The idea that diet may have a role in autism is not new, but pinpointing the effect of food choices has been challenging. A new study indicates the typical American diet may fuel autism because it is associated with mineral deficiencies, use of high fructose corn syrup, and an inability of the body to eliminate toxins.
The autism epidemic may involve dietary factors
The recent report from the Centers for Disease Control and Prevention noting that 1 in 88 children has autism spectrum disorder (ASD) has sparked a furor of concern and investigations into the prevention and causes of this developmental disorder. One angle involves the role of diet, and according to Commander (ret.) Renee Dufault of the US Public Health Service and former FDA toxicologist, that angle may include macroepigenetics.
Macroepigenetics is a scientific approach, developed by Dufault, that explores the impact of dietary factors such as high fructose corn syrup on the body and the development of chronic disorders. As the term implies, macroepigenetics involves consideration of nutritional, environmental, and genetic factors and how they work together to contribute to a specific health issue.
A person’s neurodevelopment can be negatively affected when gene expression is altered by dietary factors, such as a mineral deficiency or exposure to toxins from the environment, such as pesticides. The study’s authors explained that gene variants of paraoxonase-1 (PON1) are associated with autism in North America but not in Italy, which indicates there is regional specificity in the interactions between genes and the environment.
Therefore, in this review the investigators used the macroepigenetic approach to compare differences in diet and exposure to toxic substances between these two populations to identify factors that could be involved in the autism epidemic in the United States.
Dufault and his team concluded that, after reviewing the prevalence of autism in the United States and Italy using the Mercury Toxicity Model, that the increase in autism is not related to exposure to mercury in fish, dental amalgams, or vaccines, but to the consumption of high fructose corn syrup (HFCS).
More specifically, intake of HFCS, which is found in many commonly consumed foods in the United States, may lead to mineral imbalances involving calcium, zinc, potassium, and copper. HFCS is also a potential source of inorganic mercury.
The study’s authors noted that a combination of these mineral imbalances can create various opportunities for oxidative stress in the brain from exposure to organophosphates (extremely toxic pesticides associated with nerve damage; used on food crops and for gardens and landscaping) and heavy metals, including lead and mercury.
Consumption of HFCS and its associated exposure to inorganic mercury and fructose may alter and reduce PON1 gene expression, which can result in higher homocysteine levels, which are associated with a process that can affect neurodevelopment and the prevalence of autism.
The typical American diet and autism
Previous studies have indicated a role of nutrition in autism. A study published in Nutritional Neuroscience, for example, reported on a two-year, randomized, controlled trial of 72 children who had ASD. The children were randomly assigned to either a gluten-free diet, a casein-free diet, or no special diet.
By the end of the study, the “results suggest that dietary intervention may positively affect developmental outcome for some children diagnosed with ASD.” Other research has suggested dietary measures such as use of probiotics, as explored in a University of California, Davis, study can be beneficial.
In this latest study involving macroepigenetics, the authors noted that the typical American diet is high in HFCS, which is found in most processed foods (e.g., breakfast cereals, cookies, crackers, breads, soft drinks), and HFCS is linked to a dietary loss of zinc. The loss of zinc interferes with the body’s elimination of heavy metals such as arsenic, cadmium, and mercury, which have a negative impact on neurodevelopment.
High fructose corn syrup can also result in lower levels of calcium in the body, which can interfere with the body’s ability to eliminate organophosphates, substances that are especially toxic to the developing brain.
According to Dr. Richard Deth, a co-author of the study and professor of pharmacology at Northeastern University, “factors like nutrition and exposure to toxic chemicals are cumulative and synergistic in their potential to disrupt normal development,” suggesting the typical American diet may have a role in autism.
Critchfield JW et al. The potential role of probiotics in the management of childhood autism spectrum disorders. Gastroenterology Research Practice 2011; 161358
Dufault R et al. A macroepigenetic approach to identify factors responsible for the autism epidemic in the United States. Clinical Epigenetics 2012; 4:6
Whiteley P et al. The ScanBrit randomized, controlled, single-blind study of a gluten- and casein-free dietary intervention for children with autism spectrum disorders. Nutritional Neuroscience 2010 Apr; 13(2): 87-100
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