Groundbreaking research reveals seven mysterious molecules in your blood linked to daytime drowsiness, and your diet might hold the key to staying awake.
Do you ever feel like you could fall asleep at any moment, no matter how much rest you get at night? You’re not alone. Millions of people struggle with daytime fatigue, but new research may finally explain what’s happening inside your body. Scientists have uncovered clues in your bloodstream that could answer why you feel so tired during the day.
The hidden epidemic of daytime sleepiness
About one in three Americans battles the urge to nap throughout the day. This isn’t just a result of staying up too late. Excessive daytime sleepiness, often called EDS, is linked to higher risks of heart disease, obesity, and diabetes. Until recently, experts weren’t sure what caused some people to feel so drained during daylight hours.
Researchers from Mass General Brigham took a closer look. They analyzed blood samples from 6,000 adults and identified seven molecules that are connected to EDS. Surprisingly, some of these molecules are influenced by what you eat.
- More than 877 blood metabolites were studied across a diverse group of people
- The findings were confirmed in three separate international studies
- Sleepiness was measured using real-life situations, not just laboratory tests
How your diet affects your energy levels
What you eat could have a bigger impact on your energy than you think. Two types of molecules stood out in the study as especially important.
The helpful nutrients
Omega-3 and omega-6 fatty acids, found in foods like fish and nuts, were linked to lower levels of daytime sleepiness. People with higher amounts of these nutrients in their blood tended to feel more alert. According to lead researcher Dr. Tariq Faquih, “This suggests Mediterranean-style diets might be protective.”
Foods that may increase sleepiness
On the other hand, tyramine, a compound found in fermented foods such as aged cheese and overripe bananas, was linked to increased drowsiness. The effect was especially noticeable in men, who felt more tired after meals high in tyramine. If you’ve ever felt sluggish after eating certain foods, this could help explain why.
The role of hormones in daytime sleepiness
Your hormones may also play a big part in how awake or tired you feel during the day. The study found that sex hormones can influence sleep cycles and energy levels.
- Progesterone, which is higher in women, was connected to melatonin production
- Three additional blood molecules behaved differently in men compared to women
- Hormone imbalances might explain why some people struggle with sleepiness even after a full night’s rest
These findings could lead to new ways to manage tiredness. Instead of relying on caffeine or energy drinks, future treatments might include personalized diets or supplements based on your unique blood chemistry.
What’s next in the fight against fatigue
Scientists are already planning their next steps to better understand and treat daytime sleepiness. Their future work could transform how we manage and prevent fatigue.
- Clinical trials will test if omega-3 supplements can help reduce EDS
- Researchers are exploring additional unknown molecules found in the blood
- Blood tests may one day help identify people at risk for excessive daytime sleepiness before symptoms start
Dr. Faquih explained, “A clinical trial would be a big next step and could help us understand if omega-3s and omega-6s obtained from diet could help lower risk of EDS.”
There are still some challenges. The study relied on people’s self-reported feelings of sleepiness rather than laboratory sleep tests, and some of the blood molecules are still not fully understood. Even so, these results could be the breakthrough many people need to finally get to the bottom of their constant fatigue.
Simple steps you can take right now
While more research is on the way, there are some things you can try today to help boost your energy levels and reduce daytime sleepiness.
- Choose fish, nuts, and seeds instead of processed snacks to add more omega-3 and omega-6 fatty acids to your diet
- Limit fermented foods if you notice they make you feel more tired
- Talk to your doctor about checking your hormone levels if you’re often sleepy during the day
The answer to your daytime tiredness might be simpler than you think. Paying attention to what you eat and how your body responds could make a real difference. As scientists continue to unlock the mysteries of sleepiness, small changes in your daily habits could help you feel more alert and energized.
Source: Brigham and Women’s Hospital. “Seven blood molecules that could explain why you’re always sleepy.” ScienceDaily. ScienceDaily, 8 September 2025. <www.sciencedaily.com