Attention has focused on a recent study in the Archives of Pediatrics & Adolescent Medicine journal, associating mothers’ exposure to mercury while pregnant with a greater risk of ADHD-related behavior in their offspring.
The research coincides with another recent study that correlated increase in prevalence in the US of attention deficit hyperactivity disorder (ADHD) --along with other developmental disorders, including autism –with the introduction of high fructose corn syrup (HFCS) to the American food supply. The link is that until quite recently it was common for HFCS to be manufactured using mercury contaminated caustic soda.
Together the findings are leading to closure examination of the myriad toxins fetuses are exposed to such as lead, nicotine, pesticides, and mercury, and which science shows may contribute to the development of brain and behavior disorders.
In the case of mercury, exposure from food occurs through the consumption of fish, high fructose corn syrup and food colors according to a relatively recent article published in the Behavioral and Brain Functions journal. The U.S. Department of Agriculture keeps a record of U.S. fish and high fructose corn syrup (HFCS) consumption on a website. Americans consume on average, 9.5 pounds per year of fish and shellfish and 28.7 pounds per year HFCS.
In the most recent study, researchers collected hair samples for mercury analysis and fish consumption data from mothers during pregnancy. They determined that fish consumption during pregnancy can protect somewhat against ADHD – it’s known, for example, that fish and shellfish provide the human body with the essential omega-3 fatty acids required for maintaining neuronal plasticity and learning capacity. But that’s not the whole story. As the mother’s mercury exposure increased in the study, so too did the child’s risk of developing ADHD. The children underwent neuropsychological testing at 8 years old to determine whether or not they exhibited inattention, impulsivity or hyperactivity.
To avoid mercury exposure from fish consumption, the U.S. Food and Drug Administration advises women and children to eat smaller fish with lower mercury levels and avoid eating the larger species of fish that contain higher mercury levels. Low-mercury seafood are the species found at the bottom of the food chain such as sardines, clam, tilapia, haddock, flounder, squid, salmon, oysters, crab, scallops, sole, trout, shrimp, catfish, crawfish, and anchovies.
HFCS on the other hand is of no nutritional value to the human body and is considered a sugar substitute. HFCS is the most common “added sugar” to food products. High fructose corn syrup is the most ubiquitous ingredient found in processed foods today and this explains why on average each American consumes 28.7 pounds per year of this ingredient. In a recent report, the Centers for Disease Control (CDC) recommended that children reduce their dietary intake of all added sugars including HFCS to prevent the development of diseases associated with them.
The chlor-alkali chemicals once widely used and perhaps still used to manufacture HFCS can leave trace amounts of mercury in the product according to researchers who published their research findings in an article in 2009. In Europe, HFCS is not widely consumed and blood mercury levels are much lower in European populations compared to Americans. Consumption of HFCS creates a number of pathways for the development of autism and ADHD. According to a Mercury Toxicity Model published in 2009, consumption of HFCS can lead to the bioaccumulation of mercury in sensitive populations. This bioaccumulation may occur when consumption of HFCS leads to mineral imbalances that interfere with the elimination of heavy metals such as mercury. When heavy metals accumulate in the body of a child, neurodevelopment is delayed or in some cases behavioral disorders arise. If the child is also diet deficient in magnesium or calcium it increases the risk of heavy metal bioaccumulation even further.
Fructose consumption also can lead to the development of autism, according to another study, by interfering with the expression of key gene, called the PON1gene. This gene is responsible for production of an enzyme that breaks down organophosphate pesticides. If not broken down and excreted, these pesticides wreak havoc on the brain and nervous system. While Americans on average eat well over 100 pounds per year of wheat and corn that is often contaminated with organophosphate pesticide residues, he or she also consumes 28.7 pounds per year of HFCS – the same substance, as it turns out, used by scientists to suppress PON1 gene expression and create disease conditions in animal experiments.
Food and diet are key factors in potentially mitigating the interactions between genes and toxins in the environment and protect against neurodevelopmental disorders like ADHD and autism. In consuming the Standard American Diet, the sad truth is that pregnant women cannot realize these protections. Instead , the fast and processed foods so common to this diet contain lead, mercury, pesticides these and other toxic substances that may impact fetal brain development.
So for families planning to get pregnant and hoping for the best outcome, refrain from the consumption of high fructose corn syrup and alcohol as well as other chemicals found in processed foods. Eat fish low in mercury and plenty of whole, organic foods.