But there’s a solution that’s often overlooked, and it may be sitting right there in your kitchen: the right foods.
Just as diet can have an effect on the systems in the brain and body that control blood pressure, blood cholesterol, weight and other aspects of health, it can affect the processes that regulate sleep.
“We’re finding more evidence that improving your diet can lead to better sleep,” says Marie-Pierre St-Onge, director of the Center of Excellence for Sleep and Circadian Research at Columbia University Irving Medical Center in New York. “All of the research is pointing toward similar findings: The foods and dietary patterns that are associated with better sleep tend to be lower in glycemic index [meaning they have less effect on blood sugar levels]low in saturated fat, low in added sugars and high in fiber.”
The reverse is equally true. Foods with the opposite attributes can get in the way of a good night’s sleep.
When you build your diet around foods that fit those criteria, you end up with something that looks like the Mediterranean diet — a way of eating that emphasizes plant-based foods, including lots of fruits, vegetables, legumes, whole grains and healthy sources of fat (such as olive oil, nuts and avocados), while limiting red meat, sweets and refined carbohydrates (such as foods made with white flour). Studies examining the relationship between this pattern of eating and better sleep have shown promising results.
For example, a 2020 study published in the journal Nutrients followed more than 400 US women for a year to see whether compliance with the Mediterranean diet affected their sleep quality. Those with the greatest adherence to this way of eating had 30 percent lower sleep disturbance scores (meaning they got more solid rest) than those with the lowest adherence.
Certain categories of foods — fruits, vegetables and legumes — stood out for their positive effects on various measures of sleep quality. “Legume consumption was associated with overall better sleep,” says Brooke Aggarwal, an assistant professor of medical sciences at Columbia University Medical Center in New York, and one of the study authors. “And the effects were dose-dependent — the more servings of legumes they ate, the more significant improvement they had in sleep efficiency.” (Sleep efficiency is the ratio of how many hours you sleep to how many hours you spend in bed.)
But it’s not that the Mediterranean diet necessarily has magic abilities to enhance sleep. “It’s the healthy components of that way of eating — more fruits and vegetables, legumes, whole grains, and healthy fats,” St-Onge says. “You can focus on eating those foods in any predominantly plant-based diet.”
The advantages of better eating
There are several possible explanations for how a healthy plant-based diet enhances sleep.
“All of the foods plentiful in the Mediterranean diet are rich sources of fiber, which has beneficial effects on the gut microbiome,” Aggarwal says. A healthier gut and better sleep are connected by various mechanisms. “The gut and brain communicate via the gut-brain axis,” she says. “Specific to sleep, the gut microbiome is thought to send signals that help regulate circadian rhythms.”
Circadian rhythms, part of the body’s internal clock, are controlled by daylight and darkness and affect many body processes, including hormonal activity and the sleep-wake cycle. Additionally, the gut is involved in the synthesis of serotonin, a neurotransmitter that promotes a better mood and is an important component for regulating sleep.
Higher fruit and vegetable consumption as part of a plant-based diet also means greater intake of beneficial antioxidant compounds called polyphenols. Emerging research points to an association between these compounds and improvements in sleep. “Polyphenols have an effect on the autonomic nervous system and can increase heart rate variability [the fluctuation in time between heartbeats],” St-Onge says. Higher heart rate variability is a sign you’re in a relaxed state and is associated with better sleep quality, she says. Some polyphenols also act on receptors in the brain that promote sleep.
Plant foods can enhance the production of the sleep hormone melatonin. Legumes, soy, leafy greens and seeds are all rich sources of tryptophan, an amino acid (a building block of protein) that the body uses to make melatonin. Turkey and dairy are often cited as the best sources of tryptophan. But the tryptophan in those high-protein foods isn’t actually synthesized as efficiently in the brain as the tryptophan from plant foods. That may be part of it because you also need B vitamins and carbohydrates to process tryptophan — both of which you get when you eat a diet rich in fruits, vegetables, legumes and whole grains.
Eating habits that can wreck your sleep
In addition to leaving you feeling tired, not getting enough sleep affects various processes in your brain and body that can lead to unhealthy food choices. Sleeping too few hours may increase hormones that stimulate appetite as well as suppress those that signal satiety. At the same time, short sleep duration appears to activate the reward centers in the brain — increasing cravings for high-sugar, high-fat snack foods.
“If you have good sleep, you tend to make better choices in all aspects of your life — eating healthier foods, taking the stairs instead of the elevator,” St-Onge says. “And when you don’t have good sleep, you tend to go for the easier, less healthy choices — more processed foods, more snacks, more sugar, less exercise. And this vicious cycle perpetuates itself.”
A habitually unhealthy eating pattern (that may be exacerbated by not sleeping well) can in turn lead to more sleepless nights.
Along with obvious sleep-breakers like alcohol and caffeine, foods that are high in fat, sugar and saturated fat have been shown to hurt sleep quality. For example, a small study led by St-Onge, published in the Journal of Clinical Sleep Medicine in 2016, found that when participants ate more sugar, refined carbs and saturated fat, it took them longer to fall asleep and they spent less time in the deep, restorative short wave sleep phase.
Over the years, there have been various studies of how eating individual foods could ease you into slumber. These studies were typically small in scale (and often funded by the food industry), but they usually resulted in lots of splashy headlines touting the miraculous effect of certain foods — such as tart cherries or kiwis. But experts caution against looking at a single food as nature’s sleeping pill.
“I like to advocate for better overall dietary patterns for better health and better sleep,” St-Onge says. “Including those foods can’t hurt, but you can’t negate the effect of a day’s worth of a bad diet with a single kiwi before bed.”
Copyright 2022, Consumer Reports Inc.
Consumer Reports is an independent, not-for-profit organization that works side by side with consumers to create a fairer, safer and healthier world. CR does not endorse products or services, and does not accept advertising. Read more at ConsumerReports.org.