The role of nutrition in liver cancer risk has been underrepresented in research, particularly compared to risk factors such as chronic infection with hepatitis B virus (HBV) or hepatitis C virus (HCV). Yet, some studies have indicated that n-3 polyunsaturated fatty acid (n-3 PUFA) may inhibit the promotion and progression stages of carcinogenesis. Fish is a source rich in n-3 PUFA, making it an ideal factor for analysis.
A new study in PLOS ONE reviewed published studies on the role of total fish intake and risk of primary liver cancer in case-control and cohort studies. Ten studies were analyzed, with all but one study hospital-based. A statistically significant inverse association between total fish intake and risk of liver cancer was observed; in comparing high vs. low intake, response models indicated that this risk was reduced by 18% and 6% per one serving/week increase, respectively. Although the exact mechanism of action is unknown, it is proposed that n-3 PUFA may inhibit cancer development via molecular biosynthesis, gene transcription and expression, and signal transduction or through its anti-inflammatory effect.
Even with these findings, residual or unknown confounding factors cannot be completely ruled out and not all studies controlled for risk factors such as HBV/HCV status. While this study supports a possible relationship between fish intake and liver cancer prevention, future well-designed studies are needed.