We know that diet is a pillar of health. Our diets also are an important foundation of healthy sleep. Cultivating eating habits that are right for you, and support your nightly rest, is not a one-size-fits-all endeavor.
The “Mediterranean Diet,” with its abundance of unprocessed whole foods, emphasis on vegetables, fruits, moderate whole grain consumption, and healthy fat and protein sources, has been associated with higher sleep quality, including in this 2020 study of adult women in the US.
But the short- and long-term impact of foods on sleep, and sleep-quality, is actually a pretty under-researched area of sleep and nutrition science. There’s a lot more to learn about how macronutrients—proteins, fat, carbohydrates, fiber, amino acids—as well as vitamins and minerals affect sleep patterns and the quality of our nightly rest. That said, there is a growing body of scientific data that indicates what types of food can protect and enhance sleep—and what foods can undermine sleep.
Protein: Protein is a natural sleep aid. Among their benefits for sleep, protein-rich foods can be a source of tryptophan, an amino acid that the body uses to make the sleep-facilitating hormone melatonin. And consuming a larger share of calories from protein may help with nighttime satiety, keeping hunger hormones suppressed and allowing for more sustained rest overnight.
A 2020 review of recent sleep-nutrition research found that higher sleep quality is associated with consuming a greater share of daily calories from protein, and a lower share of calories from carbohydrates and fat. And a 2016 study from Columbia University found that participants who ate meals high in protein and fiber, and low in saturated fats, sugar and carbohydrates, experienced higher sleep quality and more time in deep sleep.
The broad spectrum of sleep-friendly protein sources includes eggs, fish, chicken breast, broccoli, spinach, quinoa, and almonds.
Fiber: High-fiber diets may help us achieve deeper, more restorative rest. Fiber-rich diets have been associated with less time spent in light sleep and more time spent in slow-wave sleep, the deep, highly restorative sleep stage during which the body undertakes significant cellular rejuvenation and repair. The 2016 study from Columbia University found that a single day of low-fiber dietary consumption can have a negative impact on sleep that night.
Avocadoes, pears, chickpeas, lentils, oats, and dark chocolate are among the high-fiber foods that can contribute to a sleep-promoting diet.
Magnesium: This essential mineral has powerful benefits for sleep. Magnesium calms the nervous system and relaxes muscles. It’s involved in regulating the “sleep hormone” melatonin, and in helping the body maintain healthy levels of Vitamin D, which facilitates more restful, high-quality sleep. Magnesium also maintains healthy levels of GABA, a neurotransmitter that promotes sleep. Many people lack sufficient magnesium, and low magnesium is linked to insomnia. Since magnesium isn’t produced inside the body, it’s critical we add foods to our diet that provide it.
Good dietary sources of magnesium include bananas, spinach, and avocados, brown rice, tofu, and cashews.
Potassium: Potassium promotes healthy circulation and digestion, while also helping to relax muscles, all factors that contribute to better sleep. Research has shown that elevating potassium levels (through supplementation, in this study), is linked to fewer nighttime awakenings.
Potassium-rich foods include leafy greens, potatoes, bananas, mushrooms, and legumes.
Vitamin D: Vitamin D helps to regulate the circadian clock that controls daily sleep-wake cycles and may promote longer and more restful sleep. Lack of sufficient Vitamin D has been linked to short sleep duration and to more restless sleep. Research also suggests that Vitamin D deficiency may elevate the risk for obstructive sleep apnea.
Sunlight is the very best source of Vitamin D. Our bodies produce Vitamin D in response to sun exposure. Dietary sources of Vitamin D include fatty fish, fish oil, egg yolks, dairy, and D-fortified foods.
Omega-3 fatty acids: These polyunsaturated fatty acids are what’s known as essential fats. Our bodies do not produce omega 3s, we must get them from dietary sources, which can include supplements. Research shows that omega 3 fatty acids are linked to higher sleep quality, and may help us fall asleep more quickly. Some research in animals has found that a deficiency of DHA, one of the three main types of omega-3 fatty acids, may interfere with the production of nighttime melatonin.
Many types of fish are rich sources of omega 3s DHA and EPA, including anchovies, bluefish, mackerel, wild-caught salmon, and tuna. Nuts and oils are potent sources of the omega 3 ALA, including walnuts, flax seed and flax seed oil, canola oil and soybean oil.
Water: It’s important not to overlook hydration when it comes to fueling healthy sleep. Water is a macronutrient and staying hydrated is throughout the day is important to sleeping well at night. There’s a two-way street at work here: dehydration can have a negative impact on sleep—and sleeping poorly can make us more dehydrated.
Even sleeping well, we lose about a liter of water overnight. I recommend drinking 12-16 ounces of room temperature water first thing upon waking, to help replenish overnight water loss. And hold off on caffeine for 90 minutes in the morning. Caffeine is a diuretic and drinking it immediately after waking is counterproductive to morning hydration.
What are the foods to limit in our diets, to protect our sleep?
Sugar tops this list. A sugar-laden diet creates several problems for sleep. Sugar consumption is linked to restless sleeping, and more frequent nighttime awakenings. Sugar stimulates appetite, which can lead to more late-night eating that disrupts the soundness of our rest. Sugar contributes to inflammation, and inflammation interferes with sleep. And sugar is harmful to gut health. Our gut microbiome plays a role in regulating sleep that we’re just beginning to understand, and it’s becoming increasingly clear that protecting the health of our guts can have a powerful benefit on sleep.
Saturated and trans fats. Diets higher in saturated fats have been linked to lighter sleep that’s accompanied by more frequent awakenings throughout the night. Saturated and the trans fats often found in highly processed foods are linked to weight gain and inflammation, which can undermine sleep. Fats play an important role in a healthful diet and a restful night’s sleep, but the type of fat in our diets matters a great deal.
A healthful diet is an essential contributor to the consistent quality of your sleep. Together with a healthy sleep schedule, regular exercise, and a sleep-promoting bedroom, your varied, whole-food diet can enhance your nightly rest.
This post originally appeared on The Sleep Doctor on June 17 2021. It is republished with permission.