Dietary n-6 to n-3 fatty acid ratio is related to liver fat content independent of genetic effects: Evidence from the monozygotic co-twin control design.

Background & Aim: Lifestyle changes focusing on diet and exercise remain the cornerstone of the treatment of non-alcoholic fatty liver disease (NAFLD). The present co-twin control study of monozygotic (MZ) twin pairs was designed to identify nutritional factors potentially involved in the pathogenesis of NAFLD.
Methods: Cross-sectional study of 50 MZ twin pairs (age range: 23-36 years), of which ten pairs were discordant for liver fat (liver fat percentage of one twin ≤5% and his/her co-twin >5% and a difference between co-twins of >5%) as determined by magnetic resonance spectroscopy. Nutrient intake was calculated from 3-day food records.
Results: Among the ten liver fat-discordant twin pairs, the n-6: n-3 ratio was significantly higher in the twins with higher liver as compared to their co-twins with lower liver fat (6.6:1 vs. 3.2:1, p-value = 0.005). In multiple regression analysis of within-pair differences including all 50 twin pairs, a higher n-6: n-3 ratio was significantly associated with a higher liver fat percentage within MZ twin pairs after adjustment for body mass index, energy intake and other covariates (standardized beta = 0.43, p-value = 0.001).
Conclusions: Our findings suggest that the n-6: n-3 ratio is a promising dietary agent for the prevention and treatment of NAFLD. Clinical trials are required to better understand causal relationships and required doses.
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