Daily low-dose fish oil capsules reduced seizure frequency by 33.6% in patients with drug-resistant epilepsy in a single-center, randomized, phase II trial.
The report was published Sept. 8 in the Journal of Neurology, Neurosurgery, and Psychiatry.
The magnitude of this effect was similar to that seen in many studies of antiepileptic drugs. Moreover, low-dose fish oil may also yield cardiovascular benefits in this patient population, "a finding of some importance given the recent data that the risk of death due to myocardial infarction is significantly higher in people with epilepsy" than in the general population, said Dr. Christopher M. DeGiorgio of the department of neurology at the University of California, Los Angeles, and his associates.
The n-3 fatty acids in fish oil are thought to modify calcium and sodium channels in the brain, reducing membrane excitability in neurons. So far, the results of studies of high-dose fish oil as a treatment for epilepsy have been "promising yet inconclusive." This double-blind, crossover trial compared low-dose and high-dose fish oil and placebo in 25 adults with a mean age of 33 years. At baseline, they had three or more localization-related partial onset or generalized tonic/clonic seizures per month and had failed to respond to at least three antiepileptic drugs.
Each oral gel capsule contained either 216 mg of eicosapentaenoic acid (EPA) and 144 mg of docosahexaenoic acid (DHA), for a total of 360 mg of n-3 fatty acids, or a matching placebo capsule filled with corn oil. All study patients took three fish oil capsules per day (low-dose period), three fish oil capsules twice a day (high-dose period), or placebo capsules (control period) for 10 weeks, with 6-week washout periods between each course, for a total study length of 42 weeks.
The primary endpoint, the average seizure frequency, was 12.18 per month during low-dose fish oil therapy, compared with 17.67 seizures per month for high-dose fish oil and 18.34 seizures per month for placebo. This represents a reduction of 33.6% in seizure frequency with low-dose fish oil. In addition, 5 of 20 patients (25%) showed a 50% reduction in seizures only while taking low-dose fish oil, and 2 of 20 (10%) were free of seizures only while taking low-dose fish oil, Dr. DeGiorgio and his associates said (J. Neurol. Neurosurg. Psychiatry 2014 Sept. 8 [doi:10.1136/jnnp-2014-307749]).
The fish oil capsules proved to be safe, with no serious adverse events occurring during the study. One patient died from autopsy-confirmed sudden death in epilepsy during treatment with high-dose fish oil, but the death was deemed unrelated to fish oil.
It is not yet understood why the low-dose treatment produced better results than the high-dose treatment, the researchers noted.
These findings warrant confirmation in a large, multicenter trial. And it remains to be seen whether this beneficial effect is sustained over time, since the treatment period in this trial was only 10 weeks.
This study was supported by grants from the National Center for Complementary and Alternative Medicine, UCLA’s General Clinical Research Center, and individual donations. Marijo Clark and Pharmavite provided the fish oil and placebo capsules. Dr. DeGiorgio reported no conflicts of interest. An associate disclosed part-time employment with NeuroSigma, which develops devices for epilepsy and other disorders.