The association between dietary lifestyles and hepatocellular injury in Japanese workers

Elevated alanine aminotransferase (ALT) in serum, relevant to nonalcoholic fatty liver disease, has been often reported from Asian countries and the U.S., and it may be associated with lifestyle behavior. To clarify whether specific dietary behavior is associated with hepatocellular injury, we explored liver markers and dietary lifestyles (e.g., breakfast-skipping, eating for lunch, and snacking) in 1,809 male employees, aged 19-59 years, belonging to a health insurance union of automobile dealerships in Japan. ALT, γ-glutamyltransferase, and asparate aminotransferase (AST) were positively correlated with age and body mass index (BMI) (P < 0.0001). Odds ratios (ORs) of instant noodle ingestion for lunch to ALT elevation (> 30 IU/L), after adjusting for possible confounders including age, BMI, and drinking, were 1.33 (95% confidence interval, 1.01-1.75) at 1-2 times/week and 1.47 (1.07-2.01) at ≥ 3 times/week, compared to those who seldom ate instant noodles. Likewise, the OR of the ingestion at ≥ 3 times/week to γ-glutamyltransferase elevation (> 50 IU/L) was 1.42 (1.02-1.99), but the OR to elevated AST (> 30 IU/L) was not statistically significant. Habitual ethanol intake was significantly associated with hepatocellular injury, though the threshold of daily ethanol intake differed among liver markers. Despite the low OR, habitual instant noodle ingestion for lunch is associated with ALT elevation. Since the average content of saturated fatty acids in instant noodles is considerably high among cereal foods in Japan, workers with this habit should be advised to avoid having unbalanced diets.