Researchers discovered why the liver of many fatty liver patients is damaged by alcohol, even though these people do not drink alcohol. But where does the alcohol come from?
Alcohol can be formed in the body, which then leads to fatty liver
Anyone who drinks a lot of alcohol runs the risk of developing fatty liver. In the so-called non-alcoholic fatty liver (NAFLD), no alcohol is required to form a fatty liver. Here other causes lead to fat storage in the liver, e.g. being overweight with regularly excessive calorie intake, lack of exercise or high carbohydrate consumption in the form of frequent flour and sugar dishes, fruit juices or lemonades.
However, there are also people who are neither overweight nor eat too much sugar, let alone drink alcohol, and still have a fatty liver. What is the reason for that?
Researchers discovered something strange: alcohol could be detected in over 60% of patients who suffered from non-alcoholic fatty liver, i.e. who had fatty liver, even though they hardly drank alcohol. Where in the body of these patients is the alcohol formed?
Certain gut bacteria produce alcohol
“We were very surprised when we found that there are certain gut bacteria that can produce alcohol,” said study author Jing Yuan of the Capital Institute of Pediatrics in Beijing ( 2 ). “If the amounts of alcohol produced in this way are finally so large that they can no longer be broken down by the body, alcoholic fatty liver can develop, even though you don’t drink any alcohol at all.”
Yuan and her team discovered the connection between gut bacteria and non-alcoholic fatty liver in a patient who had severe liver damage due to a rare condition called an auto-brewery syndrome.
What is auto-brewery Syndrome?
In this intestinal disease, it is yeast fungi that multiply excessively (candidiasis) as a result of poor nutrition, a weakened immune system or even after antibiotic therapy and produce large amounts of alcohol after meals rich in sugar. Those affected are often “drunk”, have to live with social ostracism through no fault of their own, since everyone thinks they are alcoholics and risk serious liver damage if the disease is not recognized in time.
60 percent of fatty liver patients have alcohol-producing intestinal bacteria
Not in all patients however is it yeast. Therefore antifungal medication don’t help either. A stool analysis showed that there were certain strains of Klebsiella pneumonia that are capable of producing large amounts of alcohol.
K. pneumonia is basically a harmless gut bacterium that does no harm. In this particular case, however, they were strains that could produce four to six times more alcohol than Klebsiella strains found in healthy individuals.
Following this discovery, Yuan’s team checked the gut flora of 43 people with non-alcoholic fatty liver disease (NAFLD) and 48 healthy people. Indeed, 60% of NAFLD patients harbored strains of Klebsiella that produced high or moderate levels of alcohol. In the group of healthy participants, these strains were found in only 6%.
The study was published in September 2019 in the journal Cell Metabolism ( 1 ).
Liver can recover if the intestines are sanitized
In order to prove that K. pneumonia is really responsible for the development of fatty liver, the intestines of germ-free mice were colonized with the alcohol-producing Klebsiella strains. The mice developed a fatty liver in the first month, and after two months the liver tissue began to harden, indicating sustained liver damage. The abstinent mice fared just as badly as the mice that had been given alcohol.
If the Klebsiella group was given an antibiotic that killed the alcohol-producing bacteria in the intestine, the animals made a full recovery and their livers were able to regenerate.
Test blood for alcohol in non-alcoholic fatty liver!
“Non-alcoholic fatty liver can have many different causes,” Yuan explains. “Our study shows that certain intestinal bacteria such as K. pneumonia are very likely one of these reasons.” While one can decide for or against alcohol consumption, in the case of the intestinal flora disorder described, one is practically a victim of one’s intestinal bacteria and their alcohol production. Yes, the body is constantly exposed to certain amounts of alcohol in this way.
It is not yet known why these alcohol-producing intestinal bacteria of all things colonize one person and not the other and should be the subject of further research.
In the case of non-alcoholic fatty liver, the patient could be made to drink a glucose solution and a short time later their blood tested for alcohol. If the result is positive (of course without the patient having actually drunk alcohol beforehand), the focus of therapy should be on the intestines. Because the sooner a fatty liver is recognized and treated, the better the liver can recover.
Probiotics could help with non-alcoholic fatty liver
As early as 2014, a rat study showed that the administration of probiotics (beneficial intestinal bacteria) promoted the breakdown of fat from the liver. Rehabilitation of the intestinal flora should therefore always be part of the therapy concept for a fatty liver. After all, the goal here is: to colonize useful intestinal bacteria and displace harmful intestinal bacteria (which undoubtedly also include alcohol-producing bacteria).
The measures we recommend for fatty liver can also be helpful for that form of fatty liver in which alcohol-producing intestinal bacteria are involved: rehabilitation of the intestinal flora and a sugar-free diet.
