London Marathon: How to run in the heat

This year’s London Marathon is likely to be the hottest yet, so how do you run a marathon in the heat?

On Sunday some 40,000 people are expected to take part in the race in temperatures that are forecast to reach up to 23C (73F), which would break the previous record of 22.2C (72F) in 1996 and 2007.

Organisers have contingency plans in place, including more water at drinks stations, more showers, and extra ice at first aid stations.

But Greg Whyte, professor of sports science at Liverpool John Moores University, says he nevertheless expects “carnage” in terms of the number of people who become ill during the race.

That is because not only is it due to be hot, but temperatures have risen very quickly, so runners will not have had time to adapt.

“Most of the runners will be completely un-acclimatised to the heat, so they’re not in a good position to cope with it; it’s very difficult to combat that,” says Prof Whyte.

That means it is very important for runners to adapt their strategy for the race.

  • London Marathon could be hottest ever
  • Marathon sees record numbers take part

    Reduce your pace

    Many marathon runners will have a time they hope to beat when they complete the 26.2 miles on Sunday.

    But experts say one of the most important measures people can take when running in the heat is to put such targets aside and make sure they run a slower marathon, starting from the beginning of the race.

    It is those who rigidly stick to their pre-race plans who will be at the greatest risk of harm.

    “They’ve set their target for their race, particularly in terms of time, and they’ll shoot for that time irrespective of what else is going on,” says Prof Whyte.

    “And that’s where the mistakes will be made.

    “What you’ll see with the elites is you’ll know they’ve adapted their race strategy because there won’t be records broken if it’s really hot,” he adds.

    People can monitor their pace with a watch or even use wearable technology to check their heart rate and try to match it to levels reached during their longest runs in training.

    Stay hydrated

    In hot marathons, runners can lose up to four litres (seven pints) of fluid through sweating and exhalation, putting them at risk of dehydration, which is why it is important to drink enough water.

    Prof Whyte says it is important to do this “little, often and early” and not wait to become dehydrated.

    Dr Francois-Xavier Li, a lecturer in sports sciences at Birmingham University, says it is important to also consume carbohydrates with these liquids because they help your body to hydrate better.

    This can be done with sports drinks or by having small amounts of food with drinks, including energy gels.

    Some experts warn against taking on too much liquid, because in extreme cases it can lead to water intoxication, a potentially fatal condition.

    Prof Whyte said this was “very uncommon” and people were far more likely to end up dehydrated.

    Dousing your head and the back of the neck with water or by using the showers also helps to reduce body temperature.

    But it is important not to get too wet as this raises the risk of parts of the body becoming blistered or chafed, particularly the feet.

    Be prepared in advance

    While experts say pacing and hydration are the most important factors for running a marathon in the heat, there are other important preparations.

    Sun cream is important to help protect the skin from burning and becoming too hot, but it is important to get a cream that is water-resistant so that it does not drip into your eyes.

    Clothing can also make a difference, with light-coloured and loose-fitting clothes recommended, along with a hat for protecting runners from the sun – as long as the hat is not made from thick material.

    But what if you are one of those who are planning to run in a costume?

    The London Marathon organisers have warned people to “think carefully whether that is still appropriate in the conditions”.

    But Prof Whyte thinks it would be wrong to discourage people from wearing such outfits – often for charity – and says these people just need to be extra careful to make the necessary adjustments.

    Listen to your body

    While steps can be taken to prevent harm, what should you do if you end up reaching “the wall” – that point where it feels too hard to carry on?

    If you find yourself feeling tired, you should slow your pace or even walk, experts say.

    But what are the signs that you might actually be in danger of becoming ill?

    Headaches, confusion, loss of muscular control, feeling cold or no longer sweating could be signs that you are in fact sick.

    If you feel any of these symptoms, you should slow down and make sure to drink.

    And if this does not make you feel better you should ask for help at one of the first aid stations, rather than wait by the side of the road where it may take longer for you to receive attention.

    So overall, how should you approach a marathon in the heat?

    Above all else, you should should try to have fun rather than focus on race goals.

    “The vast majority of runners, they’re not getting paid to do this, they’re not going to get any prize money, they’re not going to earn their fame and fortune out of the time they run,” says Prof Whyte.

    “What they should be doing is enjoying it, and really judging how they are responding as to whether they’re enjoying it or not, and try to bring it down to that very basic level constantly.

    “If you are a first timer, make sure you’ve always got a smile on your face,” he adds.

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Can we trust BMI to measure obesity?

You’ve been using our fat calculator in your droves, working out your BMI (body mass index) and comparing the result with people in your age group and your part of the UK.

