Even people who don't drink can get liver disease: Scientists find 60% of 'human foie gras' patients carry a bacteria that produces enough alcohol to damage the crucial organ

Even people who do not drink can still develop liver disease caused by alcohol, research suggests.

Scientists analysed the microbiomes of 43 patients with non-alcoholic fatty liver disease (NAFLD), dubbed 'human foie gras'.

They found 60 per cent of the patients had the bacteria Klebsiella pneumonia that produced either high or medium levels of alcohol.

In comparison, the figure was just six per cent among the other 48 participants who were studied, all of whom were healthy. 

Researchers in China worry some K. pneumonia strains 'overload the body', leaving it unable to break down the alcohol caused by the bacteria. 

The scientists became intrigued in the bacteria when a 27-year-old man sought help for bouts of unexplained drunkenness in 2014.

Insisting he was not a closet drinker, the man provided stool samples, which showed he had 900 times more of K. pneumonia in his gut than the average person. 

The research was carried out by the Capital Institute of Paediatrics in Beijing. 

'We were surprised bacteria can produce so much alcohol,' lead author Dr Jing Yuan said.

'When the body is overloaded and can’t break down the alcohol produced by these bacteria you can develop fatty liver disease even if you don’t drink.'

NAFLD describes a range of conditions caused by a build-up of fat in the liver. A healthy liver should have little or not fat. 

Up to one in three people in the UK are thought to have the early stages of NAFLD, NHS statistics show.

In the US, between 30 and 40 per cent of adults have NAFLD, according to the National Institute of Diabetes and Digestive and Kidney Diseases.

Early stage NAFLD is usually harmless, however, it can lead to inflammation, known as non-alcoholic steatohepatitis. 

This can then develop into fibrosis - scar tissue formation - and then cirrhosis - when the liver shrinks and is permanently damaged, which can lead to liver failure or cancer.

When the scientists came across the 27-year-old man, they initially thought he may have auto-brewery syndrome, Science reported.

This rare condition occurs when the body turns sugary and starchy foods into alcohol. However, the go-to treatment of anti-fungal drugs did nothing to ease his symptoms.

A biopsy later showed the man had severe NAFLD. Keeping him under observation, the scientists noticed when he ate a sugary meal, his blood sugar levels shot up to the equivalent of doing '15 shots of 40 per cent whiskey'. 

A stool sample analysis showed 18.8 per cent of the bacteria in his gut was K. pneumonia - 900 times more than normal.  

K. pneumonia is generally considered harmless when in the gut. If the bacteria gets into other parts of the body, however, it can lead to pneumonia, wound infections and even blood poisoning.

WHAT IS NON-ALCOHOLIC FATTY LIVER DISEASE? 

Non-alcoholic fatty liver disease is caused by too much fat being stored in the organ's cells.

The disease can cause scarring and irreversible damage to the liver, and can progress to cirrhosis (scarring) and organ failure.

Fatty liver disease usually causes no signs and symptoms, but they can include an enlarged liver, fatigue and abdomen pain.

The illness is caused by obesity, insulin resistance, high blood sugar and high levels of fat in the blood.

Risk of contracting the disease is increased in people with high cholesterol, fat concentrated in the abdomen, sleep apnea and Type 2 diabetes.

A nutritious diet, maintaining a healthy weight and exercising regularly can reduce the risk of fatty liver disease.

Some strains of the bug are also known to produce alcohol, with the amounts they make varying. 

To learn more, the scientists analysed the stool samples of around 40 people with and without NAFLD. 

Results, published in the journal Cell, confirmed a link between K. pneumoniae and the condition.

Probing further, the team fed either K. pneumoniae or alcohol to mice. 

Four weeks later, both groups of rodents showed signs of liver damage. 

By the end of the second month, the animals had scarring on their livers, a sign of long-term damage.

'These bacteria damage your liver just like alcohol, except you don’t have a choice,' Dr Yuan said. 

When the mice were given a virus that kills K. pneumoniae, their NAFLD reversed, suggesting the condition may be treatable if caught early enough.

The scientists also noted the animals did not act intoxicated unless they were given a high dose of glucose beforehand.

Giving patients a sugary solution before testing their blood alcohol levels could therefore identify those carrying K. pneumoniae. 

'Patients who carry these bacteria would have a detectable amount of alcohol in their blood after drinking a simple glucose solution,' Dr Yuan said. 

It is unclear why some people have high-alcohol producing K.pneumonia in their gut and others do not. The scientists plan to research this further.

'It's likely that these particular bacteria enter people's body via some carriers from the environment, like food,' co-author Dr Di Liu said.

'But I don't think the carriers are prevalent, otherwise we would expect much higher rate of NAFLD. 

'Also, some people may have a gut environment that's more suitable for the growth and colonisation of K. pneumoniae than others because of their genetics.'

The scientists hope their study will enable NAFLD to be treated and even prevented earlier.

'In the early stages, fatty liver disease is reversible,' Dr Yuan said. 'If we can identify the cause sooner, we could treat and even prevent liver damage.' 

The initial patient is said to be doing well after taking antibiotics and changing his diet.