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The link between non-alcoholic fatty liver disease and vitamin B12

The link between non-alcoholic fatty liver disease and vitamin B12Many people unwittingly suffer from a disease called non-alcoholic fatty liver disease, which is related to overweight and diabetes. The diet plays a major role, and a Chinese study shows that vitamin B12 is of particular importance. The scientists believe that the body’s vitamin B12 metabolism holds a therapeutic potential in relation to detecting and treating the disease and the complications that follow in the wake of it.

It is believed that around 25 percent of the world’s population suffers from non-alcoholic fatty liver disease (NAFLD), a condition characterized by fat accumulation in the liver (steatosis). The disease progresses slowly, so many people have it without being aware of it. Over time, many people develop a type of liver inflammation known as non-alcoholic steatohepatitis (NASH), which can result in liver scarring (fibrosis). It is a critical condition that affects most cellular processes, and there are currently no effective methods for diagnosing or treating liver fibrosis.
Non-alcoholic fatty liver disease is often linked to overweight and metabolic syndrome, a condition characterized by elevated cholesterol levels, insulin resistance, and hypertension. Metabolic syndrome is an early stage of type 2 diabetes. The leading cause of death among these patients is cardiovascular disease, and oxidative stress is major factor here.
In addition, non-alcoholic fatty liver increases the risk of cirrhosis and primary liver cancer. Because non-alcoholic fatty liver disease is linked to so many different complications and a risk of early death, doctors have increasingly needed to find new biomarkers to help them identify the disease, especially with relation to advanced liver fibrosis.
Earlier research has shown that blood levels of vitamin B12 and related markers change in patients with NAFLD. However, the studies have different limitations, which is why the Chinese scientists wanted to look closer at the link.

Vitamin B12 metabolism and its functions in the body

Vitamin B12 (cobalamin) is only found in animal foods such as meat, fish, eggs, and dairy products. B12 is important for the blood formation, nervous system, and our cognitive functions. In the body, vitamin B12 is converted into two active coenzymes (deoxyadenosylcobalamin and methylcobalamin), both of which are involved in lipid and carbohydrate metabolism. Vitamin B12, folic acid, and vitamin B6 are important for our ability to convert homocysteine into other amino acids. If blood levels of homocysteine are too high it increases our risk of oxidative stress and cardiovascular disease.
Vitamin B12 is also important for the metabolism of an enzyme called methylmalonyl-coenzyme A (MMA). Abnormal levels of MMA serve as a specific marker of vitamin B12 deficiency. Lack of vitamin B12 and folic acid that is often seen in combination may be caused by many different factors such as ageing processes, diet, poor nutrient absorption, and use of medicine.
The actual need for vitamin B12 and folic acid varies from person to person. According to the scientists behind the new study, biomarkers such as homocysteine and MMA are therefore more sensitive markers of metabolic processes that require the presence of vitamin B12 and folic acid. The scientists therefore wanted to study different biomarkers specifically in relation to non-alcoholic fatty liver disease and advanced liver fibrosis.

The study revealed a new potential for diagnosis and treatment

The researchers collected data from the large NHANES population study (National Health and Nutrition Examination Survey) that was carried out in the period between 1999-2004. The new study included more than 8,000 people with or without non-alcoholic fatty liver disease. NAFLD was diagnosed with help from the so-called fatty liver index (FLI). Participants with a risk of advanced liver fibrosis were assessed with help from the so-called NAFLD fibrosis score (NFS).
The scientists looked specifically at the relation between NAFLD, advanced liver fibrosis, and blood levels of vitamin B12, folic acid, homocysteine, MMA (methylmalonyl-coenzyme A), and folic acid in the red blood cells. Forty-two percent of the participants had non-alcoholic fatty liver disease, and they had higher levels of folic acid in the red blood cells and less folic acid and less vitamin B12 in their blood serum compared with those without NAFLD. Patients with advanced liver fibrosis also had higher levels of homocysteine and MMA.
In all participants, especially those with non-alcoholic fatty liver disease, levels of homocysteine and MMA were linked to an increased risk of advanced liver fibrosis. Therefore, the scientists concluded that the measurement of vitamin B12 levels and related biomarkers could be useful as clinical methods for assessing the progression of NAFLD and liver fibrosis. Although more studies are needed, vitamin B12 and the different biomarkers also have therapeutic potential in the prevention and treatment of complications such as non-alcoholic steatohepatitis (NASH) and advanced liver fibrosis.

More information about diet, nutrients, and NAFLD

A Chinese study has demonstrated that vitamin C can also improve liver function in people with NAFLD. It is a good idea to reduce your carbohydrate intake because large quantities of carbohydrate can burden the liver and turn it into a virtual fat factory. This was demonstrated in a Danish study from 2019. Lack of vitamin D is also linked to NAFLD and overweight, according to Italian research. Read more:

»Higher dietary vitamin C intake can improve your liver function and blood sugar levels«

»A new view on vitamin D deficiency, fatty liver and overweight«


Li Li et al. The Association between Non-Alcoholic Fatty Liver Disease (NAFLD) and advanced Fibrosis with Serological B12 Markers: results from the NHANES 1999-2004. Nutrients 9 March 2022

Xiaoqin Luo et al. Dietary Vitamin C Intake is Associated with Improved Liver Function and Glucose Metabolism in Chinese Adults. Frontiers in Nutrition 31 January 2022

Luigi Barres et al. E New Light on Vitamin D in Obesity: A Novel Association with Trimethylamine- N-Oxide (TMAO). Nutrients 2019

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