Fish Oil Disappoints as MS Therapy

Vitamin D may be the answer

/ Author:  / Reviewed by: Joseph V. Madia, MD

Multiple sclerosis is a chronic central nervous system disease with no cure, only treatments. Researchers have fervently worked to come up with new therapies to treat the condition.

In addition to searching for areas of the body to target for new medications and working to develop new drugs, they also are considering more holistic supplements in hopes that they may find a new method for helping MS patients better manage the disease.

The idea that omega-3 fatty acids, commonly referred to as fish oil, though they can derive from plants and other sources, could benefit MS patients had been batted around because fish oil has the potential to reduce inflammation.

In theory, Øivind Torkildsen, MD, PhD, of Haukeland University Hospital in Norway, theorized that the essential fatty acids could provide anti-inflammatory and neuroprotective effects in multiple sclerosis. Unfortunately, it wasn't meant to be.

Though omega-3 fatty acids may provide benefits for certain other medical conditions, researchers ultimately concluded that fish oil did not reduce MS disease activity in a study of patients with relapsing-remitting multiple sclerosis published recently in Archives of Neurology, a Journal of the American Medical Association Network publication.

However, the research did open another avenue, suggesting that vitamin D instead may reduce symptoms and improve the quality of life for MS patients.

Breaking down MS

Multiple sclerosis affects about 2.5 million patients worldwide. In the simplest terms it is an autoimmune disease that affects the brain and spinal cord.

It's more common in women and affects individuals at any age, though it is most commonly diagnosed when patients are between the ages of 20 and 40.

According to the National Institutes of Health the cause of MS is damage to the myelin sheath, the protective covering that surrounds nerve cells, which causes nerve signals to slow or stop. That nerve damage stems from inflammation that occurs when the body's own immune cells attack the nervous system.

However, what causes this to happen is not known. Scientists have suggested that it could be caused by a virus or a gene defect, or environmental factors could have an influence.

Patients tend to have periods with few or no symptoms followed by attacks where symptoms worsen. The actual symptoms are wide and varied, and may be different for each patient.

Some common symptoms include muscle spasms and loss of balance, difficulty walking, tremors, weakness or coordination problems, numbness, tingling or pain; and eye symptoms. Symptoms also often affect the brain and speech, and may cause difficulty reasoning, memory loss, dizziness, hearing loss, slurred speech or difficulty chewing and swallowing.

The trial

During the double-blind placebo-controlled trial, Dr. Torkildsen and a team of researchers examined whether omega-3 fatty acids might benefit 92 MS patients by reducing disease activity either as a therapy on its own or in conjunction with injected interferon beta-1a. Patients included in the study had relapsing-remitting MS, meaning that their symptoms come and go.

Half of the patients were assigned to take 1350 milligrams of eicosapentaenoic acid and 850 milligrams of docosahexaenoic acid daily, while the rest took a placebo. Six months after the trial began, investigators added interferon beta 1a three times a week for the following 18 months for all patients.

Interferon beta is injected directly into the muscle, and is used to decrease the number of episodes of symptoms and slow disability development in patients with relapsing-remitting MS. It has been shown to aid MS patients with chronic progressive forms of the disease, though symptoms might not always be present. The drug is in a class of medications called immunomodulators, though how it works to treat MS is not known.

MRI imaging was used to measure disease activity. In measuring the activity, researchers looked at the number of new T1-weighted gadolinium-enhancing lesions in the brain.

The MRI image shows active lesions where there has been a breakdown of the blood-brain barrier, and where inflammation is present.

Gadolinium refers to a chemical compound used as a contrast agent given during MRI scans that highlights areas of inflammation. Lesions enhanced by the contrast are considered new because they will only be enhanced with gadolinium for six weeks or less. This allows doctors to determine which lesions are new so that they can determine whether there is recent disease activity suggesting a relapse.

They found that the fish oil group had an average of three new T1-weighted gadolinium-enhancing lesions compared to two in the placebo group during the first six months. They didn't find any differences between the two groups in the number of relapses reported during the first six months or at the end of 24 months. They also did not observe differences between the two groups in fatigue or quality of life scores.

"Yes, we were surprised," admitted Dr. Torkildsen. "Based on pre-clinical findings, we had expected to find a positive effect of omega-3 supplementation. This demonstrates how important it is to perform controlled studies."

Vitamin D instead?

Though the findings were disappointing for researchers, and also for MS patients, the research did not suggest that omega-3 fatty acid supplements were harmful. They also were not found to interfere with interferon beta treatment. So while there may not be a benefit, patients won't be negatively affected if they elect to take fish oil supplements anyway.

Prior to the study, many patients had tried fish oil supplements on their own, often in addition to other treatments, hoping it would aid with disease management.

Though the recent study did not find a benefit, two previous studies had suggested that omega-3 fatty acids may reduce MS disease activity, and additional research will be needed to clarify whether fish oil could have a role in treating MS.

"It has been estimated that about one third of all MS patients are using or have tried supplementation with omega-3 to control disease progression in MS, and neurologists have traditionally recommended omega-3 supplementation to their MS patients," noted Dr. Torkildsen.

"Preliminary studies have suggested a protective effect of omega-3 supplementation in MS. Although this is the most commonly used and recommended complementary treatment for MS, there have not been any randomized controlled studies to document if omega-3 actually has an effect on MS-disease activity."

Dr. Torkildsen noted that the pair of studies that found omega-3 fatty acids to be beneficial to MS patients also included other dietary advice, such as decreasing the intake of saturated fat or eating more fish.

He said the positive results found in previous trials could possibly have been as a result of vitamin D, which appears to be a promising candidate. Randomized controlled trials are currently underway to assess whether vitamin D might be the real source of disease activity reduction for MS patients.

"We found no serious adverse events with the omega-3 supplementation, and it is possible that omega-3 could have other beneficial effects," Dr. Torkildsen said. "Our main message is that there is no evidence for a positive effect of omega-3 supplementation on the disease course of MS. Many sources of omega-3, however, also contain vitamin D, and there is a growing evidence that vitamin D supplementation could have a positive effect on MS disease activity."

Review Date: 
April 26, 2012