Does what children eat influence their emotional well-being? Looking at the impact of diet on child/youth mental, social and emotional health
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There are a multitude of inter-related factors of course which contribute to the mental and emotional health challenges of children and young people and it is very rare that any single individual factor is “the” reason as to why a child or young person experiences these difficulties.
However, for us as professionals working in child/teen mental health - understanding and addressing possible individual contributing factors still has the potential for us to help improve mental health in the young people we work with.
In this article I’d like to look at one particular factor which has come under growing scrutiny over the last 25 years: diet and nutritional intake. The growing interest in this area means there have now been hundreds of studies linking diet and mental health. While traditionally much of this research has been focused on adults, studies of children and adolescents has increased substantially in the last few years. Here is an overview of some of the research findings I thought might be of interest to us working with children/young people with mental health or emotional well-being challenges
Why might diet impact children’s mental health and emotional well-being?
At an intuitive level, the idea that food affects how children feel and act makes sense—we instinctively understand that children build and maintain their bodies and brains from the building blocks of what they eat (and it is worth noting that during childhood, the brain uses a much larger proportion of the body’s energy than it does in adulthood).
Beyond the level of intuition however, there are a number of specific biological theories proposed to explain some of the plausible mechanisms for how diet might influence mental health. I’ve outlined some of these below for your interest – keep in mind that this is just a selection of some of the theories - there may be more of them and all of them are somewhat speculative at this stage.
1. Inflammatory Responses: One hypothesis linking diet and mental health suggests that poorer-quality diets increase pro-inflammatory cytokines in our bodies. These reduce anti-inflammatory processes and it is thought that they may result in low-grade, chronic inflammation, which as it crosses the blood–brain barrier interferes with brain and mood function (sometimes referred to as neuroinflammation).
2. Neural Plasticity and BDNF: A compound called brain-derived neurotrophic factor (BDNF) is essential to help the brain form and reorganise connections – and manage mood and mental health – and diet quality appears to be linked with lower levels of BNDF.
3. The Gut–Brain Axis: The gut microbiota consists of trillions of microorganisms that inhabit the digestive system. Although the composition of gut microbiota is influenced by genetics and the environment – it is also at least partly influenced by diet, with “healthier” dietary patterns linked with greater microbial diversity. The gut microbiota influences the production of neurochemicals such as serotonin and dopamine (some of this production happens in the gut, not the brain). It is thought that a lower degree of microbial diversity may influence difficulties with neurochemical production and use - which impacts mental and behavioural health. Many studies show a relationship between gut microbiota composition and mental health.
4. Mitochondrial Dysfunction: Mitochondria are responsible for energy production in cells. Poorer-quality diets appear to impair mitochondrial function. It is theorised that this potentially reduces energy availability in brain cells which then impacts on mental health. There does appear to be associations between mitochondrial dysfunction and various mental health conditions.
5. Oxidative Stress: Poorer diets are associated with excessive levels of a state called oxidative stress and damage in our cells. Higher oxidative stress markers and lower antioxidant defences have consistently been observed in individuals with depression and other mental health disorders
As you can see, there are a number of plausible mechanisms by which poorer diet might impact on mental health. The explanations above are simplified – keep in mind that all of these mechanisms are highly interconnected and so it is likely that multiple processes operate simultaneously - for example, inflammation may increase oxidative stress, oxidative stress may impair mitochondrial function, and mitochondrial dysfunction may affect the gut microbiome.
Beyond theory to research
All of these theories sound plausible – and there is evidence for these theories in animal models as well as some studies linking various aspects of these biological changes with worsening mental health. But we also need real world evidence in children/young people to be able to definitively conclude that diet makes an impact on well-being. There are six types of research on this topic which we might look at to help us understand this question. These are listed below.
1.Epidemiological intergenerational research showing rise in poorer diets and mental health concerns
Over the last 50 years there has been a major expansion in industrial food processing and the availability and consumption of ultraprocessed foods. Not surprisingly, research also suggests that globally many children now consume far more of these ultra-processed foods than in the past, and in turn less whole foods (including vegetables and fruits for instance).
Of interest is that this increase in poorer diet over the last 50 years has occurred at the same time as an increase in the prevalence of mental and emotional health difficulties in children. Of course we can’t draw any firm conclusions from these two corresponding changes in society (because of course they have also been accompanied by corresponding rises in many other factors - increases in technology use, better awareness of mental health difficulties, decrease in physical exercise in children – just to name a few), but it is at the least an interesting observation.
2. Observational (Correlational) Studies linking individual children’s diets with increased likelihood of MH difficulties
Another area of research are the many hundreds of observational (correlational) studies in which researchers investigate the diet of a particular group of children, youth and families about (or measure) their diet, and investigate the same group of children’s mental health and emotional well-being. The results of these studies are relatively consistent: almost every one of them (at least that I have read – and of course as a caveat I’m keeping in mind the problem whereby only positive studies get published) show a link between children/teen’s poorer diet quality and their poorer mental health. Just for example – a review by Wang et al (2022) of 32 studies involving thousands of children and young people found that higher symptoms of depression in kids and teens were related to a lower dietary intake of fruits, fiber, vegetables, magnesium and fish, a review by Malmir (2022) found that higher levels of processed and “fast food” consumption was linked to increased odds of psychological distress in children and teens, and a review by Khazdouz et al (2024) of 9 studies of over 58 thousand children found a link between higher processed foods and worsening ADHD symptoms.
