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Can Diet Really Affect Your Child’s Behaviour?

Health, Healthy Food
7 min read

Have you heard the saying ‘You’re only as happy as your saddest child’?  It’s not the most uplifting phrase but it may hold a lot of truth.  If your child is struggling with behavioural and mental health challenges, you are likely in the struggle too.

For kids, these struggles can be encountered at all ages and the presented symptoms can often morph from one into another as the child matures. For example, the toddler who frequently experiences meltdowns and tantrums; the school aged child who lacks focus, is hyperactive and has learning challenges; the teen who suffers from anxiety, depression, and poor executive functioning skills. Sadly, these are only a handful of the behavioural challenges on the rise in kids today.    

It is important to look closely at what may be contributing to a child’s symptoms and how small adjustments to diet can help significantly.  This is a path I went down many years ago with my active and outgoing four-year-old son.  He started chewing on his shirt to the point it had holes in it, had difficulties falling asleep and was restless throughout the night once he did find sleep. 

These were early signs of anxiety that quickly disappeared when I investigated deeper into what was contributing to the imbalances and nourished his body with what it needed.  The improvements were so remarkable that it started me on a journey to continue my education in nutrition and create Fuel Nutrition & Wellness so I could help other families.  

How Diet Affects the Brain

First, let’s consider what a child is eating and how it affects brain health. The brain is the most complex organ in the body and, to thrive, it needs to be nourished with nutrient rich foods. The foods we choose as fuel will have a positive or negative impact on the brain which directly affects physical and mental development. High quality foods will support the mind and provide benefits that improve brain function.  Whereas a diet lacking the necessary nutrients will have an opposite effect, enhancing negative cognitive function.  This may present as difficulty with sleep, poor focus, irritability, withdrawal, lack of energy, and impulsivity.  Below are three areas to consider that play a role in brain health. 

Can Diet Really Affect Your Child’s Behaviour? - BC Parent Newsmagazine

Neurotransmitters and the microbiome

Neurotransmitters carry messages around the body. These are important in keeping the brain balanced and high functioning. The microbiome is made up of trillions of microorganisms in the gastrointestinal tract; most of those organisms are bacteria. People often don’t realize how intricately the two are related; they think of neurotransmitters in the brain and microbiome in the gut.  However, most gut bacteria produce neurotransmitters, and these chemical messengers are what help to keep the brain thriving. 

Two well-known neurotransmitters are serotonin and dopamine. They are often referred to as the ‘feel-good hormones’ because they are associated with what keeps us feeling happy, focused, calm, positive and motivated. Did you know that upwards of 90% of the body’s serotonin is produced in the gut? 

If the gut microbiome is out of balance, it is not a realistic expectation for the body to have optimal levels of this particularly important mood stabilizer. Furthermore, children will be unable to properly regulate their emotions, stay focused and thrive mentally with a lack of neurotransmitters. Often the foods that children lean towards are those that are heavily marketed to them. A diet highly favouring processed foods, sugar and high fats will negatively affect the gut’s microbiome. The lack of beneficial bacteria will restrict the production of necessary neurotransmitters and contribute to imbalances within the brain. 

To have a balanced gut, the good bacteria need to be fed with high fibre foods such as berries, leafy greens, and whole grains.  You will often start to see behavioural improvements quite quickly once strengthening the intestinal function.  


When we hear inflammation, we often think of something swelling up on the body. However, it is inflammation inside the body, including the brain, that can be linked to struggles in behaviour. 

The Western Pattern Diet, consumed by many North Americans, is low in fruits and vegetables while high in fat and sodium. This diet contributes to the high levels of inflammation throughout the body, which will consequently also have a negative effect on the brain. Based on the long lineups at fast food chain restaurants, we see kids today are consuming more of this inflammatory diet and less nutrient rich foods. 

Consuming a healthy amount of omega-3 fatty acids is going to keep inflammation at an appropriate level and nourish the brain for optimal development in a child’s formative years. Some nutrients can be produced by our body, but these fatty acids are known as essential nutrients, meaning we can only get them through diet or supplements. There is an even higher need for these omega-3s while children’s brains and bodies are rapidly growing and developing. A diet incorporating plenty of fish, nuts and seeds will provide an adequate amount of this essential nutrient.

Blood sugar

We’ve now discussed some ways brain function improves with the support of a nutrient dense diet, but certain ingredients will also have a negative impact on the brain.  Sugar is one ingredient that not only affects learning function and memory but can also contribute to destructive behaviour. For example, sugar puts the child’s brain in overdrive, affecting mood and behaviour because of constant spikes and crashes in blood sugar.

The imbalance can create a roller coaster of emotions. Additionally artificial sweeteners negatively affect the gut’s microbiome and are known to create anxiety, irritability, and insomnia.  Choosing sweeteners such as honey and maple sugar will lessen the blood sugar spikes while also adding health benefits that regular sugar and artificial sweeteners do not offer. 

Can Diet Really Affect Your Child’s Behaviour? - BC Parent Newsmagazine

To summarize, children will be better equipped to cope with mental stresses when they are eating nutritious foods. A healthy and well-balanced diet can fuel the brain and body to be more alert, think more clearly, improve concentration, lengthen attention span, regulate emotions, and improve mental health in general. It is not a one size fits all diet as the needs of each body is individual.  How the changes are incorporated into the everyday life of the child is important in creating a successful outcome.  There are many ways to make the transition seamless for families. 

Simple dietary changes can make a big difference to a child’s symptoms.  If your child is struggling, I encourage you to reach out to a nutritionist for guidance.  The process is greatly simplified when you have someone to help navigate the journey, a journey that will help support your child in maintaining optimal health.

Christy Donnelly is a Registered Holistic Nutritionist at Fuel Nutrition & Wellness with a focus on pediatrics, mental health, and the gut-brain connection.  She is passionate about getting to the root of health concerns while providing guidance that families can easily incorporate.  If you have any questions, she can be reached through her website at www.yourfuel.ca

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