Department of the Senate
PO Box 6100
Parliament House
Canberra ACT 2600
‘The doctor of the future will give no medicine, but will interest his patients in the care of the human frame, in diet and the cause and prevention of disease.’
Thomas Edison
‘Let food be thy medicine.’ Hippocrates
To the committee,
I am writing to you today as an autistic person, as someone who works with people with autism and as someone who has studied Autism Spectrum Disorder (ASD) at the postgraduate level. Today I would like to draw your attention to an oft overlooked aspect of life with autism, but one which I think may be of great importance in positively affecting health outcomes and the lived experience of the autistic population in Australia.
What I would like to talk about today is diet. Diet is an important topic for autistic people for two major reasons, which are inextricably linked. Diet is a major factor in mortality for autistic people and also likely plays a very important role in the expression of symptoms of autism throughout an affected individual’s life.
Firstly, I would like to talk about something I learned when studying the epidemiology of autism. When considering the epidemiology of autism, the population is divided into two cohorts. The two cohorts are autism with and without a comorbid diagnosis of intellectual impairment. For people with an intellectual impairment life expectancy is about 40 and causes of death are typically related to diabetes, heart disease, cancer or other conditions which are strongly influenced by diet. Autistic people with intellectual impairment are also much more likely to be overweight than their neurotypical (NT) counterparts, and on average, those who are overweight are overweight by significantly more. For the segment of the autistic population who do not have intellectual impairment (a.k.a. ‘high-functioning’) average life expectancy is about 50 and the leading cause of death is suicide. In most cases the individual’s suicide is the result of chronic depression and anxiety. Recent research has shown that there is an undeniable link between the gastrointestinal tract (GI) and the brain. The link between these two organs is mediated by the diversity and robustness of the individuals microbiome. People with a healthier microbiome are less likely to experience depression and anxiety. There is also an inverse correlation between such health outcomes as diabetes, heart disease and cancer, and a healthy microbiome.
Secondly, I would like to draw your attention to an important epigenetic component of autism. Autism presented something of a puzzle to researchers, in that individuals with autism have less serotonin in their brain than an NT individual and they have more serotonin in their muscles than NTs. In case you don’t know serotonin is made in both the brain and the stomach. To make
serotonin the body needs tryptophan and Vitamin D. Tryptophan and Vitamin D are very small molecules and can cross the blood brain barrier. Serotonin is very large and can not cross that barrier. So serotonin made in the stomach stays in the body and serotonin made in the brain stays in the brain. The serotonin puzzle was solved when research realised that a gene which is responsible for pushing the building blocks of serotonin into the brain is compromised in individuals with autism. But why is this relevant? Among many other functions, serotonin in the brain is responsible for sensory gating. Sensory gating is the process by which our brains figure out what sensory inputs are most important for the conscious mind to negotiate the environment, avoid harm and gather resources; sensory gating works backwards by eliminating those sensory inputs which are not necessary. In other words serotonin helps the brain figure out what not to pay attention to. The human mind and body is an incredibly complicated and sophisticated set of instruments, which is capable of picking up many and varied signals in a wide variety of spectrums. By the time we are 5 or 6 years old our subconscious mind has figured out most of what we don’t need to pay attention to and by extension what is most important to pay attention to (being people’s facial expressions and other components of non-verbal communication). So for autistic people this ability is somewhat compromised, meaning that they may sense everything all the time. This can be very overwhelming.
Can you feel your shoes? Can you feel the tag in the back of your shirt or blouse? Do you notice the way light plays across your office at different times of the day? Or maybe the way that shadows cast by a ceiling fan create a strobing effect? Does getting a haircut feel scratchy, painful and/or overwhelming? If you have fluoro lights can you see them flickering at a rate of thousands of times a second? When you talk to people is it hard to know where to look? Do people with expressive faces sometimes look blurry to you? If you’re in a crowd does everyone’s face sometimes blend into one big confusing mess? Do you find it difficult to identify and describe what emotion/s you are feeling at any given time? If you have autism it is quite likely that you answered yes to all or most of these questions. If not, these questions might provide you with some insight into what it is like to have autism. The sensory experience of autism can be very overwhelming.
