Why Won't My Child Sleep? What Is Behind Behaviour, Energy, and Sleep Problems in Kids
By Kylie Sartori | Kylie Sartori Naturopathy, Spotswood, Melbourne
If you are reading this at 11 pm because your child will not settle, or because you are trying to understand why your previously easy-going kid has become anxious, reactive, or impossible to get out of bed in the morning, you are not alone.
Sleep problems, behavioural changes, low energy, anxiety, hyperactivity, and difficulty concentrating are among the most common concerns parents bring to me in clinic. And the most important thing I can tell you is this.
These are not just phase problems.
They are not simply about screen time or parenting style or needing a firmer bedtime routine, though those things matter. In most cases, when a child is genuinely struggling with sleep, mood, energy, or behaviour in a persistent way, there is something physiological happening underneath that is worth investigating.
And it is almost always connected to the gut.
Why the Gut Is Usually Where the Answer Lives
Your child's gut microbiome does far more than digest food.
It produces neurotransmitters, including serotonin and GABA, that directly regulate mood, anxiety, and sleep. It communicates constantly with the brain through the gut-brain axis, influencing how calm or reactive the nervous system is at any given moment. It regulates the immune system, manages inflammation, and determines how well nutrients are absorbed and delivered to every cell in the body, including the brain.
When the gut microbiome is disrupted, whether from antibiotics, a diet low in plant diversity, processed food, stress, or illness, all of those functions are impaired simultaneously. A child with a disrupted microbiome is often a child who is not sleeping well, whose mood is unpredictable, whose energy is low, and whose behaviour is harder to understand.
This is why looking at the gut first, rather than trying to manage each symptom separately, produces the most meaningful and lasting results.
The Nutrients That Most Affect Children's Behaviour, Sleep, and Mood
Nutrient deficiencies are one of the most consistent findings in children with sleep, behavioural, and mood concerns. And what makes this complicated is that a child can be eating reasonably well and still be deficient, because poor gut health impairs absorption before the nutrients can be used.
Here is what I look for most often.
Magnesium is involved in over 300 enzymatic processes in the body and is essential for nervous system regulation, muscle relaxation, and sleep. Low magnesium in children presents as restlessness, difficulty settling at night, nightmares, muscle tension, and irritability. It is one of the most common deficiencies I see in children with sleep difficulties and is depleted further by stress, sugar, and a diet low in whole foods.
Zinc plays a critical role in neurotransmitter function, immune health, and gut lining integrity. Low zinc is consistently associated with ADHD-like presentations, low mood, impaired immune function, poor wound healing, and disrupted sleep. It is also essential for the production of stomach acid, which means zinc deficiency compounds absorption problems across all other nutrients.
Iron is essential for the production of dopamine and serotonin, the neurotransmitters most directly involved in mood regulation, motivation, and sleep onset. Low iron in children presents as difficulty falling asleep, restless legs, poor concentration, fatigue, pallor, and in some cases behavioural changes that can look like hyperactivity or emotional dysregulation. Iron deficiency is surprisingly common even in children who eat meat, particularly where gut absorption is compromised.
Omega-3 fatty acids, particularly DHA, are the primary structural fat in brain tissue. Adequate DHA is essential for neural communication, emotional regulation, focus, and sleep architecture. Children with low omega-3 status frequently present with behavioural difficulties, mood instability, poor concentration, and disrupted sleep. The brain is still developing rapidly throughout childhood, and DHA availability during this window matters significantly.
Vitamin B12 supports the production of melatonin and the health of the nervous system. Low B12 in children can cause poor sleep onset, restless sleep, irritability, and in more significant deficiency, neurological symptoms. It is particularly relevant in children who eat limited animal protein or who have compromised gut absorption.
Vitamin D influences mood, immune function, and inflammation, all of which affect how a child feels and behaves day to day. Deficiency is common even in Australia and is worth testing rather than assuming adequate sun exposure is sufficient.
The important thing to understand about all of these is that supplementing without addressing gut absorption first is often a costly and ineffective approach. If the gut lining is compromised or the microbiome is disrupted, supplements will not be absorbed well enough to make the difference they should. Addressing the gut comes first.
What Else Can Drive Sleep and Behaviour Problems in Children
Beyond nutrient deficiencies, several other factors consistently show up in children who are struggling.
Food additives, colours, and preservatives have a well-documented association with hyperactivity and behavioural changes in children. Artificial colours, particularly the Southampton six group, sodium benzoate, and various flavour enhancers, affect neurological function and behaviour in sensitive children. Reducing or removing processed foods with these additives is often one of the most immediately noticeable dietary interventions.
Food intolerances can drive low-grade gut inflammation and systemic symptoms, including disrupted sleep, mood changes, skin reactions, and behavioural difficulties. Gluten and dairy are the most common, but reactions to eggs, soy, and certain food chemicals like salicylates and amines are also seen regularly in children with complex presentations. The delayed nature of these reactions makes them genuinely difficult to identify without proper investigation.
Sugar and blood sugar instability directly affect the nervous system and mood. A child running on a high sugar diet experiences repeated blood sugar spikes and crashes across the day that manifest as hyperactivity, irritability, difficulty concentrating, and poor sleep quality. Stabilising blood sugar through consistent whole food meals and reducing sugar intake makes a faster and more visible difference to behaviour than most parents expect.
Toxin exposure from chemical cleaning products, plastics, pesticides on food, and synthetic fragrances in personal care products contributes to the overall inflammatory and neurological burden on a child's developing system. Reducing this exposure through simple swaps is a low-effort intervention that compounds positively over time.
Screen time and light exposure in the hours before bed suppress melatonin production and keep the nervous system alert when it should be winding down. This is well established in the research and is worth addressing as part of any sleep support protocol, particularly for older children and teenagers.
