Will following tips of 'longevity gurus' keep you healthy to 100?

Bryan Johnson says he has no plans to get older or die. Impossible? Obviously, yes. But the 46-year-old Californian tech billionaire is giving it a good go.

He follows a strict regime of 100 vitamins a day, a daily 23-hour fast (that's right, he eats only during a one-hour window) and, until recently, blood transfusions from his son.

Johnson claims the process has 'reversed' his age. A team of doctors scan his body every week, and they say he has the heart health of a 37-year-old, the skin quality of a 28-year-old and the fitness level of an 18-year-old.

And he is far from alone. There are a growing number of self-appointed experts using social media to promote their own guides to living – if not for ever, then for several healthy decades more than the average person.

These longevity influencers argue that by following strict – and often unconventional – lifestyle regimes, we can 'hack' – or beat – the ageing process and dramatically reduce the risk of developing the diseases of older age, such as cancer, diabetes, heart disease and dementia.

Bryan Johnson says he has no plans to get older or die. Impossible? Obviously, yes. But the 46-year-old Californian tech billionaire is giving it a good go

And they are staggeringly popular. One of the most successful, 50-year-old Canadian Dr Peter Attia – a former cancer doctor – has more than 1.5 million followers on YouTube and Instagram, and is author of a number one bestselling book, Outlive: The Science And Art Of Longevity.

Is a sauna or ice bath better for your body?  

Many longevity gurus urge followers to take regular ice baths and use saunas to help them live longer.

According to Dr Tamsin Lewis, founder of UK longevity health firm Wellgevity, they can reduce the risk of cardiovascular and neurodegenerative diseases.

Cold temperatures, she says, reduce inflammation by narrowing blood vessels, limiting blood flow to injured areas.

Many longevity gurus urge followers to take regular ice baths and use saunas to help them live longer. Above: Actor Chris Hemsworth and Dr Peter Attia in a sauna

'Whatever doesn't kill you makes you stronger,' says Dr Lewis, a former GB triathlete with about 20,000 followers on Instagram. 'Exposing your body to hot and cold is similar to exercise. It makes you more resilient and you age better.'

A 2015 study that followed 2,300 Finnish men over 20 years found those who visited saunas around four to seven times a week were less likely to die of heart attacks and strokes than those who did not. And research suggests that regular saunas have few health risks, even for people with heart conditions.

But ice baths, popular with celebrities such as Harry Styles, are backed with little scientific evidence. A Swiss meta-analysis published last year in Scientific Reports could not find any data to suggest it boosted long-term health or reduced pain.

Deaths have also been linked to cold-water immersion. Last year a coroner's inquest found that a 39-year-old woman died due to a cold water experience in the River Goyt in Derbyshire, which caused her heart to stop.

'Saunas are good for the body, especially your cardiovascular health,' says Professor Jose Gonzalez-Alonso, an exercise expert at Brunel University London. 'But the same evidence doesn't exist for ice baths, which can be dangerous.'

Dr Attia, who reportedly charges his private patients £120,000 a year, suggests that going barefoot as often as possible as well as carrying heavy weights in a backpack can help extend health life by decades.

Meanwhile Ben Greenfield bills himself as a 'biohacker, nutritionist, physiologist, fitness coach, athlete and bestselling author of 13 books'. An advocate of ice baths and coffee enemas (see panel on right), the 43-year-old claims tests have shown he has the biological age of a nine-year-old.

These longevity gurus appear in documentaries side-by-side with A-list celebrities (who are their clients, naturally), on the world's top podcasts and their speaking tours sell out in seconds. Given their message – and enviable physiques – it's unsurprising people are transfixed.

'These influencers claim they can keep you healthy for ever,' says Professor Ilaria Bellantuono, an ageing expert at the Healthy Lifespan Institute, University of Sheffield. 'The scientific evidence to support their claims is often shaky, but people are getting caught up in this promise of long-lasting youth.'

So is their advice worth following? We have assembled some of Britain's top ageing experts to dissect their most eye-catching claims, so read on to find out...

CAN EATING VERY LITTLE DE-AGE YOUR CELLS?

