Knit Blog

Your 9-year-old took advantage of a drop-off birthday party to help himself to an extra serving of cake after lunch. Ten hours later, he’s still wide awake, tossing in his bed and begging to watch TV. Is it the sugar in the cake that’s keeping him up all night? Or is that just a myth?

After all, on Thanksgiving Day, he fell asleep easily despite two pieces of pie - but was it the tryptophan in the turkey that counteracted the sugar to make bedtime easy?

Beliefs about foods that trigger or prevent sleep are plentiful, but research doesn’t always back them up. And while it would be nice if you could make direct correlations between food and sleep, there’s no single food that comes with a bedtime guarantee. However, there are principles that govern how diet and sleep interact, and when you understand the big picture of how nutrition helps or hurts sleep, you’ll be better able to plan meals that help your child get the rest he needs.

Nutrition and Sleep

Although there have been numerous studies around specific foods and their effect on sleep, the most compelling relationship between food and sleep is also just plain common sense: eating healthy helps you sleep better. One 2016 study found that both low carb and high carb diets had a negative impact on sleep, while the highest quality sleep occurred after a well-rounded diet of vegetables, fruits, meat and grains. Another study found that a high-sugar, high-fat diet led to poor sleep with more night wakings, while a high-fiber diet led to better sleep. The relationship between food and sleep isn’t well understood, but at the very least, good nutrition means everything in your body will function better - including your sleep patterns.

Meal Timing and the Circadian Rhythm

Eating meals at the same time every day will help bedtime, but it’s not a direct relationship. What time your child eats is one of the factors that sets his circadian rhythms. However, mealtimes themselves don’t affect what time he’ll feel sleepy; that’s set by the body’s “master clock,” a center of the brain called the suprachiasmatic nuclei, or SCN. Instead, mealtimes affect the “peripheral clocks” which are spread out throughout the body. These peripheral clocks are controlled by hormones and chemicals such as glucose. In one study, researchers found that delaying mealtimes would delay peripheral clocks without affecting the master clock, causing the circadian rhythm within the body to get out of sync. This is a common effect of jet lag, and its symptoms are similar - fatigue and irritability, and, if the asynchronicity continues long-term, possible obesity and disease. Unpredictable mealtimes, or shifting mealtimes, can have the same impact on your child as traveling across time zones, so when possible, keep mealtimes set and don’t move them much.

As long as it’s consistent, though, does it matter what time your family eats? Some studies have concluded that a large meal late in the day is unhealthy, although the research was more concerned with its effect on weight gain than its effect on sleep. But many people believe that a large, late dinner can disrupt sleep because the work of digestion can keep you awake. There isn’t a lot of research to demonstrate whether that’s true or not, but if your child suffers from GERD or acid reflux, that can be exacerbated by eating a big meal late at night. Children and adults can suffer from hidden reflux without obvious symptoms, so if your child had reflux as a baby and now struggles with sleep, it might be worth trying an earlier dinnertime to give him time to digest before bed.

Foods That Improve Sleep

So are there specific foods that improve sleep? The research is still in the early stages, but there’s evidence that indicates these foods are good choices for improving bedtime.

First, try foods with melatonin. Melatonin is the hormone that triggers the feeling of sleepiness, and its levels naturally rise as darkness falls in the evening. If you’re looking for a food to serve at bedtime to improve sleep, melatonin-rich foods are your best bet. Good choices are cherries (or even pure cherry juice, which will be digested faster) and walnuts.

Another nutrient that can help with sleep is magnesium. Magnesium helps regulate your circadian rhythms. It also binds to gamma-aminobutyric acid receptors (GABA receptors) and helps activate GABA neurotransmitters. These neurotransmitters help calm and relax the brain and muscles. Magnesium doesn’t immediately trigger sleepiness like melatonin does, but over time, having the right levels of magnesium in the body makes it easier both to fall asleep and stay asleep. Magnesium-rich foods include dark leafy greens, almonds, yogurt and black beans.

Serotonin is another neurotransmitter that can influence sleep. Its best understood role is in boosting mood, and many medications for depression help activate serotonin. But it’s also associated with regulating circadian rhythms and sleep/wake cycles. Your body creates serotonin from tryptophan, so you can increase your serotonin levels by eating foods with tryptophan, such as eggs, milk, nuts, salmon and turkey.

Another well-known snooze-inducing food is chamomile tea. Chamomile is traditionally considered a sleep aid, and the likely reason is apigenin, a flavonoid that binds to benzodiazepine receptors. This helps reduce anxiety and can cause sleepiness. Passionflower also contains apigenin, which is why many bedtime teas blend both. Chamomile tea is also naturally sweet, so your kids can enjoy it as part of your bedtime ritual, no sweeteners needed.

Finally, avoid foods that are likely to interfere with sleep. The most obvious, of course, is caffeine: the ideal amount of caffeine for kids is zero, and you should especially limit it in the afternoon and evening. Even if you never allow your kids soda or coffee, be aware of hidden caffeine in dark chocolate, and avoid that right before bed too. However, you don’t really need to worry about the sugar in the chocolate - despite the common belief that sugar causes hyperactivity, research shows that sugar’s biggest effect on sleep is actually its soporific sugar crash. Sugar, however, is unhealthy for a variety of reasons, so don’t use it to induce sleep - allow in moderation only.