Writing in the Journal of Biological Chemistry, scientists at the Georgia Institute of Technology (Georgia Tech) and the University of Illinois at Urbana-Champaign outlined the evidence that prompted their research. Earlier epidemiological studies have linked the consumption of omega-3 fatty acid to improvements in diseases including multiple sclerosis but lacked insights into the mechanism of action.

Other studies suggested that omega-3 fatty acids such as docosahexaenoic acid (DHA) are converted into metabolites that directly modulate immune responses, leading the Georgia Tech and Illinois researchers to focus on docosahexaenoyl ethanolamide (DHEA). DHEA is synthesized from DHA in the brain and is found at lower levels in people with neuroinflammation.

Building on those findings, the researchers showed that DHEA affects Th1 and Th17 cells in vitro. The helper T cells are implicated in autoimmune diseases, including multiple sclerosis. A mouse model of multiple sclerosis shed further light on the potential role of DHEA by showing that the molecule is found at its highest concentration when the animals are in remission.

To show if DHEA can improve outcomes, the researchers gave daily doses of the molecule to mice. The study found DHEA delayed the onset of disease, the rate of relapse, and the severity of clinical scores at relapse. Increased time to relapse correlated to a reduction in the infiltration of Th1 cells in the central nervous system, suggesting dietary changes may be able to help multiple sclerosis patients manage their symptoms.

Aditi Das, an associate professor of chemistry and biochemistry at Georgia Tech, outlined the findings and their implications for the management of autoimmune diseases including multiple sclerosis in a statement.

"Our goal was to use something that is naturally found in food and the human body to see if we can enhance it to reduce the disease severity in multiple sclerosis patients," Das said. "We believe our findings could lead to the discovery of new solutions to aid in managing symptoms of multiple sclerosis and other chronic inflammatory diseases like diabetes."

The researchers said that more work is needed to show how DHEA affects other parts of the immune system and how it performs in humans, but they are optimistic that the study points to a way to reduce inflammation. An earlier study of 312 patients found fish oil rich in omega-3 fatty acids had no significant effect on disability progression and relapses, although the National Multiple Sclerosis Society said that there are "some hints of effectiveness" and "reasonable doses" are safe to take.