CONSTANTLY sleepy throughout the day? What you eat may have something to do with it, scientists say.
Researchers from Mass General Brigham linked key metabolites – molecules found in the blood that influenced by diet and hormones – to daytime drowsiness.
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One of these was tyramine, a molecule found in fermented and overripe foods, like cheddar cheese and Parmesan, salami, pickles, soy sauce, tofu and some types of beer.
It’s not the first time cheese has been linked to poor sleep – researchers from the University of Montreal recently found that dairy could bring on bad dreams.
The new study, led by investigators from Mass General Brigham and Beth Israel Deaconess Medical Center, looked into factors behing excessive daytime sleepiness (EDS) – a condition causing people to nap repeatedly during the day.
They identified seven metabolites which they said were linked to EDS.
The findings – published in Lancet eBioMedicine – suggest that excessive sleepiness is caused by internal body processes, such as hormone levels, as well as external factors such as diet.
Lead author Tariq Faquih, a postdoctoral fellow in the Division of Sleep and Circadian Disorders at Brigham and Women’s Hospital, said: “Our study suggests diet and genetics may play an important role in EDS.
“As we learn what’s happening biologically, 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.”
Researchers collected data on 877 metabolites, using blood samples from 6,000 participants.
The team also used data from a questionnaire that assessed how often people dozed off during the day.
They identified seven metabolites associated with EDS, as well as an additional three metabolites that varied by sex.
Tyramine was associated with increased daytime sleepiness, especially in men.
Meanwhile, omega-3 and omega-6 fatty acids, found in oily fish, nuts and seeds, were associated with lower risk of EDS.
According to Benenden Health, “tyramine causes the adrenal gland to release the ‘fight or flight’ hormone, which increases alertness for a number of hours”.
Foods high in tyramine include:
- Aged cheeses like cheddar, feta, blue, Swiss, Parmesan, provolone, Camembert, brie, Edam and Gruyere
- Alcohol such as draft or artisan beer or wine
- Cured meat and processed meat, such as salami, sausage, bacon, mortadella and pepperoni
- Yeast-extract spreads, such as Marmite and Vegemite
- Fermented sauces such as soy sauce, teriyaki sauce, miso, Worcestershire sauce and teriyaki sauce
- Pickled or salt-dried foods like fish
- Fermented foods such as kimchi, sauerkraut, kefir, tofu
- Dried or overripe fruits, such as raisins and overripe bananas or avocados
- Foods that have not been properly stored or are past their ‘best-before’ date
- Coffee
Researchers said their results suggest dietary changes or medications may help treat EDS.
But they noted that their study had some limitations, including difficulty in interpreting exact values of metabolites and using a sleep questionnaire instead of bringing participants into a sleep lab for tests.
The team suggested conducting a clinical trial to see if dietary changes or supplements can help reduce daytime sleepiness.
They also identified some unknown metabolites that they plan to explore further.
“Conducting 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,” Dr Faquih said.
5 other sleeping hacks
The NHS says we should all aim for seven to nine hours a night — but even the best sleepers struggle sometimes.
For most of us, a proper night’s kip feels like the ultimate prize. So how do you actually get it?
Here are some well-known hacks which might be worth a try:
1. The military hack
Used by soldiers to fall asleep in just 2 minutes, this technique involves relaxing your entire body step-by-step, starting with your face, then your shoulders, arms, and down to your legs. Clear your mind and take slow, deep breaths. It is meant to work, even if you’re lying in a noisy room.
2. The melatonin boost
Melatonin is the hormone your body makes to signal bedtime. You can help it along by dimming lights an hour before sleep and avoiding screens. In the UK, melatonin supplements aren’t sold over the counter—you need a prescription to get them.
3. Cool down to nod off
Your body needs to drop its core temperature to fall asleep easily. Which can be a bit of an issue in the summer. Keep your bedroom cool, around 18C is perfect, and use breathable bedding. Cooler temps help you drift off faster and get deeper sleep.
4. Cut caffeine after midday
That afternoon cuppa might keep you wired when you should be winding down. At least eight hours should pass between your last hit of caffeine and bedtime. Try switching to decaf or herbal teas after lunch to avoid a late-night buzz.
5. Breathe and relax
Try slow, deep breathing or a quick meditation before bed. It calms your mind and body, making it easier to switch off and drift off.
