Anxiety is the most common symptom experienced by a vast percentage of children and adults with autism

Featured article in the Autism Eye magazine. Written by Stella Chadwick.

Anxiety is the most common symptom experienced by a vast percentage of children and adults with autism. Anxiety disorders can manifest as persistent, excessive worry about everyday things, or anxiety and fear in social situations.

There can also be irrational fear of things and many can have unwanted and intrusive thoughts, compelling them to formulate coping mechanism through rituals. In this article, we explore the potential biochemical causes of anxiety and explore strategies to reduce and manage the symptoms.


There is no “catch-all” diet that can work in relieving anxiety, but generally, reducing sugar and removing gluten (wheat, barley and rye), dairy, soy, artificial colours and preservatives, and in some cases, corn, can significantly reduce anxiety levels.

Some can get exceptional relief from anxiety by removing grains, synthetic sugars and starches altogether, following the Gut and Psychology Syndrome (GAPS) diet or the Specific Carbohydrate Diet (SCD). Reducing foods high in glutamate, an excitatory neurotransmitter, which can damage nerves (see Table 1), can also have a significant impact on reducing anxiety.

See Table 2 for the key signs and symptoms attributed to food sensitivities.


Studies have shown that the bacteria living in the gut can alter the way the brain works. By changing the gut ecosystem scientists have shown that they can turn mice with anxiety into mice that are confident and bold and mice that are shy into social mice. Rats inoculated with bacteria from depressed people have been shown to develop signs of depression themselves.

In human studies, specific kinds of bacteria such as lactobacillus reuteri have been shown to have the ability to change brain activity and ease anxiety. Pre-biotics such as Bimuno developed by Reading University also show great promise in helping reduce anxiety, by naturally feeding and increasing the friendly bacteria in the gut.

Table 3 shows the effect of bacteria on neurotransmitters.


PANS (Paediatric Acute-Onset Neuropsychiatric Syndrome), triggered by infections such as the flu, chickenpox, mycoplasma, lyme disease, etc.), and PANDAS (Paediatric Autoimmune Neuropsychiatric Disorders Associated with the Streptococcal infection) triggered by the streptococcal bacteria can cause autoimmunity where the brain becomes the target of attack.

In almost all cases children develop OCD, uncontrollable rage and extreme anxiety and in some cases, they also develop vocal or motor tics. Medical intervention through the use of antibiotics, antivirals and, in some extreme cases, immunoglobulin therapy may be necessary but in all cases, there needs to be a holistic approach to removing the infection, and building and balancing the immune system.


There are specific brain chemicals called neurotransmitters which send signals throughout the central nervous system. Eating a low allergenic diet rich in nutrients, and including adequate amounts of good quality protein (such as meat, eggs, chicken, fish, pulses and beans), are the best ways to balance brain chemistry.

However, sometimes a little extra help is required. Gamma-amino butyric acid (GABA) is our key calming neurotransmitter, significant for speech. Reishi mushrooms, broad beans, tomatoes, sunflower seeds and fermented drinks and foods (especially sauerkraut), contain naturally occurring GABA. Supplements containing GABA are not readily available over the counter in the UK.

GABA production can be promoted with adequate levels of taurine – an amino acid available as a supplement, and vitamin B6 as well as compounds such as L-theanine; a plant-based chemical found abundantly in green tea, inositol; a B group vitamin, found in cantaloupe and oranges, magnesium found in spinach, pumpkin seeds, and avocados, and glycine found in in fish meat, spinach, cauliflower, bananas and cucumber. Herbs such as passiflora, skullcap, lemon balm, magnolia bark have also been shown to increase levels of GABA.

Table 4 outlines the key symptoms suggestive of low GABA levels.

Disturbed serotonin production is common in autism. Serotonin is our feel-good neurotransmitter and the precursor to melatonin, our sleep hormone. 95% of serotonin is produced in the gut and healing and repairing the gut lining and populating it with a broad range of bacteria, controlling yeast and clearing out parasites are key to balancing the levels of this neurotransmitter.

In some cases, supplementing with tryptophan, the starting amino acid for the synthesis of serotonin, can ease anxiety by promoting serotonin production. In some cases, it is more helpful to use 5-HTP – the intermediary between tryptophan and serotonin.

Table 5 outlines the key symptoms suggestive of low serotonin levels.

An impaired adrenal function is also common in autism. Catecholamines, such as adrenaline and noradrenaline as well as dopamine are produced and used in the fight-or-flight response. In many cases, especially where there are significant sensory processing difficulties, the body can be under continued stress leading to the disruption of these hormones.

In some cases supplementing with tyrosine, an amino acid and a precursor to catecholamines can provide significant relief from anxiety. Omega 3 fatty acids, as well as vitamin D, also play key roles in supporting catecholamine production. Table 6 outlines a list of the key symptoms suggestive of the need for catecholamine support.


This is a disorder where excessive production of pyrroles ( a key component in haem), results in significant zinc and vitamin B6 deficiency leading to a host of symptoms, including anxiety. Over 90% of those with high levels of anxiety, depression, ADHD have low blood levels of zinc, and find relief through adequate supplementation.

Supplementing with vitamin B6 has also been shown to reduce anxiety. Vitamin B6 is essential for the synthesis of serotonin, dopamine and GABA, three critically important neurotransmitters. Low levels have been associated with irritability, depression, and problems with speech.