Many longevity gurus promote fasting – from missing meals to entire days with no food. It sounds like no fun at all but it's claimed that fasting is able to reduce the number of senescent cells in the body.

Dubbed 'zombie cells', these are cells that are still alive but not functional. If they build up, they can weaken our tissues, organs and the immune system, leading to the diseases of ageing. But Bryan Johnson takes the concept to extremes.

The billionaire, who has more than 540,000 followers on Instagram and was interviewed by the MoS last June, eats just once a day, at 8.30am. The meal usually includes raw vegetables, a sweet potato salad, nuts and fruit. He recently published the full menu, including precise amounts of each ingredient.

Johnson says it provides him with 2,250 calories and he now 'experiences exquisite pleasure tasting, smelling and consuming'. But Johnson may be eating fewer calories than he thinks, says Dr Duane Mellor, a dietician at Aston Medical School: 'There can't be more than 1,600 calories in this diet. I do not advise anyone to follow it.'

Setting this aside, experts say there is evidence that some fasting can be beneficial and does remove zombie cells. In trials, rodents given a time-restricted diet – fasting for 12 hours a day – displayed improved fitness, kidney function and a longer lifespan than those allowed to eat regular meals.

Ben Greenfield bills himself as a 'biohacker, nutritionist, physiologist, fitness coach, athlete and bestselling author of 13 books'

Dr Tamsin Lewis, who runs healthcare company Wellgevity, says that breath work helped her recovery from a severe case of long Covid

However, experts say that the extreme fasting carried out by Johnson is unnecessary.

'Growing evidence suggests that intermittent fasting for 12 hours helps clear out some of the rubbish in the body,' says Prof Bellantuono. 'This is achievable as that just means not eating late at night – the bulk of the fast can be while we are asleep.

Are coffee enemas a cure for cancer? 

It may sound unlikely – and uncomfortable – but influencer Ben Greenfield claims that regular coffee enemas are a way to keep the body in top physical condition.

'Coffee enemas can clean and heal the colon, detoxify the liver, reduce many types of chronic pain and increase mental clarity and energy levels,' he writes on his blog.

An enema is a medical procedure in which fluid is pumped into the rectum – typically used to alleviate constipation. It is usually done using water, but this version involves lukewarm coffee.

It may sound unlikely – and uncomfortable – but influencer Ben Greenfield claims that regular coffee enemas are a way to keep the body in top physical condition

The practice has long been part of an alternative therapy known as the Gerson method, which involves a strict low-salt, organic fruit and vegetable diet alongside up to five coffee enemas a day to prevent cancer. In 2004, King Charles – then Prince – was criticised for backing the method as a cure for cancer.

If you needed any convincing, experts say the practice should be avoided.

A review by The National Cancer Institute in the US in 2010 found no evidence that coffee enemas helped people with cancer.

Meanwhile, enemas administered incorrectly can have dangerous complications.

Professor Edzard Ernst, a leading expert in alternative medicines, formerly of Exeter University, says: 'The main risk of an enema is a perforation of the colon which can be fatal.'

'Fasting for longer periods is not realistic for a lot of people as it can be unpleasant and may lead to eventually over-eating due to extreme hunger. It's much more important to build healthy, sustainable eating habits you can stick to.'

PUMP SOME IRON TO INCREASE RESILIENCE 

If you want a long, healthy life and envisage yourself 'playing with your great-grandkids someday', then weight lifting to build up muscle mass 'should be a priority,' according to longevity expert Dr Attia. He recommends that people of all ages regularly do resistance exercises, including deadlifts and squats, and argues that building up the body's big muscles can make it more resilient, reducing the risk of life-threatening injuries later in life. 'Muscle strength is so important because, as you get older, frailty becomes a liability,' he says. 'A fall can be catastrophic at the age of 65.'

The experts we spoke to agree that strength is a crucial attribute for a long and healthy life. Studies suggest people who perform strength-based exercises are less likely to die prematurely than those who don't, regardless of whether they do aerobic exercises such as running.

