Long Oral Presentation Nutrition Society of Australia 50th Annual Scientific Meeting 2026

Dietary omega-3 and omega-6 fatty acids and metabolic dysfunction-associated steatotic liver disease: Does diet quality matter? (147098)

Ayesha Sualeheen 1 , Ashleigh Habkouk 2 , Welma Stonehouse 1 , Tommy HT Wong 1 , Sze-Yen Tan 1 , Ekavi N Georgousopoulou 2 3 , Elena S George 1
  1. Institute for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Geelong, VIC, Australia
  2. School of Medicine Sydney, University of Notre Dame Australia, Sydney, NSW, Australia
  3. Discipline of Nutrition and Dietetics, Faculty of Health, University of Canberra, Canberra, NSW, Australia

Metabolic dysfunction-associated steatotic liver disease (MASLD), the most common liver disease affects over 1.3 billion people globally (1). Poor diet quality is a major modifiable risk factor, with the Mediterranean diet recommended for MASLD management, partly due to its favourable polyunsaturated fatty acid (PUFA) profile, including greater omega-3 intake (2, 3). However, associations between the dietary omega-6 to omega-3 (n-6: n-3) ratio, individual PUFAs and MASLD remain underexplored. This study examined associations between dietary n-6: n-3 ratio and individual PUFAs with MASLD and whether these differed according to overall diet quality in a large U.S. adult population. Seven NHANES cycles (2005–2018) were included with adults aged ≥18 years who had reliable two-day dietary recalls and who met criteria for MASLD using the Fatty Liver Index (4). Diet quality was assessed using the Healthy Eating Index-2020 (HEI-2020) (5). Associations between PUFA intakes and MASLD were assessed using binary logistic regression. Non-linearity was assessed using restricted cubic splines. Analyses were adjusted for age, sex, ethnicity, income-to-poverty ratio, diabetes and cardiovascular disease history, physical activity, smoking, total energy intake and NHANES survey cycle. PUFAs showing significant interactions with HEI-2020 (P-interaction<0.05) were further examined after stratification by the median HEI-2020 score. In adjusted analyses, docosahexaenoic acid (DHA) was associated with lower odds of MASLD (OR 0.75, 95% CI 0.57–0.99), while significant nonlinear associations were observed for the n-6: n-3 ratio and marine-derived omega-3 (eicosapentaenoic acid [EPA], docosapentaenoic acid [DPA] and DHA). Compared with the median n-6: n-3 ratio of 9.0, a ratio of 5.7 was associated with 16% lower odds of MASLD (OR 0.84, 95% CI 0.76–0.94). Marine-derived omega-3 showed a nonlinear association (P-overall=0.001; P-nonlinearity<0.001), with odds initially increasing from the median intake of 0.06 g/day, peaking at 0.10–0.12 g/day, and subsequently declining to 14% lower odds at 0.50 g/day (OR 0.86, 95% CI 0.77–0.97). Significant interactions with HEI-2020 were observed for total omega-3, alpha-linolenic acid (ALA), EPA, total omega-6, linoleic acid (LA) and arachidonic acid (AA) (all P-interaction<0.05). When stratified by the median HEI-2020 score (53.4), total omega-6 and AA were associated with higher odds of MASLD below the median. Above the median, EPA was associated with lower odds of MASLD, while total omega-6 and LA showed U-shaped associations. For AA, the odds of MASLD increased from approximately 0.12 g/day and plateaued at 0.25 g/day. In conclusion, in this nationally representative cohort of U.S. adults, associations between dietary PUFAs and MASLD were nonlinear and varied by overall diet quality. A lower n-6: n-3 ratio and higher marine-derived omega-3 intake were associated with lower odds of MASLD. These findings reinforce the importance of overall diet quality and highlight marine-derived omega-3-rich foods as a potential dietary strategy for MASLD management.

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