But a few people have been critical. They say using BMI to measure whether they are healthy, overweight or obese is misleading.

So what’s the truth? Can we trust what it tells us?

Is BMI the best measure of obesity?

Firstly, it is a quick and easy way of working out whether you are in the healthy category by using two simple measures – weight and height.

Most doctors say it is the best method they have, it’s pretty accurate, can be measured simply in clinic and is acceptable to patients.

If you can’t see the calculator tap or click here.

But does it work for everyone?

No, not all.

And this provoked a few comments along these lines: “Why, in this day and age, are you using BMI to tell people they are overweight? It is an outdated method that does not take into consideration muscle and actual health! I am extremely fit and healthy with a low body fat percentage, yet your BMI tells me (and many more self-conscious girls) that I am overweight!”

There are some people who carry a lot of muscle and little fat, like bodybuilders, boxers and rugby players.

Muscle is much denser than fat so they may end up with a BMI that classes them as obese, despite the fact they may be fit and healthy.

But this is thought to apply to fewer than 1% of the population. Most people aren’t extreme athletes.

Tim Cole, professor of medical statistics, at University College London Great Ormond Street Institute of Child Health, said BMI was “still extremely relevant”.

“You don’t see many bodybuilders around but you do see lots of people with large waists. Many people get exercised about that wrongly.”

As people age, they lose muscle and may be classed in the “healthy weight” range even though they may be carrying excess fat. This is particularly true of smokers.

BMI also doesn’t apply to pregnant women, and some ethnic groups have a higher risk of health problems at lower BMI levels.

Does BMI actually measure fat?

It can’t measure how much excess fat we have in our bodies – as opposed to muscle and bone – because that would require some pretty complicated and expensive medical procedures, which just aren’t practical to carry out on the whole population.

What it does do is give a healthy weight range for a particular height, taking into account variations in body shape – and it provides a good starting point for the majority of people.

It also doesn’t measure how fat is distributed throughout the body (some fat is ok; too much in the wrong place is a risk).

Research shows that people who carry a lot of fat around their waists are at higher risk of health problems than those with more fat around their thighs and buttocks.

They are more likely to have fat stored in their abdomen around key organs, which could increase the risk of heart disease, stroke and type 2 diabetes.

So waist size may be a better way to monitor your health than BMI. That’s why our calculator included an option for giving your waist size too.

“If people think they have lots of muscle mass, their waists should be lower for a given BMI – so they can easily check,” says Prof Sattar.

How to measure your waist

  • find the bottom of your ribs and the top of your hips
  • wrap a tape measure around your waist midway between these points
  • breathe out naturally before taking the measurement

    Regardless of your height or BMI, you should try to lose weight if your waist is:

    • men – 94cm (37ins) or more
    • women – 80cm (31.5ins) or more

      Can BMI tell us anything about disease risk?

      On its own, it can’t.

      But doctors use BMI in conjunction with other measures – like blood pressure, cholesterol and family history – to work out an individual’s risk of type 2 diabetes or heart disease, for example.

      Body mass index is not specific to any particular health risk – and that’s its strength, experts say.

      However, a BMI above the healthy range or too much fat around the waist is known to increase the risk of serious health problems, including stroke and certain cancers.

      Are we shaming those who are overweight?

      One person said of the BBC calculator: “Your unscientific method of calculating ‘fatness’ is an unhelpful tool that dehumanises those who are obese or overweight, shaming them into losing weight and threatening their fragile relationship with their bodies.”

      There was no intention of shaming people – merely offering a way of finding out about your own weight because excess fat is the cause of an increased risk of a range of diseases.

      If you think you would like to lose some weight, you should go and see your GP for advice first.

      The best way to lose weight is to make small, realistic changes to your diet and physical activity.

      View comments

Ketamine has ‘fast-acting benefits’ for depression

Ketamine has “shown promise” in the rapid treatment of major depression and suicidal thoughts, a US study says.

Ketamine has a reputation as a party drug but is licensed as an anaesthetic.

The study found use of the drug via a nasal spray led to “significant” improvements in depressive symptoms in the first 24 hours.

The Royal College of Psychiatrists said it was a “significant” study that brought the drug “a step closer to being prescribed on the NHS”.

The report by researchers from Janssen Research and Development, a Johnson and Johnson company, and Yale School of Medicine, is the first study into ketamine as a treatment for depression that has been done by a drug company.

It is being published in the American Journal of Psychiatry.

The trial looked at 68 people at imminent risk of suicide.

All patients were treated with a stay in hospital and anti-depressants.

