What does gut health have to do with Autism Spectrum Disorder?

Georgie Stephen Children's Health, Digestive Health, Mental Health Leave a Comment

The diagnosis of Autism Spectrum Disorder (ASD) is rapidly increasing, with recent Australian numbers revealing a 79% increase in the number of people diagnosed with ASD between 2009 and 2012 alone. In the US, 1 in 59 children have a diagnosis of ASD.

With the current lack of pharmaceutical medications available to treat the core symptoms ASD and no known cure, many families and parents are left wanting for additional support options. In fact, as many as over half of parents with ASD children have tried some form of complementary and alternative medicine in an effort to reduce ASD behaviours and improve their child’s quality of life.

Fortunately, thanks to emerging research in recent years, our understanding of the causes and drivers of ASD has significantly expanded, revealing new and more targeted possibilities for supportive therapies for families and children with ASD.


ASD – a genetic disorder or something more?

In the past, ASD was accepted as a purely genetic condition that was predetermined at or even before birth. It was thought that genetics alone were responsible for the impaired development of certain brain areas related to social-emotional development, for example, the amygdala. While genetics unquestionably play a large role in a child’s susceptibility for developing ASD, contemporary understanding now points to a complex interplay between large number of genetic, environmental, and individual health factors that result in a disorder that is body wide but which predominately affects the brain (see figure 1).

In addition to the obvious involvement of the nervous system, the other major body systems that play a role in ASD include the immune system, the digestive system, and the liver and detoxification system


The immune system and neuroinflammation

Inflammation of the brain and nervous system, referred to as neuroinflammation, is a key feature of ASD (see here  and here). It develops when the perfect storm of factors comes together in a predisposed child (figure 2) – a child with a certain genetic predispositions, when exposed to one or more triggering factors may develop neuroinflammation. Then, if other aspects of the child’s overall health are also compromised, the neuroinflammation is unable to be controlled and continues long term (chronic neuroinflammation), resulting in negative impacts on brain development, changes neurotransmitter production and communication pathways, and impairs nervous system tissue repair.


The key to addressing chronic neuroinflammation and the immune system dysregulation that causes it is identifying and controlling the initial and perpetuating triggers for the inflammatory response, which may be one or more of the following:

·      Serious infections

·      Environmental exposure to chemicals or toxins

·      Food allergies or intolerances

·      Nutritional deficiencies

·      Surgeries or other physical traumas

·       Chronic stress or other emotional traumas

·      Dysbiosis

·      Leaky gut

·      Poor diet

·      Poor digestion and breakdown of food


The digestive system and the gut-brain connection

The gut and brain are connected via a communication highway known as the gut-brain axis . The line of communication is bidirectional whereby the gut can send messages to and influence the brain and vice versa.

The gut communicates via chemical messengers (for example, hormones and neurotransmitters), bacteria or bacterial byproducts (originating in our microbiome), and immune cells, while the nervous system directly innervates the gut via the vagal nerve and sends chemical messages in the form of neurotransmitters.

Therefore, if gut health is an issue, this can have a significant impact on nervous system and brain function.


The microbiome

Our gut is home to a large population of bacteria known as the microbiome. This ecosystem of beneficial bacteria is responsible for an impressive range of physiological functions, including immune system regulation and nervous system activity. If our microbiome becomes unbalanced, something known as dysbiosis, this can trigger a cascade of negative outcomes that can contribute to the development of ASD in predisposed children.

In infants and young children, the microbiome significantly influences the development of the immune system and contributes to neurodevelopment via the gut-brain axis. Dysbiosis is often seen in children with ASD, and the presence of dysbiosis and severity of other digestive symptoms has been associated with severity of ASD symptoms. Novel new treatment studies have observed that when dysbiosis is addressed, ASD symptom severity reduces, as was seen in a recent study using fecal microbial transplant. These findings highlight the close relationship between the gut, the microbiome, and the brain in ASD.

Dysbiosis also creates an inflammatory state in the digestive system, sends inflammatory signals to the brain that perpetuate neuroinflammation, and can potentially lead to leaky gut over time.

Factors that can contribute to the development of dysbiosis can accumulate over a child’s lifetime and may even begin before birth with the health of the mother, including:

·      A diet low in fibre, whole foods, and fruit and vegetables

·      A diets high in processed and refined foods

·      Repeated use of antibiotics

·      The type of feeding during infancy – particularly formula feeding

·      The type of delivery at birth – particularly caesarian section deliveries

·      The timing of solid food introduction in early life

·      The home environment and family structure (number of siblings, pets in the house)

·      Infections, particularly in early life

·      Maternal dysbiosis during pregnancy

·      Maternal diet during pregnancy


Leaky gut

A well functioning, robust digestive system is acts as a buffer between our internal body and the outside world. Normally, the cells lining our digestive tract exert strict control over what is transported across cell membranes and into the blood, keeping unwanted substances out of the body and shuffled along to be eliminated with our stool as a waste.

