Author information
1 Faculty of Health Sciences, The University of Sydney, Lidcombe, NSW 2141, Australia. h.parker@sydney.edu.au.
2 Charles Perkins Centre, The University of Sydney, Camperdown, NSW 2006, Australia. h.parker@sydney.edu.au.
3 Nutrition & Metabolism Group, The Heart Research Institute, Newtown, NSW 2042, Australia. cohnj@hri.org.au.
4 Faculty of Health Sciences, The University of Sydney, Lidcombe, NSW 2141, Australia. helen.oconnor@sydney.edu.au.
5 Charles Perkins Centre, The University of Sydney, Camperdown, NSW 2006, Australia. helen.oconnor@sydney.edu.au.
6 School of Biomedical Sciences & Pharmacy, Faculty of Health and Medicine, University of Newcastle, Callaghan, NSW 2308, Australia. manohar.garg@newcastle.edu.au.
7 Boden Institute of Obesity, Nutrition, Exercise and Eating Disorders, The University of Sydney, Camperdown, NSW 2006, Australia. ian.caterson@sydney.edu.au.
8 Storr Liver Centre, The Westmead Institute for Medical Research, The University of Sydney, Westmead, NSW 2145, Australia. jacob.george@sydney.edu.au.
9 Faculty of Health Sciences, The University of Sydney, Lidcombe, NSW 2141, Australia. nathan.johnson@sydney.edu.au.
10 Charles Perkins Centre, The University of Sydney, Camperdown, NSW 2006, Australia. nathan.johnson@sydney.edu.au.
11 Boden Institute of Obesity, Nutrition, Exercise and Eating Disorders, The University of Sydney, Camperdown, NSW 2006, Australia. nathan.johnson@sydney.edu.au.
Abstract
Being overweight increases the risk of the development of metabolic conditions such as non-alcoholic fatty liver disease (NAFLD), which is itself an independent predictor of cardiovascular disease. Omega-3 polyunsaturated fatty acid (PUFA) supplementation is recommended for prevention of chronic disease, and is thought to reduce raised liver fat, yet there have been few randomized controlled trials with accurate measurement of liver fat. We assessed the effect of 12 weeks of supplementation with omega-3 PUFA from fish oil versus placebo on quantified liver fat, liver tests, and body composition including visceral adipose tissue (VAT) in a double-blind randomized controlled trial. Fifty apparently healthy overweight men (BMI 25.0?29.9 kg/m²; waist > 94 cm) were randomly allocated to consume fish oil (total daily dose: 1728 mg marine triglycerides, of which 588 mg EPA and 412 mg DHA, combined with 200 mg antioxidant, coenzyme Q10) or placebo (olive oil capsules) daily for 12 weeks. Liverfat was assessed using proton magnetic resonance spectroscopy. All outcomes were assessed at baseline and following 6 and 12 weeks of supplementation. Baseline liver fat was 4.6 ± 0.5% (range: 0.6 to 18.2%); 16 (32%) participants met the criteria for NAFLD (>5.5% liver fat). Repeated measures ANOVA revealed no significant time or group × time effect for fish oil versus placebo for liver fat, liver enzymes, anthropometry, or body composition including VAT (p > 0.05 for all), with similar finding for sub-analysis of participants with NAFLD. Omega-3 PUFA did not appear to be an effective agent for reducing liver fat in overweight men. The factors determining the health benefits of omega-3 PUFA supplementation on an individual level need to be clarified.