A lot of people with Autism/ADHD have sensitivity issues which can affect their physical health, mental health, body functions, and quality of life. This is quite a common finding I see in clinical practice. Sometimes health issues like sensitivities can have a very simple explanation and a very simple solution!

A sensitivity, as the name suggests, is related to your senses, such as of smell and taste, and more. People often refer the sensitivities as “intolerances” which is not the same thing. The sensitivities result from internal reactions to external sources, through our senses.

People with Autism/ADHD and related conditions can often have sensitivities to:

- Sight, including of sunlight and bright light – causing watery eyes, irritation, headaches and migraines, and the need to wear sunglasses, which causes even more health issues (but that’s a topic for another article!)
- Smells – of strong smells causing irritation, runny nose, headaches and migraines, and nausea or even vomiting (including morning sickness!)
- Sounds – loud noises causing shock and stress, ear pain, tinnitus (annoying ringing in the ears) and more
- Touch – of physical touching, or irritation to different fabrics, materials and surfaces, tight-fitting clothes, and tags on clothes, shoes etc
- Taste – changes in the taste of foods, of either no taste, or being repulsed by the taste of foods, and even the feeling of textures of foods can be off-putting and causing food restrictions (and nutrient deficiencies)
- Alcohol – having a stronger and quicker response to alcohol than others
- Medications - having a stronger and quicker response to some medications than others
- Emotional sensitivities – responding quickly and excessively to even minor stresses or emotions.

This is why I always ask questions about sensitivity issues in my initial consultations with patients! The more and stronger the sensitivities there are in someone, it gives me big clues as to what might be causing their sensitivities and other symptoms too.

Sensitivities are much more prevalent and severe in people with ASD and ADHD, and often affecting more than one of their senses. Typical sensitivities in ASD/ADHD include being sensitive to the sun or light (and preferring to be in the dark), a poor sense of taste and smell, or hyper-reacting to tastes and smells, sensitive to loud or sudden noises such as in schools or shopping centres, food texture issues preventing eating of many foods, and other reactions.

The over-stimulation of the senses bombards the nerves and the nervous system (Attitude Mag, 2025). This in turn causes so much information being sent to the brain and overloads it, causing an inability to concentrate or focus on important tasks, the person becoming overwhelmed quickly, and having an initial feeling of plenty of energy (seen as hyperactivity) but burning out quickly to fatigue. Combine this hyperstimulation with an inability to calm, and you have many of the characteristics of ASD/ADHD!

The sensory overload to the brain can also contribute to the inability to calm the brain and nervous system, and can often be diagnosed as Sensory Processing Disorder, another common co-morbid diagnosis in many people with Autism/ADHD.

It's not particularly well known that ONE major nutrient deficiency can affect all our senses! This nutrient deficiency can cause dysfunction in our senses, from reduced function to hypersensitivity.

That nutrient deficiency is the essential mineral of zinc!

Of course, zinc isn’t the only nutrient deficiency in ASD/ADHD, but it is extremely common in these conditions, and it has a huge impact on ASD/ADHD symptoms. For example, a zinc deficiency can cause other Autism/ADHD symptoms including:

1. Affecting stomach function – to cause reduced digestion. And leading to reduced nutrient absorption and other nutrient deficiencies. This can also lead to digestive symptoms of reflux, indigestion, heartburn, gas, bloating, and constipation or diarrhoea
2. Anaemia and iron deficiency – zinc is needed for protein metabolism and iron metabolism. Anaemia is extremely common in those with ASD/ADHD in approximately 80% of cases in my experience
3. Neurotransmitter and hormone imbalances – zinc is needed to make the neurotransmitters and other hormones too, therefore low zinc can affect moods and behaviours and mental health
4. Sleep issues – zinc is needed to make melatonin, the sleep hormone, hence a zinc deficiency can affect sleep
5. Skin issues and joint issues– zinc is needed for skin and connective tissue with collagen production. Low zinc can cause poor skin integrity, rashes and lesions, growing pains, hypermobile joints, all common with ASD/ADHD
6. Low immune system function – zinc is needed for production of the white blood cells for your immune system and protection from infections. Low zinc causes reduced immunity and increased or more frequent infections
7. Thyroid function – zinc is needed for optimal thyroid function and to make the thyroid hormones which control your whole body’s metabolic rate and all organ and cell functions. It’s very common to see many people with ASD/ADHD with low functioning thyroid, and this causing a lot of their symptoms.

