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

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