Food and Behaviour Research

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Higher rates of autism and ADHD in American children may reflect poor diet and toxic exposures

by Food Ingredient and Health Research Institute

Numerous clinical trial data indicate heavy metal exposures and poor diet are the primary epigenetic factors responsible for the autism and attention deficit hyperactivity disorder epidemics.


Diagnoses of ADHD, ASD and related neurodevelopmental conditions are based on behavioural criteria, as there are no objective tests for these conditions. The features and traits that make up their core defining 'symptoms' also occur in less extreme form - as part of normal variation between individuals.

The 'causes' of these developmental conditions involve a combination of biological, psychological and socio-economic factors that will inevitably differ between individuals. 

Genetic factors clearly play a part in the predisposition to these conditions - but the genetic risks are also highly multifactorial. Furthermore, gene expression and regulation is always strongly influenced by environmental factors - a process known as 'epigenetics' - and this is particularly true in early life, when the brain and nervous system are still developing.

This new review highlights the importance of both poor nutrition and toxic exposures (particularly to 'heavy metals' such as lead, arsenic, cadmium and mercury from food and diet) as negative environmental influences on children's brain development - and their potential contributition to the increased rates of diagnosis of ASD and ADHD in the US.

For details of the underlying research, please see:

Several of our recent FAB webinars provide detailed coverage of the relevance of food, diet and nutrition to many symptoms of ADHD, ASD and related conditions, as well as practical information for parents and professionals on the management of these conditions. See 

For further news and research on these topics, see also:

27/04/2023 - Medical Xpress

In a recent study published in the
World Journal of Clinical Pediatrics, scientists led by Dr. Dufault at the Food Ingredient and Health Research Institute, reported alarming increases in the numbers of children requiring special education services.

While student enrollment in US schools remained stable from 2006-2021, the percentage of children receiving special education services increased 10.4%. Of the three disability categories under which children with autism may receive services, autism caseload percentages tripled jumping from 4% to 11% while developmental delay caseload percentages quadrupled jumping from 1% to 4%. Children qualifying for special education (SPED) services under the other health impairments category, which includes ADHD, jumped from 10% to 16%.

Dr. Dufault's research team also conducted a literature review to determine the epigenetic factors involved in the development of autism and ADHD.

Over the last ten years, numerous clinical trial data indicate dietary heavy metal exposures and poor nutrition are the primary epigenetic factors impacting gene behavior and the inheritance of autism and/or ADHD in children. Prenatal consumption of ultra-processed foods results in poor nutrition and exposures to
heavy metals which adversely impact infant gene behavior before and after birth.

The line of research that focuses on the effect of dietary factors on gene expression is known as nutritional epigenetics. Dr. Dufault's has led research efforts in this field of study since 2005 when she first identified the problem of inorganic mercury residues in high fructose corn syrup while still working at the Food and Drug Administration.

Poor diet results in dietary heavy metal exposures that over time impact gene behavior via changes in methylation patterns that impact epigenetic inheritance. 

Heavy metal residues continue to be a problem in the food supply. The US Congress released two reports in 2021 on the problem of heavy metals in baby foods. The first report issued on February 4, 2021, revealed baby foods are tainted with dangerous levels of arsenic, lead, cadmium, and mercury. The second report, issued on September 29, 2021, confirmed new disclosures from manufacturers show dangerous levels of heavy metals in even more baby foods. These heavy metal exposures may further exacerbate the development of autism and ADHD.