Omega-3-Rich Fish, Supplements Linked to Lower MS Risk

Damian McNamara

April 18, 2018

Eating fish and seafood rich in omega-3 polyunsaturated fatty acids at least once a week or one to three times a month combined with taking daily fish oil supplements may lower the risk for multiple sclerosis (MS), new research shows.

Investigators note the findings add new confidence that omega-3s may be behind this observed protective effect in MS.

Researchers studied 1153 patients with newly diagnosed MS or its precursor, clinically isolated syndrome (CIS), and matched controls from the MS Sunshine Study.

They found a 45% reduced risk for MS or CIS among those with high fish intake and daily use of fish oil supplements compared with participants who ate fish less than once a month on average and who did not take supplements (odds ratio [OR], 0.55; P = .0002).

"Most previous studies asked about fish and/or seafood, but we also asked about fish oil supplement use," Annette Langer-Gould, MD, PhD, Kaiser Permanente Southern California in Pasadena, told Medscape Medical News.

The research will be presented April 26 at the upcoming American Academy of Neurology (AAN) 2018 Annual Meeting in Los Angeles, California.

Greater Confidence

Another unique feature of the study is that the investigators looked at genetics. They measured single-nucleotide polymorphisms (SNPs) in the fatty acid desaturase (FADS) gene cluster that modulate fatty acid levels. Although these genes have been associated with cognition, cardiovascular disease, and inflammation, their association with MS was unknown.

Two SNPs, rs174611 and rs174618, in FADS2 emerged as independently associated with a lower risk for MS, even after accounting for high fish intake (adjusted ORs, 0.66 and 0.64, respectively; P = .007).

The findings provide "more confidence" that the omega-3s are providing the observed benefit vs a "substitution effect," Langer-Gould said.

In other words, people eating salmon, shrimp, canned tuna, or sardines three times or more a month likely saw benefit from the omega-3s, and not just because they were substituting fish for other, less healthy meals.

"We found that fish/seafood/fish oil consumption is protective, and we really do think it's through omega-3 fatty acids," she said.

The study also reports an association between higher fish consumption and risk for MS and is not suggesting a causal relationship.

"The way I use this kind of data in clinic is when patients ask, 'How do I lower the risk of my children getting MS?' I would add this to the list," Langer-Gould said.

She educates patients that not smoking is the strongest protective factor, but getting exercise and vitamin D outdoors and eating a diet rich in omega-3 fatty acids are recommended.

"When patients ask about their own diet, I would say we don't know for sure," Langer-Gould said. She tells patients that "two chronic diseases are worse than one, and you already have one, so let's do everything we can to prevent you from getting cardiovascular disease or diabetes."

The number one source of omega-3 fatty acids is fish consumption, but people who are vegan, vegetarian, or allergic or have a fish aversion can get precursors from plant-based sources, she said.

The plant sources can "then be synthesized into the polyunsaturated fatty acids we actually find circulating in our bloodstream and in our tissue."

She added that that is the function of the genes explored in the study.

A total of 180 of patients with MS had high fish intake compared with 251 of the healthy controls. Study participants had an average age of 36 years.

The investigators are working on reproducing and validating the genetic findings by using a different dataset.

Clinical Implications Unclear

Commenting on the findings for Medscape Medical News, Nicholas LaRocca, PhD, vice president, health care delivery and policy research, National MS Society, said that while the study shows an association it does not establish cause and effect, so the clinical implications for MS are uncertain.

"At this time, it is not possible to recommend these dietary elements as preventive of MS," LaRocca said. "However there are other health benefits associated with them related to comorbidities that affect people with MS, and so they could be one part of a healthy lifestyle."

The National Institute of Neurological Disorders and Stroke provided funding for the study. Langer-Gould and LaRocca have disclosed no relevant financial relationships.

American Academy of Neurology (AAN) 2018 Annual Meeting. Abstract  1826. To be presented April 26, 2018.

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