In addition, half were given ketamine in the form of esketamine (part of the ketamine molecule) in a nasal spray and half were given a placebo.

The study found those using esketamine had a much greater improvement in depression symptoms at all points over the first four weeks of treatment.

However, at 25 days the effects had levelled out.

The study’s authors suggest it could offer an effective rapid treatment for people severely depressed and at imminent risk of suicide and could help in the initial stages of treatment, as most anti-depressants take four to six weeks to become fully effective.

The nasal spray is now undergoing phase three trials before it can be licensed for treatment.

Potential for abuse

There were no reports of esketamine dependence or misuse in the trial but the authors warn that more research is needed on the potential for abuse of ketamine and say these should be looked at during subsequent trials.

Scientists in the UK are also studying ketamine as a treatment for depression taken intravenously.

Dr James Stone, from the Royal College of Psychiatrists, told the BBC the “interesting” US study confirmed the findings from successful studies into intravenous ketamine.

“The main reason for its significance is because this is being developed by a drug company and it’s potentially quite likely that this medication might become available as a treatment available on the NHS for depression.”

‘Severe depression’

He said because it was being given as a nasal spray it was “much easier to administer” than intravenous ketamine and was “potentially quicker to give, so it means more people can be dosed at the same time” and you need less equipment.

Dr Stone said if it did go on to be prescribed on the NHS it would be aimed at people with severe depression as a second or third line of treatment if other drugs haven’t worked and could be used for people instead of electroconvulsive therapy.

Prof Mitul Mehta from King’s College told the BBC it was an “exciting” study.

“All the studies to date have been looking at intravenous use – there are some people who have explored oral ketamine but that doesn’t appear to be as successful as intravenous so intranasal seems to be a really good halfway-house.

“It enters the body relatively quickly – it’s not as fast as going straight into your bloodstream but not as slow as via the stomach and it’s reasonably easy to control how much you give to a person. In that respect this is a really important study.”

But he said far bigger studies are needed to look out for any rare side-effects.

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European women twice as likely to be blonde as men, study says

Women from European descent are twice as likely to be naturally blonde as men, according to new research.

The largest ever genetic study on pigmentation looked at nearly 300,000 people of European descent.

It found 124 new genes that play a major role in determining human hair colour variation.

The report’s authors say they are not sure why there are so many more blonde women than men, calling it an “intriguing mystery”.

The study which is published in Nature Genetics, builds on previous genetic studies that had only identified a dozen or so hair colour genes.

The data was supplied by the UK Biobank, American DNA testing company 23andMe and the International Visible Trait Genetics Consortium and their study partners in the Netherlands, Australia and Italy.

They chose people of European descent because of their variety in hair colours.

They found men were three times as likely as women to have black hair.

Prof Tim Spector, joint lead author, from Kings College London, told the BBC they were not expecting to find so many more blonde women than men.

“It’s a mystery and it’s intriguing because it wasn’t what we were looking for. We thought it was a bias but it wouldn’t go away and it’s found in every sub-group of every population we saw,” he said.

“It’s a curious mystery because it’s a very big effect – to see two and threefold effects both in a whole variety of American populations and European ones was quite amazing.”

The researchers say it opens up a whole new area of research to discover why, but Prof Spector has some theories.

“We thought it might have something to do with the attraction of women for darker skinned men and vice versa – but we don’t think the genes are any different. We think the genes are being expressed differently – so for some reason the blonde genes that may be there at birth are persisting in females and disappearing in males.”

So blonde women are just as likely to give birth to blonde boys as blonde girls, but the boys are not keeping their genetically blonde hair when they grow up.

The changing of the expression of genes – switching them off and on – is known as epigenetics.

Prof Spector said it could be other genes that are affecting the process and there are examples of this in mice studies where chemicals, stress and hormones were found to affect the way some of the pigment genes work.

“But some of it could be for evolutionary reasons because blonde women are more likely to be successful with men and men are more likely to be more successful with women if they’re dark-haired rather than light-haired.

“A lot of this is speculation – but it opens up a whole new area of research to try and work out why genes might be expressed differently in men and women and what the motive is – and whether this is a recent cultural change.”

The discovery of 124 genes connected to hair colour also revealed some links to cancers such as skin, testicular, prostate and ovarian.

Other pigment genes they found affected the chances of having Crohn’s disease and other forms of bowel disease.

The researchers, who include experts at Erasmus MC University Medical Centre in Rotterdam, hope their discoveries will help improve the understanding of these diseases and help develop new drugs to target these genes.

The genes also make it easier and more accurate to predict hair colour from DNA, which could help in forensic science for solving crimes, they add.

