Oregon Health & Science University researchers want to know if depression, particularly among multiple sclerosis patients, is the latest illness that can be reeled in with omega-3 fatty acids found in fish.
A clinical trial is under way in the OHSU School of Medicine's Department of Neurology to determine whether omega-3 supplementation, in the form of fish oil capsules, improves the therapeutic effects of antidepressants for depression in MS patients. Depression is a common MS symptom, which affects 50 percent to 60 percent of this population.
The study is funded by the National Institutes of Health's National Center for Complementary and Alternative Medicine.
Lynne Shinto, N.D., OHSU assistant professor of neurology, is leading the randomized, double-blind, placebo-controlled trial expected to involve 60 research subjects ages 18 to 65 who have MS and suffer from mild to moderate depression. Participants are being split into two groups - one taking doses of 6 grams per day of fish oil capsules and the other taking a placebo - and will be followed for three months.
All subjects are allowed to continue taking antidepressant and MS medications while participating in the study. Those experiencing significant improvement in their depression can continue treatment for another three months so scientists can evaluate the longer-term effects of fish oil.
Shinto hopes to find out not only whether omega-3s show clinical benefits for MS depression, but also whether they reduce the levels of inflammatory agents believed to contribute to both depression and MS.
"The primary outcome is clinical. We would like to see a decrease in depression, but we also want to see if the clinical benefit is associated with a reduction of inflammatory markers," she said. "My hope is to use an agent that may be beneficial for both MS and depression. It's thinking holistically about MS depression."
Although the cause of MS is still unknown, it is believed that damage in the central nervous system results from a small group of white blood cells, which normally defend against infection in the human body, that are misdirected to attack myelin, the fatty sheath insulating nerve fibers in the brain and spinal cord. As a result, the fibers can't conduct impulses, leading to such MS symptoms as walking difficulties, memory loss, dizziness, fatigue, bladder dysfunction, vision problems, pain, imbalance, and depression. Fish-based omega-3s are believed to decrease the levels of inflammatory agents, cytokines, secreted in the blood that are involved in the demyelinization of nerve fibers.
"They're really anti-inflammatory," Shinto said of omega-3s. "Inflammation in the central nervous system is one of the causes of demyelinization, which results in MS symptoms. It is interesting that now there is a body of scientific evidence linking inflammation to depression in non-MS patients. I thought maybe the high rate of depression in MS could be related to inflammation and, in that case, omega-3 fatty acids could benefit both depression and MS."
Fish oil, particularly that of cold water fish such as salmon, mackerel, lake trout and tuna, contains high levels of two kinds of omega-3 fatty acids, eicosapentaenoic acid, or EPA, and docosahexaenoic acid, or DHA. They are believed to help improve heart health, reduce blood pressure, improve rheumatoid arthritis and lupus, and aid in cancer prevention.
Fish oil supplementation is reported to cause few side effects in subjects with depression who were on stable doses of antidepressant medication. The OHSU study will be the first to rigorously evaluate the effectiveness of a popular supplement, when taken with antidepressant, in people with MS.
Shinto is leading another OHSU study examining whether fish oil alone and a combination of fish oil and alpha lipoic acid (ALA) show benefits for people with Alzheimer's disease. The study already has shown that most subjects experience no serious side effects, after 6 months, when taking fish oil in combination with medications for dementia.
Volunteers are being recruited for the study. For more information, call the OHSU MS Center of Oregon's research line at 503 494-7963. Callers will be given an initial qualifying screening over the phone.