It is a universal wish of parents around the globe that their children should sleep longer, deeper and wake as little as possible. There is growing evidence that good sleep is important for the child’s mental development. This article will examine whether simple nutritional intervention, for example with foods high in marine omega-3 fatty acids, B vitamins or tryptophan can improve children’s sleep.
Achieving high-quality sleep means falling asleep faster, staying asleep longer (in deep sleep) and waking less frequently for shorter times. Sleep is a naturally recurring, reduced state of consciousness with relatively suspended sensory and motor activity. It is characterized by the inactivity of nearly all voluntary muscles and a decreased ability to react to stimuli.
Sleep is a heightened anabolic state which allows the growth, rejuvenation and healing of the immune, nervous, skeletal and muscular systems. Many of the basic food chemicals that have been eaten whilst awake are synthesized into an extensive series of structural tissues and complex metabolites during sleep. The simple substances which have been ingested during the catabolic (awake) period are synthesized into the complex proteins of living tissue. It follows that high-quality sleep is necessary for the optimal development and growth of children. In addition, sleep helps improve mental and emotional function and has a role in learning and the formation of memories. Neurobehavioural function has been shown to be impaired in children with sleep disorders (1).
The parents of a newborn baby very soon discover the vital importance of sleep in the first few weeks and months. Indeed, the quality and quantity of an infant’s sleep affects its own development and the well-being of everyone else in the household. In infants, new brain connections are built during the sleeping hours which in turn allow the improvement of learning and memory. At all ages, sufficient high-quality sleep is essential for feeling alert, being attentive and having a good mood throughout the next day.
Human growth hormone is secreted by the pituitary gland. Growth hormone is released throughout the day, however in children, the most intense period of release is shortly after the beginning of deep sleep. Several factors affect its production, including nutrition, stress and exercise, but in young children the most important factor is sleep. Lack of adequate sleep in children can lead to slower growth or stunting. However, it is not just stature that is affected. Shortage of sleep can lead to a condition known as growth hormone deficiency which can adversely affect heart, lung and immune system function. Hormones that affect satiety and appetite can also be adversely affected by lack of sleep, which in turn can lead to obesity trigger insulin resistance (a precursor to type 2 diabetes).
Hormones produced by the hypothalamus regulate the daily cycle of sleep and wakefulness. The anabolic state of the body during sleep produces some important biochemical changes, e.g., melatonin levels increase whilst adenosine decreases.
A relaxed state of mind is a prerequisite for sleep. Gamma-aminobutyric acid (GABA) can assist by reducing brain stimulation. GABA can be found in a variety of foods including Chinese barley grass and red ginseng (2,3). The herb lemon balm (Melissa officinalis) can reduce the activity of an enzyme that breaks down GABA, leading to an increase in levels of GABA in the brain and providing a calming effect. A clinical trial has shown that lemon balm can be effective in the treatment of restlessness in children (4). Camomile and valerian are also commonly used in herbal mixtures targeted at relaxation and sleep onset.
Some B vitamins have a role in the synthesis and release of certain neurotransmitters (e.g., serotonin) and neurohormones. Thiamine (vitamin B1) is a cofactor for the enzyme that produces GABA, whilst pyridoxine (vitamin B6) is involved in the synthesis of a number of neurotransmitters including serotonin, dopamine and GABA. High dose niacin has been shown to improve REM (rapid eye movement) sleep in a small adult cohort, whilst some case report data suggests vitamin B12 can assist those who suffer from a disturbed sleep-wake rhythm (5). It is not clear if typical intake levels of B vitamins have an effect on sleep patterns at present.
L-tryptophan is involved in the synthesis of serotonin and increases NREM sleep, but decreases REM sleep. There is some inconsistent evidence that tryptophan can reduce the time taken for onset of sleep (5).
There is emerging evidence that marine omega-3 fatty acids such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) may be important for improving the sleep pattern of children. In a study of children with attention-deficit hyperactivity disorder (ADHD), it was shown that low plasma levels of EPA and DHA were associated with behavioural and sleep problems (6). It has also been shown that mothers who have higher levels of plasma DHA produce infants that have better sleep patterns than those mothers with low levels (7). A study in 2012 provided an intervention of 300 mg DHA per day to mothers from 24 weeks gestation to delivery. There were significantly fewer awakenings of those babies born to the supplemented mothers one and two days after birth (8). In another intervention trial (9), an improvement in sleep in children (aged five to ten years) with ADHD was obtained with a daily supplementation of 440 mg EPA+DHA for three months (note the supplement also contained GLA, magnesium and zinc). In another trial, a daily intervention of 600 mg of algal DHA for four months in healthy children aged seven to nine years in the UK resulted in an average of 58 minutes more sleep and a reduction of almost half in terms of awakenings (10). A very recent study (11) in adults has shown that high plasma EPA and DHA levels reduce the risk of poor sleep that causes depression. Omega-3 fatty acids have been shown to be positively associated with improved sleep efficiency, slow-wave sleep and REM sleep in a small cohort of mainly middle-aged males who were obese and suffered from obstructive sleep apnoea syndrome (12).
In summary, there is encouraging research indicating that specific nutritional interventions may be able to improve children’s sleep patterns, but further randomized controlled trials are required for confirmation.