Imagine growing up and feeling everything all the time. It would make it difficult to develop ‘appropriate’ social skills. It might also result in what some people describe as unusual behaviours. Living in such a chaotic and intense world might also result in rigid and uncompromising patterns of behaviour as you attempt to impose some order on an incredibly disordered, unpredictable and overwhelming environment. A balanced diet can help the autistic individual live a better life by giving their body the building blocks to make the right amount of serotonin, in the right place at the right time.
There are two ideas I would like to propose to the committee to hopefully improve our understanding of autism and work towards better health outcomes for people with autism. The first idea is that the government should look into ways to encourage research on the links between diet and autism. The second idea is for funding for a dietitian or nutritionist to be included in an autistic individuals NDIS plan as a matter of course.
Vitamin D as I mentioned earlier is a very important factor for getting the building blocks to make serotonin across the blood brain barrier. There is a gene which uses Vitamin D to determine how much tryptophan should stay in the ‘body’ and how much should be pushed across the barrier. Evidence suggests that a gene responsible for this process is compromised in people with autism. Research has shown that maternal exposure to Vitamin D has a huge influence on the severity of a child’s symptoms if they are born with autism - in other words the less Vitamin D a mother receives when pregnant, the more severe the expression of autism. Research has also shown that Vitamin D supplementation can reduce symptoms such as anti-social behaviour, irritability and hyperactivity in individuals with autism. Most Australian’s (let alone just Australian’s with autism) don’t receive enough Vitamin D. We avoid the harsh rays of the Australian sun and the genetic damage it can cause by spending a lot of time in the shade and indoors – therefore as a nation we have a chronic Vitamin D deficiency. To further compound this problem, many people with autism spend a lot of time at home. They may have limited social opportunities, anxiety which makes it hard to leave the house or sensory issues (especially photosensitivity) that make going out a challenge – so they might not get much time in the sun. There are other ways to get Vitamin D; mushrooms, shellfish and some deep sea fish species are good sources in the absence of sunlight.
Tryptophan is an essential amino acid and is the main building block of serotonin. It is present in many foods including meat, foul, beans and oats. Many people with autism have restricted eating patterns some may not have adequate levels of tryptophan in their diet.
Now I would like to bring this discussion back causes of mortality for the autistic population. First, I should mention diabetes, cancer and heart disease. Diet and other lifestyle factors are majorly implicated in these health outcomes, especially diabetes and heart disease. As I mentioned people with autism often have restricted eating patterns and their choice of diet may directly or indirectly lead to these health outcomes. Depression and anxiety can also be influenced by diet through the effect that different foods have on the individual’s microbiome and by foods containing inflammatory factors. Foods that contain lots of inflammatory factors are typically prepackaged, processed, high-sugar, low fibre, high-carb or takeaway foods which are largely devoid of nutrition. These are the same foods that are implicated in dietary links to heart disease, cancer and diabetes. In my experience working as a support worker, these sorts of foods are almost the only things many autistic people eat (I myself have a quite healthy diet, but I am an outlier even among my NT peers). From what I have seen, a discussion of dietary influences on the severity of symptoms of autism and all causes of mortality is largely absent from the caring professions.
My life with autism has been somewhat challenging and I could probably write a book on the myriad mysteries it has presented me with, but today I have chosen to focus on health care and especially diet. I believe that one of the best ways for the Select Committee on Autism to positively affect life outcomes for autistic Australian’s is to encourage research into links between diet and autism, and for the NDIS to provide funding for a dietitian or nutritionist for people with autism. This belief stems from my research into the epidemiology of autism which showed me that most people with autism die from heart disease, cancer,
diabetes or suicide. Each of these conditions is heavily influenced by diet. Severity of symptoms of autism is strongly influenced by the genes responsible for pushing tryptophan into the brain to make serotonin and these genes need Vitamin D to do their job – both tryptophan and Vitamin D are available in abundance in a balanced diet. Research into diet and autism and funding for nutritional advice for autistic people would be two fantastic ways to ensure that autistic people in Australia are getting what they need out of their diet to live their best life and will also hopefully start a conversation that Australia really needs to have about how diet impacts the every day lives of Australians with autism.
Thank you for taking the time to read my submission and I sincerely hope it is of use to you in making determinations about how best to improve health outcomes for Australians with autism.
Yours sincerely,