How Does Fatty Liver Disease Affect Brain Health? Study Finds Clues

The study examines the link between non-alcoholic fatty liver disease (NAFLD) and brain dysfunction. It was carried out by feeding two different diets to mice.

When fat accumulates in the liver, it causes a decrease in oxygen to the brain and inflammation to brain tissue, a new study has found. This is significant because both these effects — decrease of oxygen supply to the brain and inflammation of brain tissue — are known to lead to the onset of severe brain diseases.

The study was carried out by scientists at the Roger Williams Institute of Hepatology, affiliated to King’s College London and the University of Lausanne. It was conducted in collaboration with Inserm (the French National Institute of Health and Medical Research) and the University of Poitiers in France, and has been published in the Journal of Hepatology.

The study examines the link between non-alcoholic fatty liver disease (NAFLD) and brain dysfunction. It was carried out by feeding two different diets to mice. Half of the mice were fed a diet that had 10 per cent or less fat in the calorie intake, while the other half were fed a diet whose calorie intake contained 55 per cent fat. The latter diet was intended to match the fat content in processed foods and sugary drinks.

The two parallel diets were continued for 16 weeks, after which a series of tests was conducted. The tests compared how these diets affected the body in general, and the liver and the brain in particular. The mice that consumed higher levels of fat were all considered obese, and developed NAFLD, insulin resistance and brain dysfunction. 

Also, the brains of mice with NAFLD suffered from lower oxygen levels. This is because the disease affects the number and thickness of the brain blood vessels, which deliver less oxygen to the tissue. Also, specific cells consuming more oxygen while the brain is becoming inflamed, King’s College London explained in a press release. These mice were also more anxious and showed signs of depression, the release said.

The mice that had consumed the healthy diet, on the other hand, did not develop NAFLD or insulin resistance. They behaved normally, and their brain was healthy, the release said.

“This research emphasises that cutting down the amount of sugar and fat in our diets is not only important for tackling obesity, but also for protecting the liver to maintain brain health and minimise the risk of developing conditions like depression and dementia during ageing, when our brain becomes even more fragile,” the release quoted lead author Dr Anna Hadjihambi as saying.