Tuesday, May 9th, 2017
An article appearing on April 19, 2017 in PLOS ONE reports a benefit for supplementation with the omega 3 polyunsaturated fatty acid docosahexaenoic acid (DHA) in a mouse model of nonalcoholic steatohepatitis (NASH), an inflammatory liver condition that increases the risk of cirrhosis and liver cancer. Nonalcoholic steatohepatitis develops in 10% to 30% of people with nonalcoholic fatty liver disease (NAFLD), a condition that is frequently associated with metabolic syndrome, type 2 diabetes, abnormal lipids and obesity.
"Diet, genetics and lifestyle contribute to the onset and progression of NAFLD and NASH," note authors Kelli A. Lytle and colleagues. "Diets recommended for NAFLD therapy are low in fat, cholesterol and simple sugar. We have examined the effect of omega 3 polyunsaturated fatty acids in NASH therapy because omega 3 polyunsaturated fatty acids lower blood triglycerides, reduce hepatic fatty acid synthesis and inflammation, and increase triglyceride catabolism."
Acting on the findings of previous research that found a protective effect for supplementation with DHA against the development of NASH induced by a Western diet, the current study evaluated the effect of DHA in mice with pre-existing disease. Using a strain of mice that are deficient in the receptor for low-density lipoprotein cholesterol, the researchers induced metabolic syndrome and NASH characteristics by feeding them a Western diet that was moderately high in fat, simple sugars and cholesterol, and low in essential polyunsaturated fatty acids. After 22 weeks on the Western diet, a group of mice had baseline blood and liver values evaluated. The remainder of the animals were randomized to groups that received eight weeks of one of the following regimens:
- the Western diet plus olive oil
- the Western diet plus DHA
- return to low-fat, low-sucrose laboratory chow plus olive oil
- return to low-fat, low-sucrose laboratory chow plus DHA
An additional group was maintained on unsupplemented laboratory chow for the study's duration.
At the end of the 30-week study, mice that received the Western diet plus DHA experienced an increase in liver omega 3 fatty acids and no evidence of NASH progression compared to the baseline group. Animals that returned to the low-fat, low-sucrose chow diets that were supplemented with olive oil or DHA had significantly reduced markers of metabolic syndrome and NASH that were reflective of disease remission. The authors suggest that supplementing the diet with DHA could be helpful for many people with NASH, "since patient compliance to low-fat, low-sucrose dietary recommendations has historically been poor."
"Considering there are no FDA-approved ways to stop NASH progression, other than weight loss therapy, this supplement may be of significant help," stated coauthor Donald B. Jump, who is a professor at Oregon State University College of Public Health and Human Sciences. "In the time frame that we studied, DHA supplementation was not able to achieve full remission of NASH, but it did stop it from getting worse. NASH is a serious disease, an enormous health care cost and we need to put the brakes on it. There's clear evidence this might help."