Poor sleep is a common complaint for both children and their parents. Fatigue in children can cause a number of problems in waking life, including decreased concentration, behavioural issues, school absenteeism, lower immune resistance and less emotional resilience.
With many potential contributing factors or conditions that may cause sleeping difficulties in children, diet and micronutrient deficiencies have been identified as a possible treatment strategy. A recent 2018 systematic review and meta-analysis showed an association between consumption of fruits and vegetables and adequate sleep duration in children.
A 2015 study in 98 children between the ages of two and 18 years found that a diet which incorporated green vegetables, beef, whole milk and full-fat butter improved sleep throughout the night and resulted in less fatigue and need for naps throughout the waking hours.
Researchers attributed these changes to the micronutrient composition of these foods including magnesium, iron, B complex vitamins, vitamins C and E as well as fatty acids. Intake of green vegetables had the strongest benefits for cognitive fatigue, thought to be as a result of vitamins A and C increasing the absorption of minerals such as magnesium, zinc and iron.
Magnesium, in particular, is identified as especially important for improving sleep. Supplementation in individuals with insomnia exhibited significantly increased sleep time efficiency, and both renin and melatonin levels.[3 ]Magnesium is involved in serotonin production, which plays a role in sleep quality, as well as the sulfation of adrenal hormones, of which an imbalance may also contribute to poor sleep. Vitamin B6 is also a helpful cofactor in these processes. 
Vitamin B6, alongside tryptophan (involved in the synthesis of serotonin) and melatonin (the end product of the serotonergic pathway), has demonstrated efficacy in inducing spontaneous sleep in children who were undergoing investigations for early deafness via an auditory brainstem response (ABR) test. This provides an alternative to the usual pharmaceutical sedation.
Zinc is another important nutrient for enhancing sleep in children, with research demonstrating a link between sufficient blood zinc concentration and good sleep quality in children aged three to five and 11-15 years of age.  Zinc is involved in neurotransmitter production intrinsic to sleep, such as gamma amino-butyric acid (GABA) and n-methyl-D-aspartate (NMDA) balance.  A healthy balanced diet with plenty of fresh fruit and vegetables is vital to maintaining healthy sleep patterns in children. Minerals such as magnesium and zinc, as well as vitamin B6, may also be helpful adjuncts where dietary intake isn’t sufficient in supporting optimal sleep in children.
- Steenbruggen TG, Hoekstra SJ, van der Gaag EJ. Could a change in diet revitalize children who suffer from unresolved fatigue? Nutrients 2015(7)1965-1977. 2 [Full Text]
- Córdova FV, Barja S, Brockmann PE. Consequences of short sleep duration on the dietary intake in children: A systematic review and metanalysis. Sleep Med Rev 2018:S1087-0792(17)30194-30196. [Abstract]
- Abbasi B, Kimiagar M, Sadeghniiat K, et al. The effect of magnesium supplementation on primary insomnia in elderly: a double-blind placebo-controlled clinical trial. J Res Med Sci 2012;17(12):1161-1169. [Full Text]
- Hechtman L. Clinical naturopathic medicine. Chatswood: Elsevier, 2012. [Source]
- Volpe AD, Lucia A, Pirozzi C, et al. Comparative study between the use of melatonin and a solution with melatonin, tryptophan, and vitamin B6 as an inducer of spontaneous sleep in children during an auditory response test: an alternative to commonly used sedative drugs. J Int Adv Otol 2017;13(1):69-73 [Full Text]
- Ji X, Liu J. Associations between blood zinc concentrations and sleep quality in childhood: a cohort study. Nutrients 2015;7(7):5684-5696. [Full Text]