This is largely due to the fact that muscle weakness and frailty are strong indicators of an early death. Research suggests that the weakest 15 per cent of the population are three times as likely to die within a year than the top 15 per cent. But there is disagreement over how much strength training is beneficial.

Dr Attia said recently: 'If I wanted to be the fittest version of me in my 80s, I'd work out for one-and-a-half to two hours a day.'

But in 2021, one of the most authoritative studies into the benefits of strength training was published in the British Journal of Sports Medicine, involving 416,000 Americans. It found that 30 minutes to a full hour of weekly strength training, such as lifting dumbbells, combined with three hours of aerobic exercise, was most beneficial for long-term health. It concluded that more than a hour did nothing to extend life, while significantly more may even increase the risk of health problems.

DITCH YOUR SHOES AND GO BAREFOOT

Supportive shoes may be comfy, but influencer Dr Attia says they are 'damaging' because they weaken the muscles in the legs and feet.

'Shoes shield us from what our feet should be doing,' he claims. 'Most people need to learn to strengthen the intrinsic muscles of the foot.'

Dr Attia tells his followers go shoeless as often as possible or wear 'barefoot' shoes.

He argues that this improves stability and reduces the risk of long-lasting injuries which can impact healthy living.

'For most people with some sort of chronic injury, it can be traced back to an instability,' he says. 'Whether that's an instability of the lower back which leads to back pain or instability in the feet to knee pain.'

Supportive shoes may be comfy, but influencer Dr Attia says they are 'damaging' because they weaken the muscles in the legs and feet

Barefoot shoes have no supportive sole – usually just a thin, tough piece of grippy rubber – so wearers put equal weight on all parts on their feet while moving.

A significant number of scientific studies have shown that they increase stability and muscle strength, including a 2020 University of Liverpool study which found that the minimal shoes boosted the joint health of older people. Leading brands include Vivobarefoot and Xero.

But experts warn that the long-term effects are still unknown.

'Barefoot shoes are still relatively new, so we don't know what impact they'll have on feet over a long period,' says Dr Stewart Morrison, a physiotherapy expert at King's College London.

'If you switch to a barefoot shoe, the sudden change in walking style could lead to an injury in the foot or leg.

'Anyone considering this change should wear them for short periods to get used to the experience.'

100 VITAMINS A DAY TO KEEP THE DOCTOR AWAY

Vitamin supplements are not revolutionary, but some influencers promote the consumption of a huge number. Bryan Johnson says he takes 104 vitamins a day in supplement form to complement his diet.

These include common supplements Vitamin D, magnesium and zinc. But he also takes rarer pills including ashwagandha, genistein, taurine and zeaxanthin.

Dr Peter Attia – a former cancer doctor – has more than 1.5 million followers on YouTube and Instagram, and is author of a number one bestselling book, Outlive: The Science And Art Of Longevity

The billionaire says the number is determined by a team of doctors who regularly run tests to see which nutrients he is lacking.

It's certainly true that many people in the UK do not get enough vitamins. One in five Britons have a Vitamin D deficiency, which increases their risk of bone problems and may impact the body's ability to fight infection.

However, experts say eating the right food – and for Vitamin D, getting sunlight – is preferable to taking supplements. This is because there is still debate over what percentage of the vitamins in supplements are absorbed and excreted.

Canadian research from 2018 which analysed dozens of studies found that regularly taking vitamins such as Vitamin D and calcium does not reduce the risk of cardiovascular disease or premature death.

'Food is always preferable to pills,' says Dr Elaine Douglas, an ageing expert at University of Stirling. 'It contains more nutrients, such as fibre, which the body needs.'

It should also be noted that Bryan Johnson sells a range of vitamins, with a month's supply costing £40.

HOW SLOW BREATHING CAN BEAT HEART DISEASE 

Controlled breathing – also known as 'breath work' – has become a popular practice, which longevity gurus say can reduce stress and lower the risk of illness.

Dr Tamsin Lewis, who runs healthcare company Wellgevity, says that breath work helped her recovery from a severe case of long Covid. 'Breath work improves anxiety levels and boosts your health,' she says.