Does vaginal seeding boost health?

Should Caesarean-section babies be smeared with a sample of their mother’s vaginal fluids as soon as they are born?

“Vaginal seeding” is not mainstream medicine, but it is growing in popularity.

The idea is to give these newborns something they missed when they emerged into the world – the good bacteria that live in their mother’s vagina.

A swab is taken of mum’s vaginal fluid, which is then rubbed on to her child’s skin and mouth.

The hope is this microbial gift will boost their child’s long-term health – particularly by reducing their risk of immune disorders.

It is a crucial time.

We might have been sterile in the womb, but in our first few moments of life an invisible bond is being established between baby and bacteria.

It’s a relationship that will last a lifetime, and the first contact is as important as a first date.

“The first time a baby’s own immune system has to respond are to those first few bacteria,” says Prof Peter Brocklehurst, from the University of Birmingham.

“That we believe is important for, in some way, setting the baby’s immune system.”

There is a noticeable difference between the microbiomes – the collection of bacteria, viruses, fungi and archaea – of babies born vaginally and by Caesarean section.

It lasts for about the first year of life.

A baby born vaginally is first exposed and colonised by microbes from their mother’s vagina and gut.

But for Caesarean-section babies, the first exposure “if they’re lucky”, says Prof Brocklehurst, comes from the very different organisms on their mother’s skin.

He is running the Baby Biome Study to see if these different microbial colonists on Caesarean-section babies explain why they have higher rates of diseases such as asthma and allergies later in life.

The microbiome

  • You’re more microbe than human – if you count all the cells in your body, only 43% are human
  • The rest is our microbiome and includes bacteria, viruses, fungi and single-celled archaea
  • The human genome – the full set of genetic instructions for a human being – is made up of 20,000 instructions called genes
  • But add all the genes in our microbiome together and the figure comes out at between two million and 20 million microbial genes
  • It’s known as the second genome and is linked to diseases including allergy, obesity, inflammatory bowel disease, Parkinson’s, whether cancer drugs work and even depression and autism

    More than half your body is not human

    Gut Instinct: Why I put my poo in the post

    The early interaction between the immune system and microbes appears crucial.

    Obviously our bodies do attack the dangerous ones – but the overall relationship between microbial and immune cells is about more than conflict, it’s a far deeper dynamic.

    Graham Rook, a professor of medical microbiology at University College London, says the microbiome is the immune system’s teacher.

    “This is a learning system, it is like the brain. Now, the thing about the adaptive immune system is it needs data, just like the brain needs data.”

    Listen to The Second Genome on BBC Radio 4.

    The next episode airs 11:00 BST Tuesday April 17, repeated 21:00 BST Monday April 23 and on the BBC iPlayer

    And that “data” is coming from microbes and the chemicals they produce. They provoke a reaction in the immune system that can last a lifetime.

    Prof Rook says: “The initial setting up of the immune system occurs during the first weeks and months of life.

    “We know that because there’s a window of opportunity during those first months of life when if you give antibiotics you can disrupt the microbiota and then in adulthood those individuals are more likely to have immunological problems and are more likely to put on weight.”

    This is the idea that some parents are buying into when they perform vaginal seeding.

    Do dogs boost a baby’s microbiome?

    Even the type of home you bring your baby back to may affect their long-term health.

    Research has shown households with dogs have lower rates of asthma.

    The idea is they help us swim against the hygiene tide by traipsing their muddy paws round the house and sticking their noses into everything.

    “The speculation has always been that the dog brings, from the outside, microbes that are helpful in stimulating the infant’s immune system,” says Prof Anita Kozyrskyj, from the University of Alberta.

    She is analysing data on about 3,500 families in the Canadian Healthy Infant Longitudinal Development Study.

    One of its findings is that the microbiomes of three-month-olds is far richer and more diverse (a good sign) if there is a pet in the house.

    Two types of beneficial bacteria seemed to be more common.

    “The Oscillospira have been associated with leanness and the Ruminococcus have been associated with reduced risk of allergic disease.”

    Breastfeeding or formula, antibiotics and method of delivery all affect the microbiome.

    But studies into the microbiome and long-term health have often been too small to be definitive.

    The Baby Biome study is aiming to collect faecal samples from 80,000 babies.

    That will be a lot of soiled nappies to analyse, but it will be an unparalleled resource for interrogating the impact of decisions made around birth.

    Many of those will be out of parents’ hands.

    No doctor or parent would hold back on life-saving antibiotics because of an uncertain long-term impact.

