Non-alcoholic fatty liver disease (NAFLD) is the type of chronic liver disease with the highest incidence in my country. Currently, there are more than 150 million patients in our country, of which 10-20% will further develop into non-alcoholic steatohepatitis (NASH), which is mainly characterized by inflammatory reaction. and hepatocellular damage, often accompanied by fibrosis. NASH progresses rapidly and has a higher risk of developing serious liver diseases such as cirrhosis and liver cancer.
Vitamin B₃, also known as nicotinyl, is a water-soluble vitamin that plays a variety of important physiological functions in the human body. Early research shows that vitamin B₃ participates in the energy metabolism process in the body, promotes the metabolism of skin cells, and also has a certain antioxidant effect. ​
Although there is currently no drug treatment for NAFLD, lifestyle changes and dietary strategies are crucial interventions.
On September 25, 2023, researchers from the School of Public Health of Sun Yat-sen University published a research paper titled "Association between Dietary Niacin Intake and Nonalcoholic Fatty Liver Disease: NHANES 2003-2018" in the journal "Nutrients".

The study showed that vitamin B₃ supplementation was associated with a lower risk of non-alcoholic fatty liver disease, with those with the highest niacin intake having a 31% lower risk of developing non-alcoholic fatty liver disease compared with those with the lowest niacin intake.
In the study, researchers analyzed 12,355 participants aged 20 years and older who participated in the 2003-2018 National Health and Nutrition Examination Survey (NHANES). Dietary niacin intake was assessed through a dietary questionnaire. Daily: <16.3mg, 16.4-22.1mg, 22.2-29.1mg, >29.2mg. The definition of fatty liver was established based on the American Fatty Liver Index. The correlation between dietary niacin and NAFLD was analyzed.
Overall, 4,378 people with NAFLD were recorded during the 16-year study period. Compared with non-NAFLD participants, NAFLD patients were older, more likely to be male, and had higher BMI and total energy intake.
The analysis found that compared with those with the lowest niacin intake, participants with the second, third, and fourth highest niacin intakes had a 16%, 20%, and 31% lower risk of NAFLD, respectively.

In addition, the researchers analyzed the relationship between daily niacin intake and NAFLD based on the recommended daily intake (RDA) and tolerable upper limit (UL) of niacin. The recommended dosage is 16 mg per day for men and 14 mg for women. The upper limit of tolerance for men and women is 35 mg per day.
The study found that people who consumed less than 16 mg of niacin per day had a 92% increased risk of NAFLD, compared with those who consumed 16-35 mg per day, while those who consumed more than 35 mg of niacin per day had a 92% increased risk of developing NAFLD. The risk of NAFLD was reduced by 13%.

Finally, the researchers also found that the effect of niacin intake on NAFLD was moderated by hypertension. Among people with hypertension, those with the highest niacin intake had only a 4% lower risk of NAFLD, while among non-hypertensive people, those with the highest niacin intake had a 46% lower risk of NAFLD.
Still, the study was observational and could only draw correlations but not prove causation, the researchers said.
Taken together, the results suggest that higher dietary niacin intake is associated with lower incidence of NAFLD, that daily niacin intake greater than 22.2 mg significantly reduces the risk of NAFLD, and that those with the highest niacin intake develop NAFLD. The risk is reduced by 31%.