Meat-eaters may be at higher risk of developing multiple sclerosis than vegetarians, a small study suggests.
Researchers have linked bacterial changes in the gut — closely tied to the immune system — to the autoimmune disease.
They speculated these changes, linked to eating meat, may set off a chain reaction that could contribute to or worsen the condition.
MS is an incurable condition where the immune system mistakenly causes nerve damage to the brain and spinal cord.
This damage causes the nerves to misfire and malfunction, like a damaged electrical system, leaving suffers struggling to walk and see properly.
The exact trigger which prompts the immune system to attack is still unknown but the new research on gut bacteria offers a new area to investigate.
The gut microbiome, a name for the vast collection of microorganisms in the digestive system, has been linked to variety of conditions in recent years.
They are thought to play a role in everything from helping digest food and preventing infection, to training the immune system.
Scientists say they have discovered a possible link between eating meat and and multiple sclerosis with a carnivores heavy diet influencing which species of gut bacteria thrive
In what they said was the first study of its kind, scientists from the University of Connecticut and Washington University analysed the gut microbiome, immune systems, diet, and blood of 25 MS patients.
They then compared this with data from 24 healthy people as a control group.
Author of the study, Dr Yanjiao Zhou, said they found levels of types of gut bacteria to be associated with both MS, and the severity of people’s condition.
WHAT IS MULTIPLE SCLEROSIS?
Multiple sclerosis (known as MS) is a condition in which the immune system attacks the body and causes nerve damage to the brain and spinal cord.
It is an incurable, lifelong condition. Symptoms can be mild in some, and in others more extreme causing severe disability.
MS affects 2.3 million people worldwide – including around one million in the US, and 100,000 in the UK.
It is more than twice as common in women as it is in men. A person is usually diagnosed in their 20s and 30s.
The condition is more commonly diagnosed in people of European ancestry.
The cause isn’t clear. There may be genes associated with it, but it is not directly hereditary. Smoking and low vitamin D levels are also linked to MS.
Symptoms include fatigue, difficulty walking, vision problems, bladder problems, numbness or tingling, muscle stiffness and spasms, problems with balance and co-ordination, and problems with thinking, learning and planning.
The majority of sufferers will have episodes of symptoms which go away and come back, while some have ones which get gradually worse over time.
Symptoms can be managed with medication and therapy.
The condition shortens the average life expectancy by around five to 10 years.
‘But what is really interesting is how these systems connect with each other, and how diet is involved in these connections,’ she said.
The analysis found people who ate meat had lower levels of bacteroides thetaiotaomicron, a species of gut bacteria associated with digesting vegetables.
They also found that people with MS had a higher meat consumption, which led the team to theorise there was a connection.
Furthermore, blood samples from MS patients showed higher levels of an immune system cell called T-helper 17, a type T-cell that helps other cells identify targets to attack.
Combining the findings, they suspected that something is going wrong with MS patients’ gut bacteria that causes it to disassociate from the immune system, prompting it to respond as if the body was under attack from an infection.
This leads the body to increase production of T-helper 17, which the researchers say could then lead to the nerve damage of MS.
The scientists were keen to highlight that this association was not simple, as plenty of healthy people eat meat without problems.
But they added the data from their study did suggest a connection between MS and meat consumption.
However, going vegetarian or vegan is now known to cause several deficiencies that can damage health.
People who eat no meat are often short of vitamin B12 and iron, which can lead tiredness and mental health problems without supplementation.
This is why doctors recommend a balanced diet full of a variety of foods.
Dr Laura Piccio, who was also involved in the study, said their analysis opened up a new potential avenue for further research.
‘This is the first study using an integrated approach to analyse the interplay between diet, gut microbiome, the immune system and metabolism and their contribution to disease pathogenesis and progression in people with MS,’ she said.
‘It opens a new modality to address future scientific questions by not looking at one individual factor, but at their complex interactions.’
Publishing their findings in the journal EBioMedicine, the team said that in the future they want to expand their research to include more people, particularly those with more severe forms of MS.
They said they hope this lead them to eventually understand the relationship between the diet, gut bacteria, and the immune response, to help prevent and mitigate MS symptoms.
Doctors did not detail what kind of meat participants were eating, whether it was red meat, poultry, or fish, and if it was processed.
The research is the latest in an ongoing scientific tug-of-war debate about the role of meat in our diet.
Some studies have said eating any kind of meat regularly increases people’s risk of developing heart diseases, one of the biggest killer in the US and UK.
But other research has touted the benefits of a carnivorous diet on both muscle and mental health.
The NHS advises that meat is a good source of protein, vitamins and minerals, but people should only eat a maximum of 70g of red or processed meat, like bacon, per day.
Charities estimate that 130,000 people in the UK have MS, with 7,000 people newly diagnosed each year. The cost of caring for MS in Britain has been calculated to be £1.4billion per year.
In the US, a million people are thought to be living with MS, with the cost of care there estimated to be a whopping $28billion annually.
What exactly triggers MS is an ongoing subject of scientific debate.
But, a recent study of 10million US soldiers suggested the virus behind glandular fever may be the biggest cause of the condition.
Earlier this month Harvard scientists said they have ‘compelling evidence’ the Epstein-Barr virus (EBV) – which causes the ‘kissing disease’/mononucleosis –was to blame for majority of MS cases.
Glandular fever may be the biggest cause of multiple sclerosis
Glandular fever may be the biggest cause of multiple sclerosis, a major study has concluded.
Harvard scientists say they have ‘compelling evidence’ the Epstein-Barr virus (EBV) – which causes the ‘kissing disease’/mononucleosis – is to blame.
They tracked the prevalence of MS among 10million soldiers in the US military over the course of two decades. Volunteers regularly had blood tests taken to see if they had EBV.
Almost 1,000 were diagnosed with the crippling condition, which can leave victims struggling to walk and see.
Analysis of the patients revealed that those who had EBV were 32 times more likely to get MS. No other infection raised the risk.
Professor Alberto Ascherio, study author, said: ‘The hypothesis that EBV causes MS has been investigated by our group and others for several years.
‘But this is the first study providing compelling evidence of causality.
‘This is a big step because it suggests that most MS cases could be prevented by stopping EBV infection.’
He added: ‘Targeting EBV could lead to the discovery of a cure for MS.’