    Breast milk feeds gut bacteria

    This study will let scientists see which microbes the body first hooks up, what that means years later and, tantalisingly, whether damaging relationships with the wrong bacteria can be repaired.

    The faecal samples will end up at the Wellcome Sanger Institute in Cambridge and in the hands of microbial enthusiasts such as Dr Trevor Lawley.

    “My latest favourite microorganism is Bifidobacterium,” he says.

    “It is one of the first bugs to colonise humans early in life, and we believe they feed off sugars in the breast milk.

    “So, there’s a very sophisticated evolutionary set-up where the bugs are passed from the mother to child and the mother nurtures that bug to establish the early microbiome.”

    Dr Lawley’s lab will be trying to uncover every microbe that colonises a newborn and what that means later in life.

    He thinks the end result of the project will be to change policy around avoidable antibiotic use and Caesarean sections.

    Or, alternatively, “maybe we could culture the bugs from the mums to purposefully colonise the babies to allow their microbiome to mature and develop properly” – in other words, a scientifically controlled version of vaginal seeding.

    So are some parents just ahead of the game?

    Prof Brocklehurst says: “At the moment some parents believe this hypothesis enough that they are doing their own vaginal seeding.

    “Now, there could be real downsides to that.”

    One concern is dangerous bugs could be transferred.

    Up to a quarter of women are thought to carry group-B strep in their vagina, and exposing babies to this bacterium could be fatal.

    Prof Brocklehurst says: “It too early to start introducing bacteria artificially into the baby until we’ve got a good handle on how likely this is to be the mechanism or not.”

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    Illustrations: Katie Horwich

‘World’s worst’ super-gonorrhoea man cured

A man in the UK who caught the world’s “worst-ever” case of super-gonorrhoea has been cured.

Sexual health doctors say he was “very lucky” and the case was a “major wake-up call for everybody”.

He picked up the superbug having sex with a woman in South East Asia, despite having a British partner.

It was the first-ever case of the infection being incurable with first choice antibiotics, but now two similar cases have been reported in Australia.

The original case came to light last month and was linked to travel earlier in the year.

The main antibiotic treatment – a combination of azithromycin and ceftriaxone – failed to treat the disease.

A detailed analysis of his infection suggested one last antibiotic might work and he has since been treated with ertapenem.

Dr Gwenda Hughes, the head of sexually-transmitted infections at Public Health England, said: “We are pleased to report that the case of multi-drug resistant gonorrhoea has been successfully treated.”

The public health body launched an investigation to track down any further cases – including in his British partner – but says the superbug has not spread in the UK.

Discussions between Public Health England, the World Health Organization and the European Centres for Disease Control agreed this was the most serious case of antibiotic-resistant gonorrhoea ever detected.

But now two “similar” cases have been discovered in Australia. One also had sex in South East Asia, the other reported no foreign travel.

Dr Hughes said they will be “challenging” to treat and were a “timely reminder” to everyone that super-gonorrhoea is likely to be more common in the future.

What is gonorrhoea?

The disease is caused by the bacterium Neisseria gonorrhoeae.

The infection is spread by unprotected vaginal, oral and anal sex.

Symptoms can include a thick green or yellow discharge from sexual organs, pain when urinating and bleeding between periods.

However, vaginal and rectal infections often have no symptoms.

An untreated infection can lead to infertility, pelvic inflammatory disease and can be passed on to a child during pregnancy.

Dr Olwen Williams, the president of the British Association for Sexual Health and HIV, said the case was a “major wake-up call for everybody”.

She told the BBC: “He was very lucky that he still had one remaining antibiotic that was used successfully.

“Our concern is in the future there might be no antimicrobials that will work.”

She said people needed to be aware that the risk of picking up superbugs is higher in countries that use antibiotics less carefully.

Antibiotics are available to buy over the counter in many countries around the world, unlike in the UK where a prescription from a doctor is needed.

It means the drugs are likely to be overused, driving up rates of resistance.

Dr Williams said: “We have to be aware when we travel that is potentially what we pick up.

“If you have unsafe sex anywhere in the world, get checked out when you come back before having sex with other partners.”

She also warned cuts to sexual health services were hitting “in a world where have to tackle multi-drug resistant gonorrhoea and rising incidence of syphilis” and that was a “significant concern”.

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New ban on epilepsy drug in pregnancy

An epilepsy drug that can damage unborn babies must no longer be prescribed to girls and women of childbearing age in the UK unless they sign a form to say that they understand the risks.

Drug regulator the MHRA says the new measures it’s introducing will keep future generations of children safe.

Those already on valproate medication should see their GP to have their treatment reviewed.

No woman or girl should stop taking it without medical advice though.

