Breaking down the science: Common questions and answers about exploring links between food and autism

On April 12, IATP staffer Dr. David Wallinga co-published a study online that explores the links between food and autism.

The paper proposes a macroepigenetic model as one scientific approach that allows us as researchers to consider multiple factors, including nutrition and environmental exposure to toxins, and how they can impact our health. Because this is a new approach, we’ve prepared a brief Q & A we hope will address many potential questions.

Q: What causes autism?

A: There is no one cause of autism. Multiple factors in our food and broader environment combine with inherited factors to contribute to autism. All of these factors can play different roles, and can take on various levels of significance in different individuals—all of us are unique in our susceptibility to diseases and disorders, like autism.

In the real world, we are exposed to a complex equation of factors that can ultimately influence our health. As Harvard pediatric neurologist Martha Herbert, M.D. puts it, there is an important difference between “cause” and “risk.” It isn’t even appropriate to talk about a “cause” of autism. Instead, it is more fitting to talk about multiple, interactive risks in our broader environment that may accumulate and contribute to autism. In any child these environmental factors have the potential to modify the genetic susceptibility she or he is born with.

Q: Does consumption of HFCS cause autism?

A: HFCS consumption in and of itself does not cause autism, but this study finds that it may be a risk factor that can contribute to the development of an autism spectrum disorder. Current science indicates that a number of factors likely combine to cause or contribute to the development of autism, including nutrition and other environmental factors, as well as inherited factors.

This study lays out an evidence-based model of how consumption of high fructose corn syrup can impact mineral balance in the body, and subsequently the body’s ability to eliminate toxic chemicals which may contribute to a higher incidence of autism.

Further study on environmental and dietary risk factors for autism is still needed. Because there is no one single cause of autism, we need to invest in research that helps us understand the complex interactions that happen in our world and can cumulatively contribute to the eventual development of autism. HFCS is one potential risk factor that the authors chose to study, but it is certainly not the only risk factor.

Q: How are mineral deficiencies related to autism? 

A: Diets deficient in some minerals, like calcium, can increase the absorption of toxins like lead in a person’s environment, or impair the metabolic processes required to eliminate organophosphate pesticides. Diets deficient in other minerals like selenium, a potent antioxidant, leave the body impaired in its ability to repair the damage to DNA that accrues from living in a polluted environment and consuming mercury and other food contaminants. Diets deficient in zinc can disrupt heavy metal metabolism and excretion.

Q: How does HFCS affect levels of minerals like zinc in the body?

A: In humans, HFCS consumption has been shown to impact the body’s ability to manage the proper balance of certain beneficial minerals in the body. It can lead to zinc loss and copper gain, for example. With the depletion of zinc, the body’s immune system can be compromised and this is when disease takes place. In the case of autism, with zinc insufficiency, the child’s body is unable to correctly produce the protein required to transport and release toxic metals such as mercury and cadmium from the body. Hence, some children with autism tend to accumulate these heavy metals.

HFCS consumption can lead to lower calcium and phosphorus in the body as well. Additionally, when dietary intake of magnesium is low, additional calcium losses can occur with HFCS consumption.

With the depletion of calcium, the body’s immune system is again compromised because the process of producing a key enzyme required for organophosphate metabolism and excretion is impeded.

Q. How are HFCS consumption and mineral levels related to genes?

A. Genes, which are inherited, contain coded information that constitutes the potential instruction book for the function of cells, and therefore the body as a whole. However, the environment surrounding genes—the epigenome—determines whether or when that instruction book gets opened. In other words, the environment determines how or when genes get turned on or off, or “expressed.” 

This study coins the term “macroepigenetics” to describe a model for thinking about how a range of environmental factors, including both toxic chemicals, mineral deficiencies and other nutritional factors, combine to affect gene expression.

Q. How should one weigh the effects of genetic and environmental factors when it comes to autism?

A. While a person’s genes may determine whether they carry the potential to develop autism, the model described in the study suggests that environmental and dietary factors can play a key role in determining whether an individual acquires the traits that we describe as autism.

Q: What is HFCS?

A: High fructose corn syrup is considered a sugar substitute. It is a highly processed sweetener made from corn. Essentially, it is made by processing corn syrup to convert some of the glucose it contains into fructose in order to obtain a certain level of sweetness.

The recipe for making HFCS has sometimes included the addition of chlor-alkali chemicals hydrogen chloride and sodium hydroxide. Chlor-alkali plants manufacture these chemicals using a variety of different technologies, including one called mercury cell production. Unfortunately, the use of mercury cell chlor-alkali chemicals in food manufacturing can lead to mercury residue in the final food product.  While the food industry claims that it no longer uses mercury cell technology, we are not aware of any independent verification of that fact.

Manufactures also may have an incentive to use mercury cell chlor-alkali chemicals because they are known to enhance product shelf life. Mercury residue has previously been found in high fructose corn syrup samples collected and analyzed in 2005 and products made with high fructose corn syrup in 2009 and 2010. Some companies have switched to using chlor-alkali chemicals made using the membrane process, due in large part to consumer sentiment against mercury residue in food.

Q: What is the comparison between autism rates in the U.S. and Italy?

The study compares environmental and dietary factors in Italy, where autism prevalence is low (1 in 1000, or 0.1%) whereas in the U.S. the rate is now estimated to be 1 in 88, more than 10 times higher. This study compares autism prevalence in the two countries using a unique macroepigenetic approach to identify the factors already associated in the scientific literature with increased risk of autism.


Exposure to mercury from several sources such as air pollution, fish consumption and dental amalgam is similar in both countries. Where the two countries differ significantly is in the consumption of HFCS—almost non-existent in Italy—while the average American now consumes 35.7 lbs per year.

Q: Where can I go for more information?

A: Visit the Food Ingredient and Health Research Institute ( for more information about food ingredient safety, education and research, including the previously published papers by Dufault and co-authors.

You can also download IATP’s report Not So Sweet on HFCS in food products.


  1. Case Western Reserve University, “Electrochemistry encyclopedia: brine electrolysis,” (2007). Accessed April 27, 2012 from
  2. Renee Dufault et al. “Mercury from chlor-alkali plants: measured concentrations in food product sugar” Environmental Health 8:2(2009) Retrieved from
  3. Martha Herbert and Karen Weintraub, The Autism Revolution: Whole-Body Strategies for Making Life All it can be (Ballantine Books, 2012).
  4. Karen Rideout et al. “Comment on the paper by Dufault et al.: Mercury in foods containing high-fructose corn syrup in Canada” Environmental Health (2010-07-21). Retrieved from
  5. United States Department of Agriculture, Economic Research Service. The EU sugar policy regime and implications of reform, “Sugar Substitutes,” page 5. Retrieved from