change but it's going to be happening much slower.'
Ideally, we should all be doing some cardiovascular exercise and resistance-based exercise, Dr Macciochi says but most people will benefit simply from breaking up long periods of sitting, she says.
'Don't defer until the perfect week when you can get to the gym five times,' she says. 'Take your baseline activity level and make an increment, make it sustainable and then build it up again.'
Eat fewer calories and stop snacking
'As a nation, we are eating almost all the time,' Dr Macciochi says. Research shows that people are in a 'fed state' for 18 hours a day. 'Our digestion was never designed to cope with this,' she says. In the time after eating a meal, our bodies need a break to digest the food and return postprandial (post-eating) inflammation to baseline levels, she explains.
'If you're snacking from 7am to 9pm, your body is never getting that nice rhythm,' Dr Macciochi says. Unwanted inflammation will build up and contribute to inflammageing, she says.
Meanwhile, studies have shown that eating less – reducing calories by 20 to 30 per cent while still meeting all nutritional needs – reduces inflammatory markers and inflammageing, she notes. While this approach may be recommended for younger people, especially below the age of 40, Dr Macciochi advises older groups against calorie restriction, so that they don't lose muscle mass.
However, people should focus on consolidating their food into three meals, she says. 'Make those meals really nourishing to prevent grazing all the time because we know that's really not helpful for inflammation.'
Add anti-inflammatory foods to your meals
Olive oil is one of the most-researched anti-inflammatory food, Dr Macciochi says. 'It contains oleocanthal which has a molecular structure similar to the well-known anti-inflammatory ibuprofen,' she notes.
'It's thought that people in the Mediterranean are living so long and so well because they're getting this tiny anti-inflammatory effect every day through the olive oil that they use,' Dr Macciochi says. 'If people want to invest in a longevity supplement, I would say start with olive oil.'
The wider Mediterranean diet is made up of minimally processed grains, legumes, nuts, seeds, fresh seasonal produce, olive oil and oily fish, she notes. 'These dietary patterns don't just prevent chronic disease – they actively mitigate the mechanisms driving inflammageing,' according to Dr Macciochi.
Research also shows that adopting the MIND diet, made up of antioxidant-rich leafy greens, berries, wholegrain, nuts beans and fish, will reduce inflammation and protect against Alzheimer's. 'It has been designed to take elements that are good for brain health,' Dr Macciochi explains. 'It's high in polyphenols, antioxidants and it's good for the gut and it's anti-inflammatory.'
'People don't make the link between cognitive function and inflammation but that's a growing area,' she says. 'If we have raised inflammation in the body, that will be affecting what happens in the brain. We have immune cells in the brain called microglia and when they sense danger, they start spitting out inflammation which we know is then linked to cognitive decline.'
Eat more fibre to improve gut health
'Around 70 per cent of our immune cells are located along the digestive tract,' Dr Macciochi notes. 'The main reason for that is because the digestive tract is an obvious route for infection. We also have a collection of microbes that live in there and make up the microbiome.'
Our microbiome is essential for producing immune-modulating cells, such as T cells which prevent the immune system from overreacting to harmless substances or underperforming when we do encounter a bug, she explains.
Fibre is the forgotten key for good gut health and good immune health. 'When your microbes break it down, they produce short-chain fatty acids which are anti-inflammatory,' Dr Macciochi says. 'They keep the gut barrier really tight. They help seal up postprandial gut leakiness.
Vegetables, fruit and legumes are all rich sources of fibre but it's important to increase how many you're eating slowly to reduce the risk of uncomfortable bloating, she adds.
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