It is thought about 20,000 children in the UK have been left with disabilities caused by valproate since the drug was introduced in the 1970s.

Affected families have called for a public inquiry and compensation.

Epilepsy charities say one in five women on sodium valproate are unaware that taking it during pregnancy can harm the development and physical health of an unborn baby.

And more than one in four have not been given information about risks for their unborn child.

The MHRA has changed the licence for valproate, which means any doctor prescribing it will have to ensure female patients are put on a Pregnancy Prevention Programme, which means:

  • The patient can see her doctor every year to discuss the risks of this drug to an unborn baby
  • She signs an acknowledgement form at least every year
  • She is told about the importance of using contraception throughout treatment and having a pregnancy test if she thinks she could be pregnant

    If valproate is taken during pregnancy, up to four in 10 babies are at risk of developmental disorders, and approximately one in 10 are at risk of birth defects.

    Dr June Raine, from the MHRA, said: “Patient safety is our highest priority. We are committed to making sure women and girls are aware of the very real risks of taking valproate during pregnancy. However, we also know it is vitally important women don’t stop taking valproate without first discussing it with their doctor.

    “I would like to particularly thank the families involved in the Valproate Stakeholder Network who have shared their experiences and expertise with us. Their support will help keep future generations of children safe.”

    Simon Wigglesworth, deputy chief executive of Epilepsy Action, said: “We know there are still far too many women who haven’t been made aware of the potential risks of taking sodium valproate in pregnancy.

    “It is vitally important that healthcare professionals ensure that all women with epilepsy taking sodium valproate are reviewed in line with the new guidelines.”

    View comments

How bacteria are changing your mood

If anything makes us human it’s our minds, thoughts and emotions.

And yet a controversial new concept is emerging that claims gut bacteria are an invisible hand altering our brains.

Science is piecing together how the trillions of microbes that live on and in all of us – our microbiome – affect our physical health.

But even conditions including depression, autism and neurodegenerative disease are now being linked to these tiny creatures.

We’ve known for centuries that how we feel affects our gut – just think what happens before an exam or a job interview – but now it is being seen as a two-way street.

Groups of researchers believe they are on the cusp of a revolution that uses “mood microbes” or “psychobiotics” to improve mental health.

The study that ignited the whole concept took place at Kyushu University in Japan.

The researchers showed that “germ-free” mice – those that never came into contact with microbes – pumped out twice the amount of stress hormone when distressed than normal mice.

The animals were identical except for their microbes. It was a strong hint that the difference was a result of their micro-organisms.

“We all go back to that first paper for the first wave of neuroscientists considering microbes,” says Dr Jane Foster, a neuropsychiatrist at McMaster University in Canada.

“That really was very powerful for those of us who were studying depression and anxiety.”

It was the first hint of microbial medicine in mental health.

How could bacteria be altering the brain?

The brain is the most complex object in the known universe so how could it be reacting to bacteria in the gut?

  • One route is the vagus nerve, it’s an information superhighway connecting the brain and the gut.
  • Bacteria break down fibre in the diet into chemicals called short-chain fatty acids, which can have effects throughout the body.
  • The microbiome influences the immune system, which has also been implicated in brain disorders.
  • There is even emerging evidence that gut bugs could be using tiny strips of genetic code called microRNAs to alter how DNA works in nerve cells.

    There is now a rich vein of research linking germ-free mice with changes in behaviour and even the structure of the brain.

    But their completely sterile upbringing is nothing like the real world. We’re constantly coming into contact with microbes in our environment, none of us are germ-free.

    At Cork University Hospital, Prof Ted Dinan is trying to uncover what happens to the microbiome in his depressed patients.

    A good rule of thumb is a healthy microbiome is a diverse microbiome, containing a wide variety of different species living all over our bodies.

    Prof Dinan says: “If you compare somebody who is clinically depressed with someone who is healthy, there is a narrowing in the diversity of the microbiota.

    “I’m not suggesting it is the sole cause of depression, but I do believe for many individuals it does play a role in the genesis of depression.”

    And he argues some lifestyles that weaken our gut bacteria, such as a diet low in fibre, can make us more vulnerable.

    The microbiome

    • You’re more microbe than human – if you count all the cells in your body, only 43% are human
    • The rest is our microbiome and includes bacteria, viruses, fungi and single-celled archaea
    • The human genome – the full set of genetic instructions for a human being – is made up of 20,000 instructions called genes
    • But add all the genes in our microbiome together and the figure comes out at between two million and 20 million microbial genes
    • It’s known as the second genome and is linked to diseases including allergy, obesity, inflammatory bowel disease, Parkinson’s, whether cancer drugs work and even depression and autism

      More than half your body is not human

      Gut Instinct: Why I put my poo in the post

      Does vaginal seeding boost health?

