Did your mom ever suggest a warm glass of milk to help you sleep?
Science says she may be right.
An emerging field of research called chrononutrition indicates that choosing the right foods and meal times may improve our sleep. Some key findings: Eat dinner early. Keep consistent schedules. And, yes, drink milk.
You already know that fruits, veggies and lean protein are good for your health. But they can boost your sleep, too. These foods are the basis for the Mediterranean diet, which research shows may improve sleep quality, reduce sleep disturbances and boost sleep efficiency—the amount of time you spend asleep when you are in bed.
Eating a Mediterranean or other similarly healthy diet is linked to a reduction in symptoms of insomnia, according to a just-published review of 37 studies with almost 600,000 participants. This same research also found that unhealthy diets—high in simple carbohydrates and processed foods—are associated with an increase in insomnia symptoms, says Frank Scheer, a professor at Harvard Medical School, who studies the internal body clock.
When we eat affects our internal body clock, or circadian system, which regulates our physiology and behavior, including sleep. While our master clock resides in our brain, each of our organs has its own clock, too. We don’t want to wake up our stomach just when we’re trying to go to sleep.
“There’s a rhythm to our digestive system,” says Kelly Baron, director of the behavioral sleep medicine program at the University of Utah. “And eating at the wrong time can cause internal jet lag.”
Roughly a third of American adults don’t get the recommended seven to nine hours of sleep, according to the Centers for Disease Control and Prevention.
When Sarah Linderman, 46, started having sleep problems several years ago—tossing and turning for hours before drifting off, then popping awake for good at 3 a.m.—a doctor suggested she focus on her diet.
The doctor recommended she consume more of her calories earlier in the day, load up on protein and veggies, cut back on cocktails at night and finish her last meal at least three hours before bedtime. Linderman soon found herself falling asleep more easily. She also began sleeping seven or eight hours uninterrupted and waking feeling refreshed in the morning.
“With the right nutrition, I took my sleep back,” says Linderman, who owns a marketing company in San Pedro, Calif.
What’s the best way to adjust your diet to improve your sleep? Here’s some advice, according to a growing body of research.
Follow a Mediterranean diet
A diet high in vegetables, fruits, whole grains, fish and unprocessed lean meat is good for nutrition and may promote sleep by reducing inflammation and providing nutrients that boost the neurotransmitter serotonin and the hormone melatonin. It also balances our gut microbiome, which may help regulate our circadian rhythm, says Uma Naidoo, a nutritional psychiatrist and director of nutritional, lifestyle and metabolic psychiatry at Boston’s Massachusetts General Hospital.
Some nutrients are particularly helpful.
Tryptophan is an amino acid necessary to produce melatonin. Our bodies can’t produce tryptophan, but foods that provide it include turkey, chickpeas, milk, grains, nuts and seeds.
Serotonin is also a precursor to melatonin. Fruits, vegetables and nuts can help boost serotonin.
Melatonin promotes sleep and influences the timing of the circadian system. Eggs, fatty fish such as salmon, mushrooms, bananas and tart cherries help promote it.
Naidoo’s perfect sleep-promoting dinner suggestion? A mushroom omelet with a side salad topped with flaxseed and walnuts.
Have an early dinner
People who eat close to bedtime have poorer sleep quality, studies show.
Researchers think this may have something to do, in part, with body temperature. Our body typically cools down before bed; this is an important part of our circadian rhythm. Digestion heats our body up, messing with this process.
“Your stomach is working up a sweat just as you’re trying to wind down,” says Marie-Pierre St-Onge, director of the Center of Excellence for Sleep and Circadian Research at Columbia University.
Eating before bed can also cause acid reflux, which often disrupts sleep.
A good rule of thumb, researchers say: Eat dinner at least two to three hours before bedtime to give yourself time to digest your meal.
Be consistent about meal times
Having a regular eating rhythm sends a strong signal to your brain about when it is time to be alert and when it is time to be drowsy, says the University of Utah’s Baron.
Try to eat your first meal and your last meal around the same time each day. “This bookends your day and helps differentiate between waking activities and nighttime,” Baron says.
Eat breakfast
When we don’t eat breakfast, we tend to get hungrier at night. And that sets us up for making poorer food choices closer to bedtime, says St-Onge.
Some studies have shown that people who skip breakfast have lower sleep quality. Researchers aren’t sure why, but they believe it’s because people who eat breakfast tend to practice other healthy habits, such as being more active.
Cut back on alcohol
Yes, alcohol may help you wind down at night and fall asleep faster. But it also messes with your sleep quality. (Do I really need to tell you this?) It suppresses REM sleep, causes sleep disturbances and shortens sleep duration, says Massachusetts General’s Naidoo.
A light evening snack is OK
Hunger is stimulating because the hormones that make you seek food are the same ones that arouse you from sleep, says Columbia’s St-Onge. It’s hard to fall asleep when you’re obsessing about the ice cream in your freezer.
If you eat a snack, make it light and have it at least an hour or so before bed. Pair protein and healthy carbohydrates—hummus and pita or fruit and yogurt—for the biggest sleep boost. Protein is satiating and carbohydrates promote sleepiness by helping the absorption of tryptophan.
And, yes, milk can help, too. A study of people recovering from a cardiovascular event showed that they slept better if they drank milk with honey before bed. And, in general, people who consume more milk throughout the day have better sleep, research shows. Milk is a good source of tryptophan, St-Onge says.
So go ahead and listen to your mom. Have that glass of milk.
(An article from the Wall Street Journal. June 2024)