How Food Affects Sleep (and Vice Versa)
Science is very clear: poor sleep can lead to a variety of health problems, including changes in eating habits. For example, people who sleep less than seven hours are more likely to choose unhealthy, high-calorie foods. Moreover, a person who does not get enough sleep eats more than usual because their body has lower levels of the satiety hormone leptin.
And a group of Australian scientists also claim that food, in turn, affects the quality of sleep. Researchers published an article in the Lancet journal, in which they claim that carbonated drinks and fast food increase stress levels and disrupt sleep.
As a result, a person can get into a vicious circle: due to lack of sleep, he begins to eat poorly, and a bad diet disrupts the work of the internal clock – this is the name of one of the parts of the hypothalamus, responsible for ensuring that a person is awake during the day and sleeps at night.
What exactly is happening? To help a person fall asleep, the hypothalamus must receive melatonin closer to nightfall – it is produced in the pineal gland of the brain (epiphysis) when darkness sets in, and also enters the body with certain foods (we will tell you which ones a little later). The task of melatonin is to make sure that the hypothalamus does not react to the invigorating signals of other neurohormones, which are produced, for example, when light hits our eyelids or during stress.
So when we eat unhealthy foods, our body becomes stressed, which prevents the brain from producing melatonin, and because of this, we experience problems with sleep.
Foods That Improve Sleep
Food is not only a source of energy, but also chemicals needed for good sleep. If you eat one of the products from the list below for breakfast, lunch, and dinner, then by the time you fall asleep, your body will have tryptophan, the “raw material” for creating melatonin.
It is important to remember two more points:
- For a good night’s sleep, it is important not to overload the gastrointestinal tract, that is, not to overeat. Therefore, it is traditionally believed that the last meal should be at least two hours before bedtime.
- But hunger can also ruin your sleep. So if you missed a full dinner, you can have a snack with something that contains “ready-made” melatonin.
Let’s take a closer look at these products.
Eggs
Those who cook scrambled eggs or toast for breakfast create a good foundation for sleep. Eggs are protein, and protein is amino acids, including the tryptophan we need. According to the World Health Organization, the recommended dietary intake of tryptophan is 4 mg per kilogram of weight. Thus, a person weighing 70 kg should consume about 280 mg of tryptophan per day. One large chicken egg provides 77 mg of tryptophan, which is 27% of the daily requirement for the amino acid.
Cherry juice
Cherry juice contains procyanidin B2, a substance that helps tryptophan survive. Scientists from Louisiana (USA) studied the effect of sour cherries on sleep. A total of 11 young people participated in the study, who were divided into 2 groups. One group drank two glasses (240 ml) of natural cherry juice per day for two weeks – one in the morning, the other before bed. And the second group was given a drink with cherry flavoring and sweetener instead of juice. The results of the study confirmed that cherry juice increases the duration and quality of sleep.
Berries
Sweet berries contain melatonin and elements that are good for sleep. This is the conclusion reached by scientists from the Medical College of Pennsylvania (USA), who analyzed the sleep and nutrition habits of 29,217 adults. About 46% of survey participants reported short sleep, less than six hours. Less often, 22% of respondents who regularly ate berries, strawberries, and blueberries encountered this problem.
Cottage cheese
Cottage cheese is good for sleep due to 20 micrograms of selenium (36% of the daily requirement) in one serving (100-120 grams). In 2023, scientists from China stated that eating foods rich in selenium improves sleep. This was confirmed by their study involving 22,090 people. Although selenium is not directly involved in the synthesis of melatonin, replenishing its deficiency can reduce the negative impact of reactive oxygen species on brain processes.
Whole grains
The list of products for good sleep also includes rye bread, oatmeal, and flax seeds. They contain whole grain fiber, which supports the health of the intestines, which are called the second brain. Scientists have discovered that a number of intestinal lactic acid bacteria (L. rhamnosus, L. casei, L. brevis) secrete GABA – gamma-aminobutyric acid. In the brain, it serves as an inhibitory neurotransmitter and improves sleep. Due to their significant impact on mental processes, products with live lactic acid bacteria have even been called “psychobiotics”.
But in order for these bacteria to take root in the intestines, it is important not to overeat, eliminate fast food and add fiber to the diet. It also serves as food for the intestinal microbiota and helps its representatives create GABA.
Fish and seafood
There are at least two reasons to eat more fish and seafood. First, they help to replenish the lack of omega-6 and omega-3 polyunsaturated fatty acids (PUFA). In the pineal gland, they affect the activity of the enzyme arylamine-N-acetyltransferase, which converts “daytime” serotonin into “nighttime” melatonin.