Unfortunately, the integrity of our gut lining can be compromised. This leads to increased permeability of the gut (aka leaky gut) and the unregulated movement of food particles and other substances into the body. The immune system recognises these substances (food, bacteria, or chemical) as foreign invaders and mounts an immune response against them. Over time, with chronic leaky gut and immune activation, the immune system can become overwhelmed or fatigued and ultimately ends up in a dysregulated state.

The following factors may contribute the development of a leaky gut over time:

·      Poor digestion and breakdown of food

·      Food allergies or intolerances

·      A diet low in fresh, whole foods, particularly fruits and vegetables

·      A diet high in refined and processed foods, particularly those foods with additives

·      Dysbiosis

·      Gut infections, for example, with pathogenic bacteria, parasites or yeasts

·      High levels of stress and anxiety

·      Impaired sleep


The role of diet and food

Diet plays a significant role in gut health and immune system regulation. The food we eat either supports or starves our microbiome and is a huge factor involved in the development of dysbiosis, and consequently, leaky gut, both of which contribute to immune system activation, inflammation, and eventually, immune dysregulation.

To add, food intolerances and allergies are seen at higher rates in children with ASD (see here and here). Reactions to food can contribute to local digestive dysfunction (including dysbiosis and leaky gut) and system wide immune activation.

The most common food allergies or intolerances in children with ASD include:

·      Gluten

·      Casein (a protein found in dairy foods)

·      Soy

·      Histamines

·      Oxalates

·      High intake of refined sugar, especially in those children with concurrent ADHD

·      Sensitivities to food additives (flavours, colours, preservatives, etc.)

As dietary changes can be incredibly challenging in children with ASD who may be picky eaters or who may already have a restricted diet, the best approach is to consult with a qualified health professional well versed in nutrition for guidance about the most well indicated diet changes for your child based on their individual health. This ensures the best use of your time and energy in making difficult dietary changes.


The liver and detoxification system

Our liver works hard day and night to manage chemical load in the body. From the food we eat, to the hormones and neurotransmitters our body produces, to the chemicals we are exposed to in the environment on a daily basis, the liver is constantly detoxifying the good and the bad to keep our body in homeostasis. If the liver can’t keep up with the demands being placed on it, chemical load can increase and countless body systems begin to suffer.

Liver function and detox pathways can slow down when the required nutritional tools for optimal function are deficient, for example, amino acids from protein, zinc, selenium, B-vitamins, magnesium, or vitamin C, amongst others.

To add, chemical load can become so high from repeated exposure in the environment or from food that the liver simply can’t keep up with the demand, no matter how robustly it is working.

Chemicals or other substances in the body that remain unprocessed by the liver, for whatever reason, can become a trigger for inflammation, immune system dysregulation, oxidative stress, and tissue damage. Depending on the chemical, some are able to cross into the brain and directly contribute to neuroinflammation.

Undesirable chemicals may include:

·      Food additives – preservatives, colourings, flavourings, etc.

·      Heavy metals like mercury, lead, arsenic, or cadmium

·      Plastic goods, including packaging, toys, furniture, house fixings, and other household items

·      Compounds found in from cigarette smoke, exhaust fumes, or charred meats

·      Cosmetic chemicals in conventional personal care products like shampoos and soaps

·      Cleaning agents found in household cleaning products like sprays and detergents


Understanding and supporting whole body health in ASD

Taking into consideration the complex interplay of the systems and factors discussed above, the following steps can be taken to start supporting your child with ASD today:

1.    Understand the predisposing factors that created the right environment for ASD to develop and support them accordingly

2.    Reduce inflammation

3.    Investigate gut health and restore balance to the microbiome

4.    Identify and remove allergens and intolerances

5.    Reduce chemical load and support liver detoxification pathways

6.    Build strength and resilience of relevant systems using food, nutrients, and herbs

7.    Promote healthy diet patterns by addressing picky eating and building food variety

With this new whole body view of ASD, the possibilities for support and intervention open up dramatically. A natural medicine approach that seeks to identify underlying causes, support body systems in a holistic way, and build physiological strength and resilience with herbs, nutrients, and food offers an exciting world of possibility for the many families and parents of children with ASD looking for more ways to support their child.



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