​Correcting a zinc deficiency can therefore reduce all of these issues, and give other benefits to your health too, and can greatly reduce the Autism/ADHD symptoms.

This should be the biggest shock to people with Autism/ADHD or parents of children with these conditions. Or one of the biggest omissions in testing or treatment for people and children with Autism/ADHD.

But you can’t or shouldn’t just go out and get some zinc if you have ASD or ADHD! You need to get this tested first, along with other blood tests which are related to low zinc levels, such as checking for anaemia and immune function, iron levels, thyroid function, stomach function, and more. This will help with getting a baseline of your zinc levels to check against later, as well as helping with your likely dosing needs.

There are also some tricks with taking zinc, such as the therapeutic doses, the forms or types of zinc (ie zinc oxide, zinc picolinate, zinc citrate, zinc amino acid chelate, or others) and/or from foods, as some of these forms are useless and not bio-available, and some are much better! The timing and dosing of the zinc is very important to reduce possible side effects.

This is where I can help, with recommending specific testing first, and dietary improvements, and improving digestive system function, and recommending the right form of zinc and dosing for each person.
More more info on this website, including the Bookings page, where I can help you in your journey to reducing your symptoms and improving your health!

References:
Attitude Mag. (2025). My Hypersensitivity Is Real: Why Highly Sensitive People Have ADHD. Retrieved 5th November 2025 from

Part 1 of Autism/ADHD and MTHFR:

On the genetics topic again with Autism and ADHD, to explain why these conditions are mostly nothing to do with them being caused by genetics, and why there are always other factors which cause Autism/ADHD or contribute to their presentation and symptoms.

You may or may not have heard of the MTHFR gene. This is an acronym for Methylene Tetra Hydro Folate Reductase, which is a gene we all have, and in turn produces a protein/enzyme in the body, also called MTHFR. This enzyme is needed for the metabolism of folate (vitamin B9) from its inactive form in foods into the active form of folate, called methylfolate, so your body can use it.

A large percentage of the population, approximately 40%, have a variant to one or both of the main types of MTHFR genes. This is NOT a genetic mutation at all, as mutations are changes to genes being different to what your parents had, or a genetic change within your lifetime, typically due to viruses, chemical toxicities, or radiation. A genetic variant is often a historical change or difference to a gene which is not “normal”, usually due to a single DNA building block/protein being replaced by another. These variants can be passed onto children and their children.

Two of the main MTHFR gene variants occur to the MTHFR C677T and A1298C genes.

The MTHFR genes are also related to energy production, genetic expression, production of neurotransmitters for good mental health balance, and detoxification. Hence any variant to the MTHFR genes can have a minor, moderate or even a severe impact on these body functions. All of these functions are typically compromised in people with Autism/ADHD.

But why are Autism/ADHD conditions not genetic, if they can be related to genetic variants to the MTHFR genes?!

Because of epigenetics. This is the science of how your environmental factors can interact with your genes to turn them on or turn them off to contribute to your health or to cause disease symptoms and conditions. Hence you may have a genetic predisposition to certain symptoms or health issues, but only if triggered by your epigenetic/environmental factors. These include stress, toxicities, poor sleep, nutrient deficiencies, inflammation and oxidative damage, and more. Or if you do all the right things and reduce these factors, even though you might have the genetic variants and their predisposition to symptoms, you can effectively turn off the genetic variants and reduce or eliminate your risk of their related symptoms and conditions.

Hence your epigenetic/environmental factors are far more responsible for your health (or your symptoms and conditions) than your genetics alone! This is why Autism/ADHD is not normal at all, not caused by genetics alone, and why when the epigenetic/environmental factors or triggers are reduced, avoided or fixed, the symptoms and conditions of Autism/ADHD can reduce, or be cleared and reversed.

You can test for your MTHFR status with a genetic test, which reports on whether you have none, one or both variants of the MTHFR gene, and also whether you have one or both copies of the variation from both your parents. However, there are limitations to getting the MTHFR genetic test, with one being that it’s not the only test which is needed to be done to find the causes or results of the MTHFR variant contributing to your health issues. The tests needed can differ from person to person, depending on your symptoms and conditions. However, this is something that I can help you with.

See my follow up this article on this topic, with part 2 on issues with the MTHFR variants and Autism/ADHD.

This is Part 2 of my article on MTHFR and Autism/ADHD:
​
This article follows on from my previous article on the MTHFR gene and its relationship to Autism and ADHD conditions.