      Why a faecal transplant could save your life

      It’s an intriguing concept – that an imbalance in the gut microbiome could be involved in depression.

      So scientists at the APC Microbiome centre, at University College Cork, started transplanting the microbiome from depressed patients to animals. It’s known in the biz as a trans-poo-sion.

      It showed that if you transfer the bacteria, you transfer the behaviour too.

      Prof John Cryan told the BBC: “We were very surprised that you could, by just taking microbiome samples, reproduce many of the features of a depressed individual in a rat.”

      This included anhedonia – the way depression can lead to people losing interest in what they normally find pleasurable.

      For the rats, that was sugary water they could not get enough of, yet “when they were given the microbiome from a depressed individual, they no longer cared”, says Prof Cryan.

      Listen to The Second Genome on BBC Radio 4.

      The next episode airs at 11:00 BST on Tuesday April 24, repeated 21:00 BST Monday April 30 and on the BBC iPlayer

      Similar evidence – linking the microbiome, the gut and the brain – is emerging in Parkinson’s disease.

      It is clearly a brain disorder. Patients lose control over their muscles as brain cells die and it leads to a characteristic tremor.

      But Prof Sarkis Mazmanian, a medical microbiologist from Caltech, is building the case that gut bacteria are involved.

      “Classical neuroscientists would find this as heresy to think you can understand events in the brain by researching the gut,” he says.

      He has found “very powerful” differences between the microbiomes of people with Parkinson’s and those without the disease.

      Studies in animals, genetically hardwired to develop Parkinson’s, show gut bacteria were necessary for the disease to emerge.

      And when stool was transplanted from Parkinson’s patients to those mice, they developed “much worse” symptoms than using faeces sourced from a healthy individual.

      Prof Mazmanian told the BBC: “The changes in the microbiome appear to be driving the motor symptoms, appear to be causal to the motor symptoms.

      “We’re very excited about this because it allows us to target the microbiome as an avenue for new therapies.”

      The evidence linking the microbiome and the brain is as fascinating as it is early.

      But the pioneers of this field see an exciting prospect on the horizon – a whole new way of influencing our health and wellbeing.

      If microbes do influence our brains then maybe we can change our microbes for the better.

      Can altering the bacteria in Parkinson’s patients’ guts change the course of their disease?

      There is talk of psychiatrists prescribing mood microbes or psychobiotics – effectively a probiotic cocktail of healthy bacteria – to boost our mental health.

      Dr Kirsten Tillisch, at University of California, Los Angeles, told me: “If we change the bacteria can we change the way we respond?

      But she says we need far bigger studies that really probe what species, and even sub-species, of bacteria may be exerting an effect on the brain and what products they are making in the gut.

      Dr Tillisch said: “There’s clearly connections here, I think our enthusiasm and our excitement is there because we haven’t had great treatments.

      “It’s very exciting to think there’s a whole new pathway that we can study and we can look and we can help people, maybe even prevent disease.”

      And that’s the powerful idea here.

      The microbiome – our second genome – is opening up an entirely new way of doing medicine and its role is being investigated in nearly every disease you can imagine including allergies, cancer and obesity.

      I’ve been struck by how malleable the second genome is and how that is in such stark contrast to our own DNA.

      The food we eat, the pets we have, the drugs we take, how we’re born… all alter our microbial inhabitants.

      And if we’re doing that unwittingly, imagine the potential of being able to change our microbiome for the better.

      Prof Cryan said: “I predict in the next five years when you go to your doctor for your cholesterol testing etc, you’ll also get your microbiome assessed.

      “The microbiome is the fundamental future of personalised medicine.”

      Follow James on Twitter.

      Illustrations: Katie Horwich

Parents facing ‘unfair child abuse claims’ over bruising

Parents are being investigated for possible child abuse because of the misinterpretation of guidelines on bruising in babies, it’s claimed.

Official guidelines from health watchdog NICE for hospital workers suggest such bruising is very uncommon.

University of Central Lancashire research suggested the guidelines mean social services are investigating parents too often.

Its research said more than a quarter of babies are bruised accidentally.

One mother had her baby removed from her care for a year by social services, until its bruising was found to have been caused by a medical condition.

‘Exaggerated effects’

Lead researcher Prof Andy Bilson told the BBC’s Victoria Derbyshire programme that “social workers are in danger of having to take decisions based on really misleading interpretations of research”.

