You may wonder, can vitamin deficiency cause insomnia? Just such a thing has been suggested by some in alternative medicine. It is said that one of the most common sleep ailments, insomnia, may occasionally be caused by a vitamin deficiency. Though vitamin deficiencies may cause various neurological disorders, it is not a recognized cause of insomnia.
Some of these alternative medicine practitioners recommend various remedies for insomnia, including the consumption of vitamin-rich foods and even "a tablespoon of honey with milk." Although eating a balanced diet is important, and honey and milk may be comforting and tasty, it is unlikely that vitamin supplementation will cure a case of insomnia. In reviewing the medical literature, there is no scientific evidence supporting these claims.
There are other recommendations that may indeed help with insomnia, such as stress reduction, daily physical activity, and creating an environment that is conducive to sleep. These are part of the sleep hygiene guidelines, and may improve sleep as part of behavioral modification. For those who suffer from insomnia, evidence-based treatments are available and should be sought from reputable medical practitioners.
Bottom line: Unfortunately "vitamin-deficiency insomnia" is not a recognized disorder and the use of vitamin supplementation to cure insomnia is likely little more than a waste of vitamins.