Fish oil can lower high triglycerides and also appears to help lower your risk for heart disease, but it may not do much if you suffer from liver disease, according to National Institutes of Health online medical encyclopedia Medline Plus. Fish oil is potentially valuable for a host of health conditions because it contains the omega-3 fatty acids eicosapentaenoic acid, or EPA, and docosahexaenoic acid, or DHA. Consult your doctor if you have a fatty liver, however, because while it is theoretically beneficial in some cases, it may worsen your condition under other circumstances.
Nonalcoholic Fatty Liver Disease
A 2011 “Clinical Nutrition” study concluded that fish oil may provide benefits if you have nonalcoholic fatty liver disease, the most common cause of liver disease in the United States. Fish oil appears to reduce further development of a fatty liver, according to the study. However, additional clinical trials are needed before fish oil can be recommended for use in nonalcoholic fatty liver disease, or NASH. The study is significant because as of 2011 no therapies exist for NASH. Recommendations include losing excess weight, exercising more, following a balanced diet, avoiding unnecessary medicines and avoiding alcohol, according to the National Digestive Diseases Information Clearinghouse.
A dosage of 1 g of fish oil daily may be enough to improve nonalcoholic fatty liver disease, according to “The Real Vitamin and Mineral Book” by certified nutrition specialist and fellow of the American College of Nutrition Shari Lieberman and Nancy Pauling Bruning, who holds a master's degree in public health. Animal studies show that omega-3 fatty acids can reduce scarring in the liver, reduce markers of liver inflammation and improve insulin sensitivity – results that have been confirmed by limited clinical trials with humans, according to a 2010 scientific review in “Alimentary Pharmacology and Therapeutics.” However, the human trials had design flaws, so more research is needed before effectiveness can be confirmed and factors such as dosage can be set, according to the authors of the review. Also, fish oil may not provide a benefit in all cases of NASH. A 2007 “Hepatology” study found that effects on the liver differ depending on the cause of the fatty liver. In mice, fish oil prevents fatty liver induced by sucrose but worsens safflower oil-induced fatty liver.
Alcoholic Liver Disease
If you have alcoholic liver disease using fish oil may worsen your condition, according to a 1998 study published in “Hepatology.” That’s because it appears to increase lipid, or fat, peroxidation and to hamper antioxidant function. This leads to more liver damage when alcoholic liver disease is present. Lipid peroxidation is an indication of oxidative stress in tissues or cells. There appears to be a link between unsaturated fat in general and the severity of liver scarring in alcoholic liver disease, according to “Fatty Liver Disease” by Geoffrey C. Farrell, director of the Storr Liver Unit at the University of Sydney’s Westmead Hospital in Australia, and Jacob George, head of clinical hepatology at the Storr Liver Unit. Fish oil has a high percentage of polyunsaturated fatty acids and is extremely susceptible to lipid peroxidation. In cases of alcoholic liver disease, consuming more peroxidable fatty acids appears to lead to greater liver injury, note Farrell and George.
If you are interested in using fish oil, consult a doctor first – especially if you have a health condition or take medicine. While fish oil is considered safe for most people when recommended dosages are followed, taking high doses is potentially dangerous because it can keep your blood from clotting, raising your risk for bleeding. This is a concern if you have liver disease, according to National Institutes of Health online medical encyclopedia Medline Plus. High doses also may reduce your immune system function, according to Medline Plus. Fish oil also can make it harder to control blood sugar if you are diabetic, worsen symptoms of depression or bipolar disorder and cause your blood pressure to drop too low if you take blood pressure medications. It interacts with other medicines as well, including blood thinners and birth-control pills.
- Medline Plus; Fish Oil; February 2011
- National Digestive Diseases Information Clearinghouse: Nonalcoholic Steatohepatitis
- “Clinical Nutrition”; The Therapeutic Potential of Long-Chain Omega-3 Fatty Acids in Nonalcoholic Fatty Liver Disease; H. Shapiro, et al.; 2011
- “Hepatology”; Increased Lipid Peroxidation and Impaired Antioxidant Enzyme Function is Associated with Pathological Liver Injury in Experimental Alcoholic Liver Disease in Rats Fed Diets High in Corn Oil and Fish Oil; R. Polavarapu, et al.; 1998
- "Hepatology”; Fish Oil Prevents Sucrose-Induced Fatty Liver but Exacerbates High-Safflower Oil-Induced Fatty Liver in DDY Mice; T. Yamazaki, et al.; 2007