Phone apps can help guide people through a number of breathing exercises. One includes the '4-7-8' technique, which involves breathing in for four seconds, holding it for seven seconds, and exhaling for eight seconds.

And there might be something in it. Stress triggers the body to produce hormones such as adrenaline, which in turn raises blood pressure. But a Malaysian analysis of more than 300 studies last year found that patients who regularly practised controlled breathing saw their blood pressure reduced as their stress levels lowered. Similar results have been found for meditation. This is significant because high blood pressure is linked with a number of life-threatening conditions, such as heart disease.

'Lowering stress levels can be done through activities including meditation but also by addressing stressful life factors like work,' says Dr Douglas.

HORMONE THERAPIES FOR BOTH MEN AND WOMEN 

Anyone concerned about ageing should consider hormone replacement therapy (HRT) according to Dr Attia – and that includes men. He says both sexes can improve their quality of life by taking these drugs at the appropriate time.

For women, this means taking oestrogen, progesterone and possibly testosterone within ten years of the menopause. Men should consider testosterone replacement therapy (TRT) if they have been diagnosed with low levels.

'The data for responsible use of TRT is very positive,' Dr Attia said on the The Diary Of A CEO podcast. He added that he believed it was a relatively low-risk drug to take with 'many benefits' such as reducing fat and increasing muscle.

Anyone concerned about ageing should consider hormone replacement therapy (HRT) according to Dr Attia – and that includes men. He says both sexes can improve their quality of life by taking these drugs at the appropriate time

Meanwhile he said that HRT was a 'net positive', reducing menopause symptoms while protecting bone health.

Experts say there are many benefits to HRT, but it is not a panacea.

Multiple studies show that it reduces symptoms of menopause but NHS guidance does not recommend it for those just wanting to boost their health.

This is due to the risk of side effects, which include a slight increase in breast cancer.

Men diagnosed with significantly low testosterone are also offered TRT if they experience symptoms such as depression, loss of sex drive and erectile dysfunction.

'HRT is not an elixir of life, it's not going to reverse ageing,' says Professor Joyce Harper, a reproductive expert at University College London. 'This idea that we all have to medicate constantly is a worrying phenomenon.'

IS VEGETABLE OIL TO BLAME FOR CHRONIC DISEASE?  

Anyone who wants to avoid chronic disease must 'ruthlessly eliminate' vegetable oils from their diet, according to longevity influencer Ben Greenfield.

'Vegetable oils are leading drivers of chronic disease, negatively impacting your metabolism, levels of inflammation, weight and cancer risk', he argues on his blog.

He believes that, in the past century, the increased use of vegetable oil at the expense of other fats such as butter has led to an increase in heart disease and obesity.

There are particular concerns over omega-6, a fatty acid found in many vegetable oils, which some scientists have argued can increase inflammation in the body.

However, experts say this theory has been widely debunked. According to the American Heart Association, dozens of studies show that omega-6 does not increase the risk of cardiovascular disease. 'Vegetable oils are often used to cook unhealthy products, but that doesn't mean the oil itself is causing harm,' says Dr Mellor.

USING RED LIGHT TO GROW HAIR AND HEAL INJURIES  

Specific types of light can de-age the skin and regrow hair, according to some influencers.

Bryan Johnson, who began losing his hair in his 30s, wears a cap which emits red light – close to infrared – for six minutes a day to combat hair loss. He also uses a portable red light-emitting device to combat aches and pains.

'There's good evidence that red light can accelerate healing,' he says. 'If I'm ever feeling some slight injury from playing sport or exercise, I put it on that area.'

Johnson also stands in front of a UV light for five minutes in the morning, which he says improves his 'mood, sleep and energy'.

But there is little evidence to support the claims. While some laboratory studies show that red light can improve blood flow, there are no high-quality human trials which prove it can reverse hair loss or combat skin problems.

'It sounds cool but there's little evidence to support it,' says Dr Hiva Fassihi, a dermatologist at King's College London.

She also doubts there is much benefit to a UV light. 'I'd recommend they just go outside and get it from the sun,' she adds.