Fish oil supplement use is linked to a lower risk of severe fatty liver disease. Digest
Non-alcoholic fatty liver disease (NAFLD), now usually termed metabolic dysfunction-associated steatotic liver disease (MASLD), affects about one in four people worldwide and can progress to serious liver injury and even liver cancer. Because there are only limited pharmacologic options to prevent its progression, researchers are also looking closely at diet and supplements as possible tools. A new large study examined whether people who regularly take fish oil supplements face a lower risk of developing severe forms of this disease.
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Using data from the UK Biobank, investigators followed 488,888 adults aged 40 to 69 for an average of 12.3 years. At the start of the study, participants reported whether they regularly used fish oil supplements. The researchers then tracked hospitalizations and deaths linked to severe NAFLD. They also measured blood markers related to metabolism and inflammation, and analyzed whether genetic differences in omega-3 metabolism changed the results.
- Over the study period, 5,671 participants developed severe NAFLD based on hospital or mortality records.
- After adjusting for age, sex, body mass index (BMI), lifestyle, diet quality, medical history, and other factors, regular fish oil users had a 7% lower risk of severe NAFLD than non-users.
- Fish oil use was linked to lower blood levels of the proteins C-reactive protein (CRP) and cystatin C, and higher levels of high-density lipoprotein cholesterol (HDL-C).
- Statistical analyses suggested that these biomarkers together may help explain part of the association, with cystatin C accounting for 10%, CRP for 8.8%, and HDL-C for 7.5% of the link.
- The association looked similar regardless of the omega-3 metabolism genetic variants the researchers tested.
NAFLD is driven by intertwined problems in lipid metabolism, insulin resistance, and chronic low-grade inflammation. Elevated CRP reflects inflammatory signaling that worsens insulin resistance and promotes progression from simple fat accumulation to inflammatory liver injury. HDL-C can support cholesterol removal and have anti-inflammatory effects, yet it is often reduced or dysfunctional in NAFLD, contributing to liver fat buildup. Cystatin C is linked to metabolic disturbances and inflammation, both central to disease progression. Together, these pathways suggest that omega-3 fatty acids may lower severe NAFLD risk by simultaneously improving inflammation control, lipid handling, and metabolic balance.
The study relied on self-reported supplement use at a single time point, did not capture dose or duration, and identified only severe cases that led to hospitalization or death. Even so, the scale and long follow-up strengthen the findings that fish oil supplementation may meaningfully reduce the burden of severe NAFLD. In this clip, Dr. Bill Harris discusses the impact omega-3 levels have on the risk of death from cardiovascular disease, cancer, and other diseases.