The science of sleep: The hormones that influence its quality

Sleep is a fundamental, yet complex biological process affected by numerous factors, including stress, daily habits, and diet. While it is commonly believed that the need for rest is in accordance with the physical and mental levels of fatigue, sleep quality is significantly determined by the balanced function of specific hormones. More specifically, melatonin, serotonin, GABA, and cortisol regulate the onset, duration, and overall quality of sleep.

Melatonin – The sleep hormone

Melatonin is the primary hormone responsible for regulating circadian rhythm, the body’s internal biological clock. Produced by the pineal gland in the brain, it is released when natural light decreases, signaling to the body that it is time to sleep. However, prolonged exposure to artificial light, particularly the “blue light” emitted from screens, smartphones, and computers, can suppress melatonin production, making it harder to fall asleep. To naturally boost melatonin levels, try consuming foods that contain or promote melatonin production, especially during the evening, such as cherries and bananas, walnuts and almonds, oats, rice, or warm milk.

Serotonin – The hormone of relaxation and well-being

Serotonin is a neurotransmitter that plays a key role in mood regulation and anxiety control, directly impacting sleep. The human body utilizes serotonin in order to produce melatonin, meaning that a deficiency in serotonin can lead to insomnia or restless sleep, negatively affecting rest quality. Foods that enhance serotonin levels include chicken and turkey, salmon and fatty fish, pumpkin and sunflower seeds, dark chocolate, and cocoa.

Tryptophan – The amino acid that promotes relaxation

Tryptophan is essential for sleep regulation, as the body converts it into serotonin and melatonin. The consumption of foods that are rich in tryptophan, particularly in the evening, can facilitate sleep onset and improve sleep quality. Eggs, dairy products (yogurt, cheese, milk), lentils, chickpeas, and chamomile -known for its calming properties- support relaxation and promote better nighttime rest.

GABA – The brain’s natural sedative

GABA (gamma-aminobutyric acid) is one of the brain’s primary inhibitory neurotransmitters, contributing to stress reduction and relaxation. It calms the nervous system, helping it slow down and unwind. As a result, troubled thoughts and anxieties subside, leading to deeper, more restful sleep. Foods that naturally boost GABA production include seaweed, cashews and almonds, mushrooms, potatoes (especially sweet potatoes), broccoli, and spinach.

Cortisol or the stress hormone – Sleep’s greatest enemy

Cortisol, commonly known as the stress hormone, is responsible for body’s response to stressful situations. Elevated cortisol levels during the night can severely disrupt sleep, causing persistent insomnia or poor-quality rest. To keep cortisol levels low, essential particularly in the late afternoon and evening, it is important to avoid caffeine, alcohol, heavy or fatty meals, as well as intense physical activity.

The human body possesses all the necessary mechanisms to facilitate sleep and relaxation naturally. It is on our hands to support these functions by maintaining a hormonal balance, allowing both our bodies and minds to experience deeper and more rejuvenating sleep every night.