From plate to pillow: how your diet influences sleep quality

Maybe you've found yourself still awake at 2 a.m. after enjoying a cup of coffee with dessert. But did you know that your food choices during the day can also affect your sleep at night?

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Increasing evidence is showing that general dietary patterns can significantly influence sleep quality and contribute to conditions like insomnia.

A significant portion of the population suffers from poor sleep quality and disorders such as insomnia and obstructive sleep apnea, a condition where the upper airways are blocked, halting breathing during sleep. Concurrently, many consume excessive amounts of fatty and processed foods, insufficient fiber, and inadequate fruits and vegetables.

While it’s challenging to establish a causal connection between these trends, growing research points to the links between sleep and diet, offering insights into the biological foundations of these relationships.

The study

Aiming to deepen the understanding of the potential link between sleep and diet in Americans aged 18 and older, researchers investigated whether adherence to dietary guidelines correlates with longer sleep duration.

Using a nationally representative dataset of surveys from 2011 to 2016, they found that individuals not consuming adequate servings of fruits, vegetables, legumes, and whole grains experienced shorter sleep durations.

In a separate study involving over 1,000 young adults aged 21 to 30, efforts to increase their daily fruit and vegetable intake resulted in reported improvements in sleep quality and reduced insomnia symptoms over three months.

Research also shows that overall healthier eating patterns are associated with better sleep quality and fewer insomnia symptoms. These include the Mediterranean diet—rich in plant foods, olive oil, and seafood, and low in red meat and added sugars—and anti-inflammatory diets, which are similar to the Mediterranean diet but place a greater emphasis on dietary components like flavonoids that lower inflammatory biomarkers in the blood.

Nutrient analysis

Within overall healthy dietary patterns, numerous individual foods and nutrients may be linked to sleep quality, with varying degrees of evidence.

For instance, consumption of fatty fish, dairy, kiwi, tart cherries, and other berries like strawberries and blueberries, has been associated with better sleep. A common pathway through which these foods may influence sleep is by providing melatonin, a key regulator of sleep-wake cycles in the brain.

Foods rich in fiber, such as beans and oatmeal, and certain protein sources, particularly those high in the amino acid tryptophan like poultry, are linked to improved sleep quality. Key nutrients that may be beneficial include magnesium, vitamin D, iron, omega-3 fatty acids, and manganese.

Foods to avoid for sleep health

Aiming for a greater intake of sleep-promoting foods is not necessarily enough for better sleep. It’s also crucial to avoid certain foods that could be detrimental, such as:

• Saturated fats, found in items like hamburgers, french fries, and processed foods, may lead to less slow-wave sleep, considered the most restorative type.
• Refined carbohydrates, present in white bread and pasta, are quickly metabolized. Consuming these foods at dinner may cause hunger-induced awakenings.
• Alcohol, while its sedative effects might initially ease falling asleep, disrupts sleep patterns by reducing the amount of REM sleep early in the night and leading to more nighttime awakenings.
• Caffeine, even when consumed six hours before bedtime, can make falling asleep difficult by blocking adenosine, a hormone that promotes sleepiness.

Excessive calorie intake can lead to weight gain, a strong predictor of obstructive sleep apnea. Excess weight can exert additional pressure on the diaphragm and lungs and may narrow the airways if fat accumulates around the neck and throat.

Interestingly, toxins in foods or packaging, like pesticides, mercury, and phthalates – chemicals used in plastic production – can affect sleep. These can be found in both healthy and unhealthy foods.

Additionally, the timing and consistency of eating, known as “chrononutrition” in sleep research, likely explain the associations between healthy diets and restful sleep.

Eating at conventional times rather than snacking randomly is associated with better sleep. Moreover, late-night eating is typically linked to unhealthy food intake—such as processed snacks—and may cause more fragmented sleep.

A fascinating piece of this puzzle is that the associations between diet and sleep often vary by gender. For example, the connections between healthy dietary patterns and insomnia symptoms may be stronger among women, potentially due to gender differences in sleep patterns, with women more likely to suffer from insomnia.

No single food or drink can magically improve sleep. It’s best to focus on overall healthy eating patterns throughout the day, with a higher calorie intake earlier. Besides avoiding caffeine, alcohol, and heavy meals in the two or three hours before bed, the last hours of the day should include other good sleep hygiene practices, like technology use reduction, decreased light exposure, and creating a comfortable and relaxing sleep environment.

Source: Annual Reviews