A fatty acid abundant in fish oil could yield a new medication for the treatment of epilepsy, a new study suggests, after finding that it reduced seizures in mouse models.
What is more, researchers found that the compound, called docosahexaenoic acid (DHA), led to an increase in estrogen in brains of the mice, suggesting that DHA and estrogen work together to suppress seizures.
Study co-author Yasuhiro Ishihara, of the Laboratory of Molecular Brain Science at Hiroshima University in Japan, and colleagues recently reported their findings in the journal Scientific Reports.
Epilepsy is a neurological disorder characterized by spontaneous, recurrent seizures, which are triggered by a surge in electrical signaling between brain cells, or neurons.
According to the Centers for Disease Control and Prevention (CDC), around 3 million adults and 470,000 children in the United States are living with active epilepsy.
There are medications available that can help patients to control their seizures, and these are effective for around 7 in 10 people with epilepsy.
It is a general consensus that estrogen - which is a hormone best known for its role in sexual and reproductive development - can worsen seizures in people with epilepsy. However, some studies have shown that the hormone may actually have the opposite effect.
Previous research has also indicated that epileptic seizures could be reduced with DHA, an omega-3 fatty acid present in fatty fish - such as salmon, herring, and mackerel - and fish oil supplements.
Given that both estrogen and DHA have shown potential for seizure suppression, Ishihara and colleagues set out to determine whether there might be a link between the two.
DHA supplementation delayed seizures
The researchers came to their findings by testing three oil-based diets on three groups of mice for 28 days. One group was fed a diet a rich in soybean oil, one received a diet rich in cottonseed oil, and one group was fed a diet rich in cottonseed oil plus DHA supplementation.
The researchers explain that these three diets were selected due to the different amounts of DHA produced in response - for example, the body produces less DHA in response to cottonseed oil than soybean oil.
After the 28 days, each group of mice was given seizure-inducing drugs. The researchers found that the occurrence of seizures was delayed for much longer in mice fed the soybean oil diet, compared with the diet rich in cottonseed oil only. Also, when seizures did strike, mice fed the soybean oil diet had them for a shorter duration.
Mice fed the cottonseed oil diet supplemented with DHA, however, fared best. It took significantly longer for seizures to arise in this group, compared with the other diet groups.
This finding, the team says, confirms that dietary DHA plays a role in preventing seizures.
Confirming the role of estrogen
Next, the team assessed the estrogen levels in the brains of each diet group. They found that brain estrogen levels in mice fed the soybean oil diet were twice as high as those in mice fed the diet rich in cottonseed oil only.
Interestingly, however, mice fed the cottonseed oil diet supplemented with DHA had higher brain estrogen levels than mice fed the soybean oil diet.
From these findings, the researchers speculated that DHA affects the production of estrogen in the brain, which, in turn, influences seizure development.
The team confirmed this theory in another experiment, in which they fed mice either cottonseed oil only, cottonseed oil and DHA supplements, or a combination of cottonseed oil, DHA supplements, plus an estrogen-suppressing drug called Letrozole. Each group was then given seizure-inducing drugs.
The researchers found that the mice given cottonseed oil, DHA, and Letrozole experienced seizures significantly faster than mice that were only fed cottonseed oil and DHA, highlighting the role of estrogen in seizure prevention.
Based on their results, Ishihara and colleagues suggest that DHA supplementation could help to prevent seizures in people with epilepsy.