How to work out if pesky parasites are making your kids moody and unfocused

Parasites, those unwelcome guests in our gut, may be causing more trouble than you could ever imagine. Beyond stomach discomfort, research is stacking up to suggest these pesky little scroungers could influence our children’s mood, learning and social skills. If you have a child who struggles to regulate their mood or you have a little firecracker on your hands who is making family dynamics challenging to manage, then you may wish to explore the possibility of a little unwanted guest living in their belly.

How can I tell if my child has parasites and where do they come from?

How do you know that parasites are a problem for your child? Aside from seeing worms in the poo, a chronic loose bowel (especially if it is more yellow than brown) may be an indicator that a microscopic parasite is lurking. However some amoebic parasites can trigger a more irritable bowel with a mix of loose and more constipated stools, with a fairly normal mid brown colour. Many kids with worms or another parasite will complain of a sore tummy or be very bloated much of the time. Some worms and other parasites can cause an itching in and around the anus, so if you child has their hands down the back of their pants all the time, it may be parasites. Teeth grinding, also known as bruxism, is another sign that parasites may have made a home inside your child’s gut.

There are a number of ways parasites can be picked up, from eating undercooked meat and fish, contaminated water, to household pets and from close contact with other children in the playground. Some kids are not that aware of hygiene and some find it hard to keep their hands and finger nails clean. Pica, the habit of putting non-food items in the mouth such as soil and stones, can also pose a higher risk for parasites.

Your GP can run a basic stool tests, for some of the nastier parasites, however parasites are well known to be missed by these stool tests, and this is where a more in depth private gut microbiome test organised through a nutritional therapist, naturopath or functional medicine specialist may give you more answers.

In this blog I delve into how parasites living in the intestines can disrupt the delicate balance within the gut, and also contribute to high levels of anxiety, behavioural challenges, depression and even learning delays.

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Bobby’s ‘Giardia’ story

I first met Bobby, who had just been diagnosed with autism, when he was six years old. It was a day in early December and Bobby was irritable and cranky, swearing expletives all the way through the hour and a half I spent with him. His parents described him as moody, explosive and on edge all the time. The family was at a breaking point as he could easily be violent to his younger siblings.

His parents also mentioned that he always had loose bowels and foul-smelling stools for a very long time. Knowing about the gut-brain connection, I suggested we run a stool test to see if anything untoward in his gut might be magnifying his difficult behaviour.

The most striking thing found in this stool test was the presence of a nasty microscopic parasite called Giardia, which can settle and thrive in the small intestine and does not go away on its own. I sent him straight to his doctor for treatment and by Christmas Day, he was a completely different boy. He was so much happier and relaxed; the swearing had calmed down and he could play with his siblings with no major meltdowns. We set him on a gut healing programme over the following few months and things got easier for him, making him happier and better regulated.

How prevalent are water-borne parasites?

Giardia is usually found in contaminated water, and most people associate picking it up with backpacking through remote places. For instance, I picked up Giardia when I was trekking in Nepal in my early 20s. It was truly horrid, and this was one of the triggers for my symptoms of chronic fatigue and irritable bowel back then, as well as my struggles for years to digest gluten and dairy-based foods.

However, I have seen several cases of Giardiasis over the years in which whole families have been affected by it, and they have not ever stepped out of the UK! Specifically, I have seen cases in Hampshire, Berkshire, Devon and Scotland, often when a family has their own water supply that has become contaminated.

Giardia is usually treated with a short course of antibiotics prescribed by a GP or gastroenterologist. It is harder to treat if the immune system is compromised or the infection is not picked up soon enough. Sometimes the first course is not 100 per cent effective, and the treatment needs repeating.

It can be harder to eliminate Giardia if the parasite has progressed to the cystic phase where essentially the Giardia builds a ‘crust’ or ‘cave’ around itself, so it can still act like a parasite on the host, but at the same time evade treatment by building a protective biofilm around it. This is where the acute symptoms of sulphurous ‘eggy’ burps and farts can calm down or be intermittent, but you still feel tired and cranky with changeable bowels.

Sometimes, even if the original infection is eliminated successfully, you can still experience ongoing symptoms of fatigue, an irritable bowel and difficulty digesting gluten and dairy, which can take years to go away if you don’t take things into your own hands and work on recovering the gut and any underlying deficiencies.

What about other parasites?

Giardia is just one example of a parasite that can disrupt a person’s well-being. Here are some others:

Toxoplasmosis is a condition that develops from a Toxoplasma gondii infection, which is a parasitic protozoon usually transmitted from eating raw or undercooked meat or through contact with infected cat faeces. Toxoplasma gondii has long been associated with an increase in risk taking, suicidal thoughts and schizophrenia as the brain of the host can be infected by cerebral cysts from this parasite. It may be one of the triggers for some of the more dysregulated sides to ADHD, autism and OCD as this parasite can disrupt dopamine regulation as well as interfere with the calming gamma-aminobutyric acid (GABA) pathways.
Roundworms (Ascaris lumbricoides) and Tapeworm (Taenia) can affect attention and concentration levels and appear to affect both auditory short-term memory and the scanning and retrieval of long-term memory. A roundworm infection can also pose higher risk for hyperactivity and tic disorders.
More recent research has found that certain strains of amoebic parasites that can mimic the symptoms of irritable bowel syndrome, such as Blastocystis hominis, can also disrupt executive function and working memory in adults, but I have yet to see this study replicated in children.
A waterborne microscopic parasite that causes diarrhoea, such as Cryptosporidium, if persistent and untreated is associated with impaired growth, poor physical fitness, and reduced cognitive function.
Even the humble threadworm (Enterobius vermicularis), which can cause an itchy bottom, can lead to irritability and restlessness in some children. Chronic infections have been associated with an increased risk of anxiety, depression and sleep disorders as well as deficiencies in iron and zinc. I have watched kids who have been described as ‘Horrid Henry’ (the child you would never want to invite to tea) turn into ‘Perfect Peter’ just from treating a chronic threadworm infection.

