Plant‐based and animal‐based low‐carbohydrate diets and risk of hepatocellular carcinoma among US men and women

Little is known about the role of low-carbohydrate diets (LCDs) in the development of hepatocellular carcinoma (HCC). We prospectively evaluated the associations between plant-based and animal-based LCDs and risk of HCC in the Nurses’ Health Study (NHS) and the Health Professionals Follow-up Study (HPFS). Dietary intake was assessed every 4 years using validated food frequency questionnaires. Cox proportional hazards regression models were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs). HRs are shown for a 1-standard deviation (SD) increment with variable modelled as continuous. During 3,664,769 person years of follow-up, there were 156 incident HCC cases. Although there were no associations between overall or animal-based LCD score and risk of HCC, plant-based LCD score was inversely associated with HCC risk (HR: 0.83; 95% CI: 0.70-0.98; Ptrend =0.03). Carbohydrate intake, especially from refined grains (HR: 1.18; 95% CI: 1.00-1.39; Ptrend =0.04) was positively, while plant fat (HR: 0.78; 95% CI: 0.65-0.95; Ptrend =0.01) was inversely associated with HCC risk. Substituting 5% of energy from plant fat and protein for carbohydrate (HR: 0.74; 95% CI: 0.58-0.93; Ptrend =0.01) or refined grains (HR: 0.70; 95% CI: 0.55-0.90; Ptrend =0.006) was associated with lower HCC risk. In conclusion, a plant-based LCD and dietary restriction of carbohydrate from refined grains were associated with a lower risk of HCC. Substituting plant fat and protein for carbohydrate, particularly refined grains, may decrease HCC incidence. Our findings support a potential benefit in emphasizing plant sources of fat and protein in the diet for HCC primary prevention. Additional studies that carefully consider hepatitis B and C virus infections and chronic liver diseases are needed to confirm our findings.