However as you well know this type of research cannot provide causation and we don’t know for sure that the poorer diet of these kids and teens in these studies is what is causing these children to have more emotional health difficulties. I’m sure those of us who interact with these children often will immediately be aware that it is quite possible that these children and young people’s mental health difficulties may themselves be causing their poorer dietary behaviours with children and young people struggling with their mood, behaviours, thinking and impulses finding it much more difficult to each in healthier ways than their peers.
3. Prospective cohort studies linking earlier poorer diet with later mental health difficulties
One way of evaluating this opposite causal theory (ie that it is mental health difficulties which cause children’s poorer diet and not the other way around) is by looking at prospective cohort studies where researchers look at groups of children’s diet early in life and then follow these groups of children over a few years to then examine their mental health outcomes later in childhood. As you can imagine, this type of study would make it somewhat less likely to assume that mental health difficulties are what are driving dietary patterns, as the poorer diet appeared earlier than the mental health difficulties.
One of these studies was called the Norwegian Mother, Father and Child Cohort Study (MoBa) and it followed approximately 40,000 children, collecting dietary data from pregnancy through early childhood. Then, at age 8, children were assessed for attention, ADHD diagnoses, anxiety, depression, and externalising behaviours. The results of this study found that less healthy diets in early childhood were in fact associated with a range of poorer mental health outcomes when children were 8. Another similar study followed approximately 3,000 adolescents over two years and found that a teen’s less healthy diet quality at the beginning of the study predicted their worse mental health later (and conversely that a teen’s improvements in diet over that 2 year period were associated with later improvements in mental health).
These type of studies help us be a little more sure that it is not just mental health difficulties which cause a less healthy diet – again, because the less healthy diet came first. However, it’s worth noting that not all prospective studies like these above have found significant associations between earlier diet and later mental health difficulties. And more importantly - these prospective design studies cannot rule out the idea that some other third variable – like genes, family environment, or socioeconomic factors – is what is causing both the mental health difficulties and the poorer diet. In other words, it is possible that a less healthy diet early in childhood acts as a “marker” of these other (genetic, environmental) variables (ie poor diet is a flag for a specific gene) – and that these variables are what leads to the mental health difficulties, rather than the diet itself.
4. Diet Intervention Studies
A better test of whether diet issues are causing mental health difficulties in children are studies which try to change children’s diets – and see whether their mental health difficulties improve (let’s call these diet intervention studies). These studies are very expensive and hard to do, but those that have been done do generally find that improving kids and teens nutritional intake does lead to positive results for many children. For example: Zhou et al. (2025) reviewed 26 studies on healthier diet intervention studies for children and reported improvements in depression and emotional functioning in children, Thege et al. (2025) found small but significant effects of general dietary improvements on aggressive behaviour in children and perhaps more surprisingly and controversially, Yu et al. (2022) reviewed 7 dietary intervention studies for ASD and ADHD and found on average children showed a reduction in core symptoms when on gluten-free and ketogenic diets.
However, before we start suggesting to caregivers they should be opening pantry doors and frantically tossing out any processed packets of food, it is important to keep in mind two important factors.
First we should be aware that not all diet intervention studies show these positive effects – some don’t find any impact at all. To be fair - we should note that diet intervention studies are plagued by poor adherence - it is really, really hard for many children and young people (and their parents) to change their diet substantially enough or for long and so some of the diet intervention studies which do not show any (or much) change might just have suffered from this poor adherence issue, not the fact the diet changes weren’t effective.
Second – the diet intervention studies which do find positive mental health changes are often “low quality” with small numbers of children/youth involved, and short follow up periods and more importantly – a lack of control groups. Given families and children generally have an expectation that they “*should* and *will* have their mental health improve from eating more healthily - it is possible that this expectancy itself which makes the symptoms improve, not the diet itself. Without an effective control group (for example, having another group of children undertake not a diet intervention but instead say an exercise intervention which they might also expect to have a beneficial effect on mental health) – the researchers can’t separate out what improvements have happened as a result of expectancies rather than the diet change itself.
5. Supplementation Intervention Studies
Given the challenges of managing expectancies in diet intervention studies, researchers have also examined whether nutrient supplementation (ie keeping the same basic diet, but adding in vitamin pills) for children improves mental health outcomes. Given that supplementation studies are able to include “placebo control” (ie one group of children take a sugar pill and another group of children take the supplement under examination) where children and families don’t know what group they are in, they avoid some of the expectancy effect described above. And theoretically, if it is shown that giving children more nutrients directly through a pill improves mental health, we might be able to conclude that increased nutrition is linked to better well-being, especially if we have ruled out expectancy effects.
There are many types of supplements which have been studied in these studies, but the most common ones I have seen examined in the literature include the following: vitamin D, omega-3 fatty acids, probiotics/prebiotics, B vitamins/folate, and iron.