How can parasites disrupt the gut?

How exactly do these parasites wreak havoc on our children’s gut health and, subsequently, their mood and mental health? The intestinal barrier in the small intestine protects us from toxins and absorbs essential nutrients. Parasites can disrupt the integrity of this barrier, allowing harmful substances to enter the bloodstream which can, in some people, also reach the brain.

Parasites can also interfere with the production of a protein called zonulin (which can lead to temporary wheat/gluten intolerance). Zonulin can help regulate the permeability of the gut lining. This increased permeability, often referred to as “leaky gut,” can lead to inflammation and immune system activation. You can learn more about leaky gut in this blog.

Disaccharide (starch) malabsorption is common with Giardia, which can lead to fatty pale-coloured stools and an oily film which can often be spotted in the loo after doing a poo. This is the result of the gut’s inability to digest starches such as potato, rice, and pasta although it is fine with simple single sugars (monosaccharides) such as fruit and honey. Taking digestive enzymes and restricting starch intake temporarily for a few months can help some people feel better while the gut is healing.

Additionally, parasites can cause small intestinal hypermotility, speeding up food movement through the gut, which is why the child often has a loose and frequent bowel habit. This fast transit can also trigger mast cell degranulation, which is linked to an allergy-type reaction in the gut and can lead to further inflammation and discomfort.

Parasites can also affect the activity of brush border enzymes, which are essential for proper digestion and absorption of nutrients. This can result in malabsorption of important nutrients like iron and zinc, which are key nutrients that support the neurological system. Even with the best diet, without optimal absorption there may be deficiencies in these minerals, which can influence mood and cognitive function and lead to low energy and a narrowing of the diet.

The presence of parasites can also alter the composition of the gut microbiome, the ecosystem of microorganisms that live in our intestines which help to digest dairy products, dial down inflammation, support immunity and make neurotransmitters such as serotonin, GABA, dopamine and acetylcholine. Since neurodivergent kids are often sensitive to even slight imbalances in the production and synthesis of these neurotransmitters, you can see how a child can easily be derailed by disruption in the gut. This dysbiosis, or imbalance, can also lead to the overgrowth of harmful or pathogenic bacteria, further exacerbating the inflammation and nutrient malabsorption.

What is the link between mood and mind?

Most people just get symptoms such as pale-yellow stools, sulphurous gas, weight loss and exhaustion when they have a Giardia infection, and things soon clear up when the right treatment is given. However, in some sensitive adults and children it can also affect their mood and mind.

Studies have shown that people with parasitic infections, such as Giardiasis, are more likely to experience anxiety and depression, neuroticism and emotional instability. Links with poor working memory have also been cited in scientific literature. Kids with autism, tic disorders, and Tourette syndrome are also more likely to have Giardia compared with neurotypical kids.

This link isn’t just a coincidence – these parasites can trigger gut inflammation, which affects brain chemistry. Inflammation releases certain chemicals in the body, like interleukin 6 (IL6) and tumor necrosis factor (TNF), which are associated with mood disorders.

However, parasites can also affect cognitive abilities. Children infected with parasites often experience delays in growth and development, including language development and fine motor skills. These cognitive impairments can have long-lasting effects, affecting a child’s academic and social success.

Studies have also shown that children with a history of Giardia-related diarrhoea tend to have lower social and intelligence quotients. This suggests that parasitic infections extend beyond just physical health, affecting a child’s ability to interact with peers and learn effectively.

Fortunately, there is hope. Effective treatment of these parasitic infections through a doctor who can prescribe medication and working with a nutritional therapist, naturopath, or functional medicine practitioner on an ongoing gut healing programme can lead to improved physical health, cognitive function and educational achievement. By addressing the root cause of the problem – the parasites themselves – we can potentially reverse some of the adverse effects they have on kids’ mental wellbeing.

What can you do to help heal the gut?

Once you have identified that a parasite is lurking in the gut and your child has had the appropriate medical treatments required, then here are some tips to reignite the gut and help heal any damage from the recent invaders:

Add in digestive enzymes if starches, gluten and dairy products are still difficult to digest.
Heal and soothe the gut lining with slippery elm, marshmallow root and aloe vera.
Prioritise bone broths and collagen powders in the diet, as these are rich in healing glycine.
Restore the gut microbiome with live bacteria from cultured and fermented foods such as kefir, live yoghurt, miso and apple cider vinegar as well as supplementing if the diet is very limited.
Restore any losses in iron and zinc, which in turn will help the immune system, energy levels, digestion and appetite. Iron-rich foods include liver, red meat, eggs, green vegetables, pulses, prunes and apricots. Zinc-rich foods include shellfish, fish, meats, dairy, nuts and seeds. Supplements may be helpful whilst building these levels back to optimal.

Round up

Not only are gastrointestinal parasites a real nuisance, but they can also potentially influence our children’s mental health and cognitive function in significant ways, just as Giardia derailed Bobby’s life for a few years. So, if your child’s bowels and mood are always explosive, don’t just brush these off. Through understanding how these parasites disrupt the gut and affect kids’ little bodies and minds, we can better appreciate the importance of early detection and treatment.

If your child has ongoing diarrhoea, or loose stools, it is important to have a stool test carried out by your GP or paediatrician to test for the most common parasite infections. The NatureDoc clinical team can organise more in-depth parasite and gut microbiome testing if you feel you need to investigate further.

*please note that names have been changed for privacy reasons

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