Secondly, all seafood is rich in tryptophan and allows you to satisfy your daily requirement for this amino acid.
Bananas
If you sleep poorly and are constantly stressed, include bananas in your diet. This fruit (formally a berry) is rich in potassium, which can increase the duration of the REM sleep phase . It occurs at the end of the sleep cycle and lasts from 5 to 30 minutes. As noted by specialists from the US National Institute of Neurological Disorders and Stroke, recovery processes occur in the deep REM sleep phase.
Nuts
A pack of almonds or peanuts, or more precisely the magnesium contained in these nuts, helps to calm the nervous system. Magnesium ions in the brain bind to GABA receptors. By activating these receptors, magnesium increases the level of GABA, which in turn slows down brain activity and promotes relaxation and good sleep. Many sedatives act in a similar way.
Kiwi
Two fresh kiwis an hour before sleep have a positive effect on sleep quality. The fruit contains serotonin and is rich in vitamins C and E, antioxidants that protect the body’s cells from damage by free radicals. Kiwis also help to replenish the deficiency of folic acid (or vitamin B9), which often manifests itself in insomnia.
Milk with turmeric
Milk is a product that contains both melatonin and tryptophan. These components are already enough to sleep well, but if you add a few of the right spices, you will get “golden milk” from Ayurveda recipes. To prepare it, take:
- ½ cup whole milk (can be replaced with coconut milk);
- 1 tsp ground turmeric;
- ¼ tsp ground ginger;
- ¼ tsp ground cinnamon or 1 whole stick;
- ⅛ tsp ground cardamom;
- 1 tbsp ghee or coconut oil;
- 1 pinch freshly ground black pepper;
- 1 tsp. honey.
The National Center for Complementary and Integrative Health (NCCIH) notes that Ayurvedic medicine has a very small evidence base. But the main component of “golden milk” – turmeric – is actively studied. For example, scientists from South Korea studied the effect of turmeric on the central nervous system of animals and found that it helps to fall asleep faster. The active component of the spice – curcumin – binds to H1-histamine receptors in the brain and has a calming effect. Diphenhydramine and first-generation antihistamines for the treatment of allergies act on the same principle.
How does sweet affect sleep?
On this matter, scientists have different opinions.
Experts from Australia explain: if you eat cake, white bread, or chocolate at night (i.e., products with a high glycemic index), your blood sugar level will quickly increase. The response will be the release of insulin. It facilitates the absorption of neutral amino acids and removes tryptophan competitors from the bloodstream. The level of tryptophan in the brain increases, so sleep comes faster.
James Gangwisch, an associate professor at Columbia University, came to the opposite conclusion. Together with his colleagues, he conducted a large multicenter study and examined the diet of 93,676 women aged 50 to 79. In the participants who did not exclude added sugar from their diet, Gangwisch observed insomnia.
Does alcohol help you sleep better?
It is a mistake to use alcoholic beverages as a “household” sleeping pill. Although alcohol inhibits the central nervous system and promotes rapid falling asleep, such sleep can hardly be called quality. Due to alcohol, the duration of sleep is reduced, and the number of awakenings increases.
In addition, alcoholic beverages suppress the production of antidiuretic hormone, which accelerates urine formation and quickly removes fluid from the body. During healthy sleep, everything happens exactly the opposite: the pituitary gland secretes antidiuretic hormone so that the kidneys retain water in the body and dehydration does not occur.
Dehydration itself can disrupt sleep, and the diuretic effect of alcoholic beverages can also cause a person to wake up.
Where to get serotonin?
We can get melatonin, tryptophan, and many other substances that improve sleep from food. But not serotonin, the precursor of melatonin. The brain synthesizes it itself, and we need to try to help it do this. How can this be done?
- Get your daily dose of sunlight—even nine minutes in the sun boosts serotonin production, improving mood and sleep.
- Reduce your consumption of coffee, chocolate and tea – these products can disrupt sleep because the caffeine they contain suppresses the production of serotonin.
- Move – When you pedal a bike or lift weights, your body releases more tryptophan and converts it into serotonin.
Even more serotonin is released when we are around loved ones for whom we are important. Masahiro Matsunaga from Aichi Medical University (Japan) and his co-authors found that even the thought of loved ones causes a release of serotonin in the brain. So if you can’t sleep, remember a happy moment with a loved one.