What Testing Can Tell You
One of the most useful things you can do when a child has persistent sleep, behavioural, or mood concerns is to stop guessing and start testing.
A comprehensive stool test through functional testing assesses the gut microbiome, markers of gut inflammation, intestinal permeability, and digestive enzyme function. This gives a clear picture of what is happening in the gut that is driving the symptom picture, rather than treating each symptom in isolation without a map.
Alongside gut testing, nutrient testing through blood work for iron studies, zinc, B12, vitamin D, and omega-3 status removes the guesswork from supplementation and allows treatment to be targeted and effective from the outset.
Hair mineral analysis can also provide useful information about mineral status and toxic metal exposure, though it works best as a complement to blood and stool testing rather than as a standalone assessment.
The combination of gut testing and nutrient assessment gives us the clearest possible picture of what your child's body specifically needs, which is what makes treatment actually work rather than producing temporary improvements that do not hold.
Practical Steps That Make a Difference
Remove what is disrupting the gut and nervous system
This means pulling back on processed foods, refined sugars, artificial additives, and chemical exposures where possible. It means being thoughtful about unnecessary medications, particularly repeated courses of antibiotics and regular use of ibuprofen, both of which significantly disrupt the gut microbiome and lining. It means using natural cleaning products and reducing plastic exposure where practical.
None of this needs to be perfect. Reducing the load matters more than elimination.
Build the diet around whole foods and plant diversity
Vegetables, fruits, legumes, whole grains, quality protein, healthy fats, nuts, and seeds provide the nutrients and prebiotic fibre that both the gut microbiome and the developing brain depend on. The greater the variety of plant foods across the week, the more diverse and resilient the microbiome becomes, and the better a child's gut can support their mood, sleep, and behaviour.
Getting variety into children's diets takes creativity. Smoothies, soups, homemade sauces, and involving children in food preparation all help. Progress over perfection is the right approach.
Support the gut with probiotics and fermented foods
A practitioner-grade probiotic appropriate for the child's age and picture makes a meaningful difference to microbiome health, particularly where there has been antibiotic use or a history of gut symptoms. Fermented foods like natural yoghurt and kefir provide additional beneficial bacteria and are often well-tolerated by children when introduced gradually.
Protect sleep through consistent rhythms
A consistent bedtime, a dark and cool room, screens off at least an hour before bed, and a calming wind-down routine are the foundations of sleep hygiene for children. Where sleep difficulties are significant and persistent, herbal and nutritional support can assist with sleep onset and quality alongside these habits.
Work with a practitioner who can test and treat specifically
This is where the biggest gains come from. A naturopathic consultation gives you a clear picture of what is actually driving your child's symptoms and builds a treatment plan that addresses the cause rather than managing each symptom one by one.
Working Together
Parenting a child who is not sleeping, whose behaviour is hard to understand, or who seems to be running on empty is genuinely exhausting. The pattern often makes more sense than it appears once we have the right clinical information.
If you would like to take the guesswork out of what is happening for your child, we can work together to investigate properly and build a plan that addresses the full picture.
I see children and families in person at my Spotswood clinic in Melbourne and via telehealth across Australia.
Book a consultation
You can also read more about children's gut health and what conditions I work with, or explore functional testing for children.
Frequently Asked Questions About Children's Sleep and Behaviour
Could my child's sleep problems be nutritional? Very possibly. Magnesium, iron, B12, zinc, and omega-3 deficiencies all directly affect sleep quality, sleep onset, and the nervous system regulation that sleep depends on. These deficiencies are more common than most parents realise, particularly in children with poor gut absorption, limited dietary variety, or a history of antibiotic use. Testing nutrient status is one of the most useful starting points when sleep difficulties are persistent.
How does gut health affect a child's behaviour? The gut produces a significant proportion of the body's serotonin and communicates directly with the brain through the gut-brain axis. When the gut microbiome is disrupted, neurotransmitter production is affected, inflammation increases, and the nervous system becomes more reactive. Children with gut dysbiosis frequently show increased emotional dysregulation, anxiety, difficulty concentrating, and mood instability alongside their physical gut symptoms. '
My child has been on multiple courses of antibiotics. Could that be contributing? Yes significantly. Each course of antibiotics depletes beneficial gut bacteria, and repeated courses compound that disruption over time. The gut microbiome in young children is still establishing itself, which makes the impact of antibiotic use during this window particularly significant. Targeted probiotic support after antibiotic courses, alongside dietary support to rebuild microbiome diversity, is one of the most important things you can do to protect your child's gut and nervous system health.
At what age can children take supplements? Nutritional supplements are safe from infancy when they are appropriate to the child's age and prescribed by a qualified practitioner. The right product, dose, and form all vary significantly by age, which is why a practitioner recommendation is more reliable than a general retail product. For young children, powders and liquids that can be added to food or drinks are often the most practical format.
Could food intolerances be causing my child's behavioural issues? Yes, and this is more common than most parents are told. Food intolerances in children can manifest as behavioural changes, mood instability, difficulty sleeping, skin reactions, and digestive symptoms, often without obvious digestive complaints. The delayed nature of the reactions makes them genuinely difficult to identify without proper investigation. A structured elimination and reintroduction process guided by a practitioner, alongside gut testing where appropriate, is the most reliable way to identify whether food intolerances are contributing.
Kylie Sartori is a degree-qualified naturopath based in Spotswood, Melbourne, specialising in children's health, gut health, family wellbeing, and nutritional medicine. She offers in-person consultations at her Spotswood clinic and telehealth appointments for clients across Australia. Book an appointment | Learn more about Kylie | Conditions treated | Functional testing
