**2. Substances involved in the sleep-wake regulation and food intake**

Many different neurotransmitters, neuromodulators and hormones have an important role in regulation of sleep and wakefulness, and in eating behaviour. These substances include (in alphabetical order): acetylcholine, adenosine, alpha-MSH (alpha melanocyte-stimulating hormone), cholecystokinin, dopamine, GABA, ghrelin, glutamate, glycine, insulin, histamine, hypocretin (orexin), leptin, MCH (melanin-concentrating hormone), melatonin, norepinephr‐ ine, NPY (neuropeptide Y), prostaglandins, serotonin, somatotrophin and thyrotropin. Little is known about the effect of vitamins and minerals on sleep. They will be discussed shortly later in this review.