I have read many of these studies recently – and it’s a big area. From what I can see it seems there are many mixed findings in these studies. For instance, a review of studies into B-vitamin supplementation reported that several (but not all) studies found a reduction in children and youth anxiety and depression after treatment. A review of studies on iron supplementation found it was often helpful for anxiety and fatigue (and note this was true even in non-anaemic youth) but not consistently helpful for attention or depression. A review of vitamin D supplementation concluded that there have been reductions in children and young people’s depressive and behavioural symptoms, but mostly if children/young people were deficient. Reviews of probiotic and omega-3 supplementation studies show inconsistent effects – some studies show positive effects and others do not.
Because of the mixed findings, Australian guidelines take an (appropriately in my view) cautious approach and so do not generally support blanket recommendations for supplementation for mental health concerns in children and adolescents.
Still, the fact there are several studies which have controlled for placebo/expectancy effects and go on to find an increase in mental health in at least some children does add a persuasive element to the theory that healthy nutrition may well have a positive impact on many children’s mental health.
So what should we conclude – and what should we encourage families do?
The research above has flaws and mixed findings – and so we probably can’t make definitive conclusions about any individual child/teen. However the preponderance of the result, plus the plausible theoretical mechanisms suggests it would be prudent to at least consider that there may be an impact of diet on our children/young people’s mental health.
I want to make clear that any specific recommendations about diet or supplements for children and young people is well outside of my scope as a psychologist. However, here are some practical strategies we might like to consider when working with young people:
1) If a parent/caregiver (or ourselves) have reported concerns about a child/teen’s nutritional intake (very common of course in children who are neurodiverse, those with anxiety or trauma histories), we might like to recommend the caregiver talk to their child’s GP and ask for their input and opinion. The GP may consider testing for deficiencies, or may be able to give the family some advice about diet or supplements.
2) Other practitioners who we might suggest it be helpful to consult include dieticians/nutritionists or a natural health practitioners who work with food and diet. Speech therapists can also help with feeding or swallowing issues and OTs may be able to help with sensory difficulties associated with food and eating.
3) We want to encourage caregivers to talk with children and teens about the importance of diet for their health and mental health (and we can do the same). What to say will depend on each child, their age and situation but we might use sentences such as: Food helps our brain and body do their jobs. When we have healthy food, this helps us play, think, learn and feel happier, like having enough petrol for our body. Some scientists have found that people who have enough healthy foods to eat feel better and happier.
As well as providing information like this, we can also ask children questions to find out their feelings and understanding about food. For example we might ask: What type of food feels good to you and your body? When you eat and drink enough healthy foods – how do you think that changes how you feel? Are there any foods which you feel like you could eat more of to help you focus/play/be happier?
4) When talking with children and young people about food, we should recommended to caregivers to focus on health and well-being (how and what we can eat to help our bodies work), rather than “moral” instructions about food (this is “bad” and “good” food, eating this is “naughty” or “wrong”). We should also support caregivers to focus on health and well-being rather than weight or size, (ie this is fattening, or you need to eat this or that in order to avoid putting on weight).
5) We want to help parents to understand that many children experience fear, anxiety and involuntary disgust responses to (including textures and tastes) rather than thinking their food decisions are just “bad behaviour”. Sensitivities and anxieties about food are particularly likely for children with mental health conditions and for those are neurodiverse (and children/teens who struggle with this issue significantly more than the average child might be diagnosed with a condition called Avoidant Restrictive Food Intake Disorder). Understanding anxiety, fear and involuntary disgust responses in children helps parents to use empathy and support when working towards improving and widening the diversity of children’s dietary intake. We might suggest they use sentences such as: I know you feel worried about this food, or I am sorry you are finding this hard, and How can I help you feel more comfortable eating healthy foods?
If we are undertaking an exposure process with children/teens to help them increase their healthy diet variety, we will of course want to ensure we have training in this area. Without going into detail about how this might be done – a quick reminder of some of the general principles which include a) gaining assent and understanding first (helping children/teens understand the benefits first), b) moving very slowly and gradually and at a pace which doesn’t induce unnecessary distress and c) ensuring increases in brave behaviours are frequent and consistent.
6) Some parents find the Ellyn Satter Division of Responsibility (check out the Ellyn Satter Institute online) model helpful – this is a model in which caregivers are responsible for what food is provided, when it is provided and where it is provided - and children are responsible for how much they eat and whether they eat.
7) It is usually helpful to think about helping families, young people and children with their nutritional intake as a marathon rather than a sprint. Changes might need to be done very slowly and gradually, and with the goal being a lifetime healthy diet rather than a ‘’perfectly’’ healthy diet this month.
I hope the above has provided you with some “food for thought” (sorry ). Let me finish by remembering that it is important to ensure parents/caregivers to are not subject to any feelings of self-blame, shame or guilt about their child/teen’s diet. We need to remind them that children/teens do not have mental health difficulties “just” because they are not eating well – this is an overly simplistic understanding of mental health. And regardless, helping children and young people have balanced and healthy diets is not easy. So we want to help caregivers be kind to themselves through this process, and help them get some support and help if they need it.
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