Sleep affects brain function, which is not only a common phenomenon in vertebrates, but is also as a result of environmental, psychophysiological and pharmacological factors and remains one of the mysterious sciences. Sleep disorders (insomnia and so on) constitute a global epidemic that affects 45% of the world's population, but less than 1% have been treated by functional foods for insomnia prevention; sleep disorders cost the US $150 billion each year.

Insomnia not only remains a significant risk factor for depression, anxiety, fibromyalgia, rheumatoid arthritis, whiplash, arthrosis, osteoporosis, headache, asthma and myocardial infarction, but is also significantly associated with the incidence of angina, hypertension, obesity and stroke.

Dietary supplementation of tryptophan can stimulate serotonergic activity and promote sleep, whereas serotonin released into diencephalon and cerebrum might play a key inhibitory role in insomnia prevention. Prolonged-release melatonin was approved in Europe for insomnia prevention, which suggest a beneficial role of sleep-wake cycle stabilization in the treatment of insomnia. Benzodiazepines for rapidly modulate GABA signaling in central neurons are widely used in the treatment of a variety of neurological and psychiatric conditions including anxiety, insomnia and epilepsy.

Insomnia may be influenced by an epigenetic control process between sleep mechanisms and gene-environment interactions having an impact on brain plasticity. Insomnia is 43% to 55% heritable in humans.

GABA is an inhibitory neurotransmitter and promotes parasympathetic activity for improved sleep, which is a functional food ingredient of safety use. Some nutrients (calcium, potassium and magnesium) are associated with improved sleep.

Rice and wheat are staple foods of more than 70% of the worlds’ populations. The loss of GABA from brown rice to white rice in the world in 2013 was estimated to be 70,323 tons; The loss of potassium and magnesium as well as calcium from brown rice to white rice in the world in 2013 were 929,765 tons and 485,875 tons as well as 31,599 tons, respectively. The loss of potassium and magnesium as well as calcium from whole grains to white flour of wheat in the world in 2013 were 4,782,778 tons and 1,414626 tons as well as 162,944 tons, respectively. The loss of GABA and other nutrition-related sleep from whole grains to polished grain foods are key factors that cause insomnia.

Foods rich in sugar, caffeine, green tea, etc can contribute to insomnia.Sleep duration is inversely associated with higher intake of sugar. Protein and carbohydrate intake in diet is associated with insomnia. Short sleep duration is associated with increased energy consumption. Excessive caffeine consumption (i.e >500 mg per day) can cause negative health consequences such as insomnia, psychomotor agitation, headache and gastrointestinal complaints. In addition, smoking is associated with increased insomnia.

Traditionally, lettuce has been recommended for its hypnotic property, with the main component found in n-butanol fraction of this plant.

Cherry ingestion may contribute to establish a high-quality sleep and be used as a potential nutraceutical tool to prevent sleep disorders with the advancing of age.

The consumption of a tart cherry juice concentrate provides an increase in melatonin that is beneficial in managing disturbed sleep.

The walnut may contribute to improved sleep based on the highest content in the antioxidants melatonin, serotonin and total polyphenols.

Kiwifruit consumption may improve sleep onset, duration and efficiency in adults with self-reported sleep disturbances.