(Read more in our blog post – Could it be KPU?)


This is a biochemical process, which occurs trillions of times a day and contributes to a large number of processes in the body, determining how we respond to our environmental stressors, how we detoxify and how we build new DNA. In the majority of cases, those on the spectrum tend to be under-methylators, which can lead to high levels of anxiety.

Using supplements such as methyl-folate, folinic acid, B12, P5P, methionine, SAMe (not available as an over the counter supplement in the UK), it is possible to improve methylation.


Excessive and persistent levels of anxiety can be debilitating, impacting health on a fundamental level. Reducing allergenic load is key to alleviating symptoms, as well as healing and sealing the gut and removing persistent infections.

Additionally, it is imperative to ensure that disorders such as KPU are identified and supported and that methylation is optimized. Using certain supplements judiciously to support neurotransmitter balance can also bring significant relief.


TABLE 1: Foods That Can Damage Nerves

  • Anything enzyme modified
  • Anything protein fortified
  • Anything ultra-pasteurized
  • Anything vitamin enriched
  • Anything with corn syrup added
  • Anything with milk solids
  • Baked goods from bakeries
  • Barbeque sauce
  • Bottled spaghetti sauce
  • Boullion (any kind)
  • Canned and smoked tuna, oysters, clams
  • Most Canned soups, Canned refried beans, Caramel flavouring/colouring
  • Cereals
  • Chilli sauce
  • Chocolates
  • Citric acid (when processed from corn)
  • Corn-starch
  • Corn chips (most brands)
  • Dough conditioners
  • Dry milk or whey powder
  • Egg substitutes
  • Flavoured crisps
  • Flavoured teas, sodas
  • Flowing agents
  • Fresh and frozen pizza
  • Fried chicken from fast food sources
  • Icing and fillings
  • Gelatine
  • Gravy Master
  • Instant soup mixes/Stocks
  • Kombu extract
  • L-cysteine
  • Low-fat/Diet foods
  • Many salad dressings/Croutons
  • Mayonnaise
  • Molasses
  • Most salty, powdered dry food mixes
  • Mustards
  • Non-dairy creamers
  • Parmesan cheese
  • Pectin
  • Pickles
  • Salted peanuts (certain brands)
  • Powdered soup and sauce mixes 
(certain brands)
  • Processed cheese spread
  • Ramen noodles
  • Sausages/Processed meats/Cold cuts

Source: Autism: Pathway To Recovery, by Amy Yasko, PhD

TABLE 2: Food Sensitivity Questionnaire – Signs and Symptoms

  • Anxiety, fear, panic attacks, social phobia
  • Depression
  • Excessive daily mood swings or bipolar disorder
  • Preferring to eat certain foods daily, such as bread, pasta, cheese, or ice cream
  • Fatigue or drowsiness, especially after eating
  • Asthmas, congestion, postnasal drip, or hay fever
  • Sensitivity to food dyes and additives, showing up in symptoms such as rashes or headaches
  • Insomnia
  • Digestive problem like gas, bloating, constipation, or diarrhoea
  • Migraines and chronic headaches – in non-verbal children this may translate into head
  • banging
  • Rashes, eczema, dermatitis, or psoriasis
  • Frequent colds and infections

If you tick more than 5 in this section it is likely that food sensitivity is playing a part in inducing anxiety.

Source: The anti-anxiety food solution Book by Trudy Scott, CN

TABLE 3: Bacteria that Make Brain Chemicals:

Table - Bacteria that Make Brain Chemicals

Source: T.G. Dinan et al/J. Psych. Res. 2015

TABLE 4: Low GABA Questionnaire – Signs and Symptoms

  • Anxiety and feeling overwhelmed or stressed
  • Panic attacks
  • Unable to relax
  • Stiff or tense muscles
  • Feeling stressed and burnt-out
  • Craving carbohydrate-rich foods

If you tick more than 3 symptoms, anxiety can be the result of low GABA

Source: The anti-anxiety food solution Book by Trudy Scott, CN

TABLE 5: Low serotonin Questionnaire – Signs and Symptoms

  • Anxiety
  • Panic attacks or phobias
  • Feeling worried or fearful
  • Obsessive thoughts or behaviours
  • Perfectionism and being overly controlling
  • Irritability
  • Anxiety that’s worse in winter
  • Winter blues
  • Negativity or depression
  • Suicidal thoughts
  • Excessive self-criticism
  • Low self-esteem
  • Poor self-confidence
  • PMS
  • Sensitivity to hot weather
  • Hyperactivity
  • Anger or rage
  • Digestive issues
  • Joint pains
  • Difficulty sleeping before 10 PM
  • Insomnia or disturbed sleep
  • Afternoon or evening cravings for carbohydrates

If you tick more than 6 symptoms, supporting serotonin levels may be helpful.

Source: The anti-anxiety food solution Book by Trudy Scott, CN

TABLE 6: Low Catecholamines Questionnaire – Signs and Symptoms

  • Depression
  • Easily bored
  • Lack of energy
  • Lack of focus
  • Lack of drive and low motivation
  • Attention deficit disorder
  • Procrastination and indecisiveness
  • Craving carbohydrate-rich foods

If you tick more than 3 symptoms, supporting catecholamine levels may be helpful

Source: The anti-anxiety food solution Book by Trudy Scott, CN