By Cara Michelle Miller
If you’re clocking eight hours of sleep but still reaching for that third cup of coffee by noon, the problem might not be in your bedroom—it could be in your veins.
A large recent study published in Lancet eBioMedicine found that people with higher levels of certain blood molecules—including omega-6 fatty acids, which are found mostly in nuts, seeds, and plant oils—were significantly less likely to experience excessive daytime sleepiness, or EDS.
EDS affects about 1 in 3 Americans and is known to raise the risk for conditions like high blood pressure, heart disease, and diabetes. While insomnia and sleep apnea are common culprits, this research suggests that how your body metabolizes food, hormones, and stress may also contribute to feeling overly tired during the day.
“We are beginning to understand how and why EDS occurs, the early signs that someone might have it, and what we can do to help patients,” said lead researcher Tariq Faquih, a postdoctoral fellow at Brigham and Women’s Hospital, in a press release.
What’s Going On in Your Blood?
Researchers found that people who had more of seven specific blood metabolites were more alert during the day.
They analyzed blood samples from more than 6,000 adults with an average age of 48, measured levels of metabolites, and compared them to participants’ reported sleepiness.
One of the strongest links to less daytime sleepiness was with omega-6 fatty acids. These fats, already known to support heart and brain health, also help the body produce melatonin—the hormone that promotes sleep—making it easier to be alert after a good night’s sleep. Research has indicated that eating more omega-3 and omega-6 fatty acids may help people fall asleep faster.
Another molecule found at higher levels in more alert people was sphingomyelin—a type of fat found in nearly every cell, especially in the nervous system. It plays an important role in hormone signaling and may help regulate the body’s internal clock, which controls sleep-wake cycles. The body can produce sphingomyelin on its own, but it also comes from certain foods such as eggs and dairy, which can increase its levels.
Small Changes, Real Effects
The improvements weren’t dramatic, but they were meaningful.
For every standard increase in these beneficial metabolites, participants scored about a third to half a point better on the widely used tool called the Epworth Sleepiness Scale, or ESS, which measures the likelihood of dozing off in daily situations like reading or riding in a car.
The ESS ranges from 0 to 24. A score of 11 or higher is considered excessive, and about 15 percent of participants met that threshold.
“A 2-point change in ESS is what is typically thought to be clinically significant,” said study supervisor Dr. Susan Redline, a professor of sleep medicine at Harvard Medical School, in an email to The Epoch Times.
“Individuals with moderate daytime sleepiness have reported that it does affect their daily functioning to varying degrees,” Faquih told The Epoch Times in an email.
Sex Differences Emerge
The associations between blood metabolites and sleepiness were stronger in men.
For instance, in men, higher levels of tyramine O-sulphate—a compound formed from the breakdown of foods such as aged cheeses and cured meats—were associated with more daytime sleepiness. This compound was also associated with lower sleep quality and delayed sleep timing, likely because the chemical can disrupt pathways involved in sleep, such as melatonin pathways.
In women, the connections were less pronounced. Researchers suggest hormone fluctuations related to the menstrual cycle, pregnancy, or menopause can mask these relationships.
However, in larger European studies used to confirm the results, women with higher levels of omega-6, as well as omega-3 fatty acids—which are found in fatty fish such as salmon and in nuts and oils—were also less likely to report daytime sleepiness, suggesting that healthy fats matter for both sexes.
What’s Next–Can Diet Help Treat EDS?
The researchers believe that their findings could eventually lead to new ways of treating chronic fatigue—especially approaches focused on nutrition, supplements, or medications that target these key metabolic pathways.
Today, treatments for daytime sleepiness work by stimulating the brain to help people feel more awake, using prescription medications or therapies for sleep apnea, such as continuous positive airway pressure, or CPAP machines. These options work by increasing certain “wake-up” chemicals in the brain, but they don’t focus on improving nutrition or the body’s metabolism.
“Our study suggests diet and genetics may play an important role in EDS,” Faquih said, though he noted that more research is needed to test whether deliberately boosting these metabolite levels can reduce sleepiness in real-world settings.
However, they also acknowledge limits. Measuring metabolites isn’t simple, and relying on self-reported sleepiness rather than clinical sleep studies leaves some gaps, according to the study authors.
The next step is clinical trials that could reveal exactly how much dietary changes might influence daily energy levels.
“Conducting a clinical trial would be a big next step and could help us understand how much these metabolites and their effect sizes influence EDS,” Faquih said in an email.