Many published studies show the links between having the MTHFR genetic variants and Autism/ADHD symptoms and conditions, for a number of reasons:

1. Having an MTHFR variant can cause a functional deficiency of folate, which in turn can affect the metabolism of other vitamins such as B12, B6 and others, thus potentially causing a number of nutrient deficiencies and their related deficiency symptoms
2. MTHFR metabolic issues can affect energy levels, to cause weakness, fatigue, brain fog, poor memory and concentration, which are common in Autism/ADHD
3. MTHFR issues affect the production of hormones and neurotransmitters, to cause mood and behaviour changes, and other mental health symptoms such as depression, anxiety, anger and violence and more
4. MTHFR variants can affect detoxification functions, and causing increased toxicity, which can affect brain function to affect moods and behaviours and mental health
5. MTHFR variants reduce the ability of the body to metabolise homocysteine, resulting in increased inflammation and oxidative stress in the body, which in turn affects moods and behaviours and mental health
6. Some MTHFR variants, specifically the C677T variant, are associated with the increased risk of Autism disorders, Bipolar Disorder and Schizophrenia (Li et. al., 2020; Meng et. al., 2022), being serious neurological disorders which are commonly seen along with Autism/ADHD
7. The MTHFR A1298C variant is also related to Bipolar Disorder and ADHD, but not Autism disorders
8. Some MTHFR variants can increase the risks of, or worsen, heart and circulation issues.

Studies show that there is a link to having the MTHFR variants with these neurodevelopmental and neurological conditions, which includes Autism and ADHD, and therefore related to the metabolism of folate (and vitamin B12, B6 and others) (Meng et. al., 2022). Folate from foods, which the MTHFR gene metabolises, is needed for the development and function of the nervous system and the brain, hence the importance of your foods and nutrition for preventing and even treating Autism/ADHD! Or on the other hand, poor food choices and nutrient deficiencies can contribute to mental health symptoms and Autism/ADHD. Folate is particularly needed for DNA replication when cells divide and create new cells during periods of growth and development, especially in pregnancy for a foetus, or in the growing childhood years.

Sadly a common recommendation from doctors is for women who are trying to conceive, or pregnant women, to take high doses of folic acid to prevent neural tube defects such as spina bifida, without actually checking the MTHFR genetic status of the woman first. Folic acid is NOT the same as folate from foods!

Folic acid is the synthetic form of folate in all non-organic wheat flour based products, processed foods, and in cheap (and nasty) supplements. Metabolising folic acid in the body is a much slower process than from natural folate in foods, which can create a deficiency of methylfolate (the active form the body uses) when it’s needed. If you have any of the MTHFR genetic variants, this will compound the problem of metabolising folic acid (and natural folate), to further slow down the body’s use of methylfolate, creating more of an issue of a deficiency of methylfolate, and leading to its related symptoms. Even worse, is that folic acid from wheat flour products, processed foods and supplements, can actually BLOCK the folate receptors on the cells, to even further slow down the ability of cells to use the methylfolate. Hence folic acid can make MTHFR related symptoms and conditions MUCH worse, including in those with Autism/ADHD and related other conditions.

But what do children and people with Autism/ADHD like to eat?! Lots and lots of beige foods of breads, bakery products, pasta, cereals, wheat flour crumbed chicken nuggets, and processed foods – ALL very high in folic acid! And you wonder why they have mood and behaviour issues, mental health symptoms, and Autism/ADHD.

Folic acid isn’t just a problem in children or people with MTHFR genetic variants, or with Autism/ADHD. Folic acid still slows down the metabolism of natural folate in everyone, but having an MTHFR issue makes it several times worse.

Folic acid must really be avoided by everyone!

There are, of course, other causative factors to Autism/ADHD conditions than someone’s MTHFR status. But having an MTHFR variant can contribute in many ways to the mood and behaviour issues and other symptoms of Autism/ADHD.

Stay healthy!

References:

Li, Y., Qiu, S., Shi, J., Guo, Y., Li, Z., Cheng, Y., & Liu, Y. (2020). Association between MTHFR C677T/A1298C and susceptibility to autism spectrum disorders: a meta-analysis. BMC Pediatrics, 20, 449. DOI: 10.1186/s12887-020-02330-3

Meng, X., Zheng, J. L., Sun, M. L., Lai, H. Y., Wang, B. J., Yao, J., & Wang, H. (2022). Association between MTHFR (677C>T and 1298A>C) polymorphisms and psychiatric disorder: A meta-analysis. PloS one, 17 (7), e0271170. DOI: 10.1371/journal.pone.0271170