The NICE guidelines are used by local authorities to draw up their own policies.

Some 91 of the 152 councils in England have specific guidance on how staff should respond to possible abuse.

More than three-quarters (77%) of these do not give front-line staff such as nurses, health visitors and GPs the freedom to make judgements about the causes of a bruise, the university’s researchers said.

In five local authorities, a formal child protection investigation must be undertaken when a single bruise in a pre-mobile child – who cannot crawl or walk – is discovered.

This is despite research from 2015 showing accidental bruising occurred in 27% of pre-mobile babies – those that cannot crawl or walk – monitored over a seven to eight-week period, researchers said.

Chelsea and Theo’s story

Chelsea Kirtley had her baby Theo removed from her and the father’s care for more than a year.

She initially took him to the GP worried that the bruising was a sign of meningitis.

But when further marks appeared, Stockton Council social services accused them of harming their child.

“It felt they were out to get us,” Chelsea explained. “We got escorted by police off the hospital ward, with all the [other] parents looking at us.”

Her son was placed into the care of his aunt, and then his grandmother.

The case was only dropped after Ms Kirtley had Theo examined by a geneticist, who diagnosed him with hypermobility syndrome – a condition that causes people to bruise easily.

But she says the stress caused her to split from the father and leave her job.

She was made homeless and now lives with Theo and her mother in a hostel.

The council said it “relied heavily on medical views throughout” its assessment of Theo, and that the safety of a child always has to be its number one consideration.

The tragedies of children such as Victoria Climbie and Baby P, in which warning signs were missed by social workers, are thought to have changed how local authorities deal with cases of bruising.

Labour MP Emma Lewell-Buck used to be a social worker in Sunderland, which has some of the strictest guidance.

“I never came across a case where a [pre-mobile] baby had a bruise, and that bruise was purely accidental,” she said.

“I think you should always err on the side of caution.”

She said the public would want social services to “do the right thing and make sure they had a full medical assessment to find out whether or not this was deliberate”.

‘Other dangers’

Prof Bilson acknowledges social workers have a duty to look into incidents of bruising, but said some parents would be put off from taking their children to see a GP for fear of being investigated – stopping the child from getting the medical care it needs.

“If this puts into people’s minds even a hesitation of taking their child to a doctors, there’s a real chance sooner or later some child will die due to this policy,” he said.

NICE did not comment on the claim its guidelines could be misleading.

It said its original advice was aimed at medical professionals working in hospitals.

New guidance has been issued by NICE aimed more at social workers and teachers.

Watch the BBC’s Victoria Derbyshire programme on weekdays between 09:00 and 11:00 on BBC Two and the BBC News Channel.

Fake cancer causes belief ‘rife’, research suggests

Drinking from plastic bottles and using microwave ovens are some of the fake causes of cancer people believe, research suggests.

In a survey of 1,330 people in England, published in the European Journal of Cancer, most people correctly said smoking was a cause.

But increasing numbers are getting the risk factors wrong.

Smoking, being overweight and overexposure to UV radiation are the biggest preventable causes of cancer.

Cancer Research UK said about four in 10 cases of cancer could be prevented through lifestyle changes and it was important to have the right information to “separate the wheat from the chaff”.

Researchers at University College London and the University of Leeds carried out the survey and found that more than 40% wrongly thought that stress and food additives caused cancer.

One-third incorrectly believed that electromagnetic frequencies (35%) and eating genetically modified (GM) food (34%) were risk factors, while 19% thought microwave ovens and 15% said drinking from plastic bottles caused cancer, despite a lack of good scientific evidence.


Smoking was, correctly, selected by 88% of those surveyed, 80% picked passive smoking and 60% said sunburn were causes of cancer – all proven.

Believing in fake causes of cancer did not mean people were more likely to have risky lifestyle habits, but those who were better informed about the proven causes of cancer were more likely not to smoke, the study found.

They were also more likely to eat more fruit and vegetables.

Dr Samuel Smith, from the University of Leeds, said: “It’s worrying to see so many people endorse risk factors for which there is no convincing evidence.

“Compared to past research, it appears the number of people believing in unproven causes of cancer has increased since the start of the century, which could be a result of changes to how we access news and information through the internet and social media.”

He added: “It’s vital to improve public education about the causes of cancer if we want to help people make informed decisions about their lives and ensure they aren’t worrying unnecessarily.”

Clare Hyde, from Cancer Research UK, said: “There is no guarantee against getting cancer – but by knowing the biggest risk factors we can stack the odds in our favour to help reduce our individual risk of the disease, rather than wasting time worrying about fake news.”

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