Diet, like sleep, is one of the pillars of health and wellness. And they’re directly intertwined. Although a proper, balanced diet is essential for optimal health, poor sleep over time can undo many of the benefits of a healthy diet. It’s one of the reasons experts believe sleep is the single most effective pillar at resetting and restoring the brain and body. You may even be able to strategically harness the power of certain foods to improve sleep. On the other hand, preliminary research shows that certain foods and drinks – and the timing of their consumption – can actually wreak havoc on your sleep.
In this article, we’ll share the most recent research and science on the relationship between diet, nutrition, and sleep. By understanding how sleep and nutrition are closely linked, you can optimize your diet – both by what and when you eat – to sleep better and live healthier.
The Effects of Specific Food Types on Sleep
It’s important to remember that a balanced diet including meals not consumed too close to bedtime will likely be sufficient for maintaining healthy sleep and overall health for most people. However, recent (and still preliminary) research suggests that certain whole foods may actually improve sleep for some people.
Several studies have shown that certain tart cherries can improve both sleep duration and sleep quality in some individuals. For example, studies on people consuming the Jerte Picota cherry – a special variety native to the Jerte Valley in Spain – show that middle-aged and elderly patients showed improvements in sleep onset latency (or the time it takes to fall asleep) and total sleep time. Another study found that participants who consumed Montmorency tart cherry juice reported less time napping during the day, more total sleep time at night, and higher sleep efficiency (a ratio of time spent in bed to the total time spent sleeping). This study also found that participants had significantly elevated levels of melatonin – an important hormone responsible for circadian rhythm regulation.
Not a fan of cherries but looking for another fruit that may aid sleep? One study found that participants who consumed 2 kiwifruits 1 hour before bedtime for four weeks showed significantly improved sleep efficiency and total sleep time.
So, what’s so special about cherries and kiwis and why may they aid sleep? It turns out they’re filled with high amounts of melatonin, serotonin, and other “phytonutrients” that are thought to be important for sleep-wake regulation. However, significantly more research is needed to understand the optimal “amount” of each fruit and the best timing for when they should be consumed to support sleep.
Another potentially surprising whole food that has recently made the rounds as a sleep aid is… wait for it… oysters! That’s right – one study has shown that those slimy (glistening?) delicacies served on the half shell may actually improve sleep. In this randomized controlled trial, participants who consumed oysters rich in zinc and astaxanthin-containing krill reported an improvement in sleep quality and a reduction in the time taken to fall asleep.
There’re also some food groups that, if eaten regularly and not too close to bedtime, may also aid sleep. A recent study of more than 1,000 young adults found that women who increased their fruit and veggie intake by 3+ servings showed 2-fold higher odds of improving insomnia symptoms, a 20% increase in sleep quality, and a 4-minute reduction in the time taken to fall asleep.
Nonetheless, with so few studies and limited evidence, it’s difficult to generalize these findings outside of the laboratory. These initial results are promising though and support the idea that certain dietary habits may support not only sleep, but even subsequent health and wellness. Future research can help expand these preliminary results and should also look into other potential foods that are also known to contain high amounts of sleep-promoting properties (such as grapes!).
What About Timing?
In general, most experts agree that eating heavy meals close to bedtime interferes with the body’s process of winding down for sleep. As the body works to digest the food, your sleep can be disrupted. Studies have shown that consuming too much saturated fat and sugar right before sleep can reduce the amount of time spent in important stages of sleep, such as deep sleep. For these reasons, if you feel you must have a snack close to bedtime, remember to keep it small. Another tip is to avoid eating anything spicy close to bedtime. Ingredients such as hot sauce and hot peppers can make you feel uncomfortably warm and interfere with your sleep. Very spicy food can trigger gastric disturbances too.
How Alcohol Can Disrupt Sleep
If you’re having trouble falling asleep, it can be tempting to reach for an adult beverage. Estimates vary, but as many as 20 percent of Americans use alcohol to help them fall asleep faster. But did you know that even though alcohol can induce that sleepy feeling, it ends up interfering with sleep later in the night? The effects of alcohol last longer than you might think. For example, it takes around 5 hours for the body to eliminate alcohol after 4-5 drinks. Moderation and timing are the two key elements to minimizing the sleep-robbing effects of alcohol.
Alcohol: A Potent REM Sleep Suppressor
Drinking alcohol interferes with sleep by impairing certain stages of sleep – particularly REM sleep (the stage of sleep where dreams are most likely to occur). In fact, alcohol is one of the most potent REM sleep inhibitors. After you fall asleep and alcohol’s sedative effect fades away after the liver metabolizes alcohol, your sleep becomes disrupted, especially during the second half of the night where REM sleep is more common. For example, you’re likely to experience lighter sleep and more frequent periods of being awake. Following an evening of drinking, these wake periods may include getting out of bed to visit the bathroom, meaning even more disruption of sleep time.
Even fewer than two servings a night can significantly impair sleep. A 2018 article compared the effects of low, moderate, and high servings of alcohol on sleep quality. The authors found the following sleep quality disturbances after varying alcohol consumption:
- Low consumption: Less than 2 servings of alcohol impaired sleep quality by ~10%
- Moderate consumption: Two servings of alcohol impaired sleep quality by ~25%
- High consumption: Greater than two servings impaired sleep quality by ~40%
Alcohol and Sleep Disorders
Alcohol also increases the risk of certain sleep disorders and exacerbates the symptoms of existing sleep disorders. For example, one study found that adults who binged more than 2 days/week had 64% greater odds of insomnia than non-binge drinkers. Similar effects have been observed for young adults. Among those that reported weekly binge drinking, 56% reported trouble staying asleep, over half reported issues falling asleep, and 62% reported issues with snoring or sleep apnea. In addition to insomnia, authors of a recent systematic review found that higher levels of alcohol consumption increased the risk of obstructive sleep apnea by 25%.
To sum it up, even though it’s a common belief that drinking alcohol makes you sleep soundly, the reality is that it leads to fragmented sleep, an increased likelihood of sleep disorders, and feeling unrefreshed in the morning. And, if you had a late night, you may end up getting less sleep than you need and feeling worse in the morning for that reason too. All of this can contribute to daytime tiredness, difficulty concentrating, and problems with performance.
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