Mounting interest in nutritional interventions which might improve the quality or duration of sleep has become one of the leading driving forces behind dietary supplement innovation over the past several years, as poor sleep quality reaches epidemic proportions. Currently, an estimated 50 million-plus Americans suffer from dozens of sleep disorders. Some preliminary research into the role that omega-3s play in sleep quality and duration has been conducted, and a recent clinical trial published in the journal Nutrients accounted for possible differences in the way that each respective omega-3 fatty acid found in fish oil, EPA and DHA, could have on sleep impact.
 
“EPA and DHA are incorporated into the membranes of cells throughout the body, and DHA is particularly enriched in the brain,” the authors said. “As such, adequate intake of these important fatty acids ensures proper functioning across multiple systems. Indeed, low levels of circulating n-3 PUFAs were observed in a wide range of psychopathologies, including attention deficit hyperactivity disorder, major depression, and Alzheimer’s disease. Converging evidence suggests n-3 PUFAs are also important for sleep.”
 
The study enrolled 84 participants between 25 and 49 years old, who were considered to be healthy, and who had habitually consumed low amounts of oily fish. Over the span of 26 weeks, participants were administered an oil rich in either EPA or DHA, with a placebo group being observed as well.
 
During the trial, participants were required to wear a sleep monitor, provide urine samples at baseline and at 26 weeks, and record their sleep outcomes in a sleep diary which measured changes in subjective sleep following intervention. For all three of the groups, compliance was reported to be very good.
 
EPA and DHA’s Differentiators
Following an analysis of the results, the researchers concluded that DHA-rich oil resulted in a significant increase in sleep efficiency, as well as a decrease in sleep latency (the time it takes to fall asleep). Despite these improvements in objective actigraphy sleep measures in the DHA-rich group, the group reported subjectively feeling less rested than the placebo group – they also said they were less energetic and ready to perform than the EPA-rich group. Lastly, the DHA-rich group seemed to have a reduced sleep fragmentation index than the placebo. “However, the latter effect was found to only be evident during the second night of the seven nights recorded, and must be interpreted with caution,” the researchers said.
 
The authors cited a previously-held theory that DHA’s role in supporting the transformation of serotonin into melatonin likely has a role in modulating the transition between sleep and wakefulness. The negative subjective ratings, which ran contrary to the objective measurements of sleep quality, could not be explained, however, the authors noted that there are many gaps within insomnia research, and not much is understood about the discrepancy between sleep performance and subjective reporting on sleep quality (which often has poor estimates from participants).
 
The EPA-rich oil also had a number of significant improvements to sleep quality that were different than the DHA-rich oil in this trial. The group had a significant increase in sleep efficiency compared to the placebo, and, compared to the DHA group, the EPA group had a significant decrease in total time in bed and total sleep time. The authors identified EPA’s unique role as a sleep-supporter by inhibiting the formation of E2-series prostaglandins, which in turn inhibits the release of serotonin, a neurotransmitter associated with wakefulness.
 
“It should be noted that although participants in the EPA-rich oil group reported the shortest sleep times, this did not appear to lead to any reduction in the quality of sleep,” the authors wrote. “In fact, a trend towards sleep efficiency, compared to placebo, was observed along with no increases in the time spent awake, number of awakenings, or decreased ratings of subjective sleep quality. This might potentially suggest that EPA is beneficial for regulating a healthy sleep cycle and could help protect against suboptimal sleep, which is known to be detrimental for health.”