Fish oil has been used for many years to relieve the symptoms of inflammatory diseases such as rheumatoid arthritis; however, its beneficial effects do not always apply to everyone. Now new research shows genetics may play a role in whether or not fish oil may help those with severe inflammation.
The research team, led by Professor Bob Grimble at the University of Southampton Institute of Human Nutrition, is investigating the reasons for this variability in the effectiveness of fish oil, and are studying the genes that influence the ability of the body to make a molecule called tumor necrosis factor-alpha (TNF). Their findings are published in the August edition of the American Journal of Clinical Nutrition.
“This molecule acts as a trigger for inflammation and has been linked with the severity of inflammatory disease,” explains Professor Grimble. “Fish oil may act as an anti-inflammatory substance by suppressing the body’s ability to make TNF.”
The team studied the effects of a daily dose of fish oil on TNF production in a group of 250 healthy young men. They compared the genetic make-up of men in whom fish oil decreased the ability to make TNF with that of men in whom it did not.
“We were surprised to find that although variations in the gene carrying the code for making TNF had no influence on the anti-inflammatory effects of fish oil on TNF
production, variations in a gene lying next to the TNF gene did indicate which men showed decreased TNF production after taking fish oil,” Grimble said.
Intriguingly the same gene that indicates a possible anti-inflammatory response to fish oil also carries the code for making a molecule called lymphotoxin-a, which influences immune function. Raised TNF production is associated with variations in this gene.
The Biotechnology and Biological Sciences Research Council (BBSRC), which funded the research, is funding further studies by the team to examine how the genetic characteristics of people with inflammatory diseases can influence the ability of fish oil and vitamin E to act as anti-inflammatory nutrients.
They will look at the effects of fish oil in people with severe cardiovascular disease and the effects of vitamin E in those with rheumatoid arthritis.
“We hope eventually that we will be able to predict those who will most benefit from an increased intake of foods rich in nutrients with ‘anti-inflammatory’ properties,” added Grimble.