MONDAY, April 16 (HealthDay News) -- Omega-3 fatty acid supplements don't appear to have any benefit on multiple sclerosis (MS), according a study by Norwegian researchers.

Multiple sclerosis affects about 2.5 million people worldwide. Some prior research has indicated that omega-3 fatty acid supplements might have anti-inflammatory effects that could benefit those with the disease, according to background information in the study.

Omega-3 fatty acids are found in cold-water fish, such as salmon, and in fish oil supplements.

"Our study provides evidence that omega-3 supplementation has no beneficial effect on MS, neither given alone nor in combination with interferon treatment," said lead researcher Dr. Oivind Torkildsen, from Haukeland University Hospital, in Bergen. Interferon is a standard drug given to MS patients.

"Our data do not suggest that omega-3 fatty acid supplementation was harmful or that it interfered with interferon beta treatment," he added.

This study is important, not only for neurologists and MS patients, but also for general practitioners, who frequently advise patients about lifestyle interventions and complementary approaches to MS treatment, Torkildsen said.

The report was published in the April 16 online edition of the Archives of Neurology.

For the study, Torkildsen's team looked at 92 MS patients, aged 18 to 55, with a form of the disease known as relapsing-remitting multiple sclerosis.

Half of the patients were given the supplement alone or the supplement plus injections of interferon beta-1a. The other half received an inactive placebo.

After six months, all patients were given interferon beta-1a three times a week for an additional 18 months.

When the patients underwent MRI brain scans to look for new lesions, the researchers found no effect on the disease among those taking omega-3 fatty acid supplements.

The results were the same whether omega-3 fatty acid supplements were used alone or in combination with interferon beta-1a, the study authors noted.

These findings were in contrast with two other studies that showed possible positive effects from fish oil supplements, Torkildsen and colleagues pointed out.

No difference existed between the groups in the number of relapses during the first six months of treatment or after 24 months, and there were no differences in fatigue or quality of life, according to the results.

Commenting on the study, Dr. Kottil Rammohan, a professor of neurology and director of the MS division at the University of Miami Miller School of Medicine, said, "It doesn't surprise me that omega-3 fatty acids had no effect on MS. I have never looked upon omega-3 fatty acids as having an effect on MS and I have a lot of patients who take these supplements for heart health," he said.

However, Rammohan added, "This study won't change my advice to patients to take omega-3 fatty acid supplements because they have other health benefits."

More information

For more information on MS, visit the National Multiple Sclerosis Society.