Does what you eat affect how you sleep, or how you sleep affect what you eat?

Source: Healthing/ image: GETTY/Author: Daniel Neuman

Researchers aren't quite sure how exactly sleep is connected to diet, but one thing we know for sure is that the two are deeply connected.

One dietary strategy that has been tied to quality sleep is the Mediterranean diet. GETTY

It’s not a secret that sleep is important to everything that has to do with our health — from strengthening our immune system and contributing to our energy levels to helping with muscle-building and supporting cognitive ability. But how can we ensure we are getting the amount of quality of sleep our bodies need to maintain all of these important functions?

One way is by understanding the connection between what we eat and our sleep patterns, a link that researchers have been investigating: does diet affects sleep, or sleep affect diet, or both?

What do circadian rhythms and hormones have to do with diet?

Our sleep cycle is regulated by circadian rhythms — a natural internal process that regulates our sleep and wake cycle. Circadian rhythms operate on 24-hour cycles and are regulated by genes, light-dark cycles, as well as hormones.

Melatonin is a key hormone produced in response to darkness, and it may encourage both sleep onset and sleep quality . Tryptophan is a precursor for melatonin, and an essential amino acid, meaning it must be obtained from food, such as milk, canned tuna, turkey, chicken, oats, cheese, nuts, bread, chocolate and fruits. While melatonin generally can be taken safely as a supplement to help with sleep, it should not be a long-term strategy. Speak with your doctor before supplementing to ensure safety.

Two other hormones affected by sleep are involved in regulating appetite. Ghrelin is a hormone that increases appetite — it’s sometimes called the ‘hunger hormone’ — while leptin is an appetite suppressant hormone. A 2020 study found that short periods of sleep is associated with increases in ghrelin, and not only contributes to sleep deprivation, but can also affect your food choices during the day. On the other hand, getting adequate sleep may help control your appetite hormones, which in turn may affect your energy and daily caloric intake.

The Mediterranean diet may be a good choice for good sleep

One dietary strategy that has been tied to quality sleep is the Mediterranean diet which is high in vegetables, fruits, whole grains, beans, lentils, nuts and seeds, olive oil, and seafood. According to research , a Mediterranean diet may be associated with less change in sleep duration and better sleep quality in older adults. Similarly, a  randomized control trial from 2016 concluded that diets high in fibre and lower in saturated fat predicted a better quality of sleep. In contrast, diets lower in fibre, and higher in saturated fat and sugar are associated with lighter, less restorative sleep with more periods of wakefulness during the night.

In fact, research published in 2021 found that of the 29 studies reviewed, the high consumption of processed and free-sugar rich foods was associated with worse sleep quality, whereas a whole food diet was linked to better sleep quality. However, the study was unable to determine a causal relationship, warranting the need for future studies.

Alcohol and caffeine affects sleep

While drinking caffeine daily can improve alertness, it has also been shown to be associated with disturbed sleep and daytime sleepiness. Similarly, alcohol may improve your ability to fall asleep faster , however acute and chronic alcohol consumption are associated with lower quality sleep in several stages of the sleep cycle. Overall, if you are looking to get better sleep, you may want to consider decreasing the amount of caffeine and alcohol you drink each day, or cut them out of your diet entirely.

Magnesium and cherries are good choices for good sleep

Magnesium has been linked to quality sleep , and is a nutrient often low in people’s diets. While taking a magnesium supplement may increase the length of time you sleep, how well you sleep as well as increase melatonin and decrease insomnia, there are also many foods that contain this important mineral, including nuts and seeds (particularly pumpkin, chia, and hemp seeds), as well as dark green leafy vegetables, legumes, and whole grain cereals.

Certain types of cherries may also increase melatonin in the urine as well as boosting total sleep time and quality — likely because of the high concentration of melatonin in cherries, as well as the high levels of antioxidants.  Kiwi fruit has also been shown to improve sleep. One four-week study in adults with sleep problems found that two kiwifruits per day one hour before bedtime significantly increased sleep quantity and quality, potentially due to the fruit’s unusually high content of serotonin, folate, and high antioxidant capacity.

While researchers continue to study the exact relationship between diet and sleep — whether diet affects sleep, or sleep affects diet — we know for certain that the two are deeply connected. While a healthy pattern of eating, such as the Mediterranean diet, seems to improve sleep, getting enough sleep also plays a role in the hormonal regulation of hunger and satiety.

Perhaps a good starting point for all of us in our quest for better sleep is to consider our diets and how often we feel that we have gotten a solid rest during the night — it may take just a few small changes to get you on the road to better zzz’s, a shift that will greatly benefit your overall health.