Trouble sleeping? The culprit may be something you ate

How does food influence sleep?

It's a cycle," says Dr Marie-Pierre St-Onge, an associate professor of nutritional medicine in the division of general medicine at Columbia University in New York City, USA. "How you sleep at night influences what you eat during the day, and what you eat during the day influences how you sleep at night."

Average sleep duration has been shrinking over the past several decades, alongside the rise in obesity and diabetes. This led St-Onge and her colleagues to investigate how diet and meal composition might be affecting sleep. They were particularly interested in the role carbohydrates - which affect blood glucose levels - might play.

Eating carbohydrates makes blood glucose, or blood sugar, rise. But how much and how fast differs by the type of carbohydrate.

Foods low on the glycaemic index include many that promote cardiovascular health. These include:

• Certain fruits such as apples and oranges.

• Vegetables.

• Minimally processed grains such as barley and quinoa.

• Beans.

• Low-fat dairy.

• Nuts.

In a 2020 study in the American Journal of Clinical Nutrition¹, St-Onge and her colleagues showed eating a high glycaemic index diet could increase the likelihood of insomnia in postmenopausal women. A 2020 analysis of 24 studies in the Journal of Human Nutrition and Dietetics² found sleeping 5.5 hours or less per night was linked to eating more food overall, with a higher intake of the macronutrients - fat, protein and, carbohydrates - that together make up total calorie consumption.

St-Onge, author of "Eat Better, Sleep Better," says it's likely because not getting enough sleep can alter the brain's response to food. Some of her earlier work, including a 2012 study in the journal Sleep³, found that shorter sleep duration influenced hormone production and did so differently for men and women. Among men, getting less sleep increased levels of ghrelin, the hormone that controls hunger. Among women, it altered levels of GLP-1, reducing satiety, meaning women felt less full after eating.

What foods should you eat if you want to sleep better?

You should eat a healthy diet throughout the day to have healthy sleep at night," St-Onge says. "Legumes and whole grains are particularly good at being protective against sleep disorders."

Studies show adherence to the Mediterranean-style eating pattern, associated with better cardiovascular health, can also be good for better sleep.

A 2018 study⁴ in Sleep found people who stuck to a Mediterranean diet were less likely to have insomnia and more likely to get adequate sleep. A 2020 study⁵ in the journal Nutrients that looked at diet and sleep among women found better adherence to the Mediterranean diet - especially fruits, vegetables and legumes - was linked to better sleep quality or fewer sleep disturbances.

"Relatively speaking, the same foods that are good for metabolic health are good for promoting good sleep," says Dr Maya Vadiveloo, an associate professor in the department of nutrition at the University of Rhode Island College of Health Sciences in Kingston, USA.

Of course, diet isn't the only factor affecting sleep, says Vadiveloo. "There are a lot of reasons people have trouble sleeping."

Stress, a noisy environment, not getting enough physical activity during the day and exposure to light from devices such as mobile phones, laptops and tablets are among the factors that can disrupt sleep, she says.

Other diet-related factors, such as eating too late at night or consuming spicy or citric foods that increase acid reflux, can also disrupt sleep, Vadiveloo says.

"Any type of discomfort is going to disrupt your sleep." But those factors differ from person to person, she says. "It's not a one-size-fits-all approach."

Suggestions for better sleep

Vadiveloo suggests keeping a food-and-mood log to help people identify what works and what doesn't to improve the quality and quantity of their sleep.

"Notice the connections between when you feel stressed and what you ate," she says. "What did you eat on nights you felt well rested? What about when it took a long time to fall asleep, or you woke up a lot during the night? Track this over time and notice the patterns."

This article is published with kind permission of the American Heart Association, which has been striving to save and improve lives for more than 100 years.

References

1. Gangwisch et al: High glycemic index and glycemic load diets as risk factors for insomnia: analyses from the Women’s Health Initiative

2. Fenton et al: The influence of sleep health on dietary intake: a systematic review and meta-analysis of intervention studies

3. St-Onge et al: Short Sleep Duration, Glucose Dysregulation and Hormonal Regulation of Appetite in Men and Women

4. Castro-Diehl at al: Mediterranean diet pattern and sleep duration and insomnia symptoms in the Multi-Ethnic Study of Atherosclerosis

5. Zuraikat et al: A Mediterranean Dietary Pattern Predicts Better Sleep Quality in US Women from the American Heart Association Go Red for Women Strategically Focused Research Network

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