According to the U.S. Department of Health and Human Services, there are more than 80,000 chemicals in use in the United States. Each year, an estimated 2,000 new ones are introduced for use in everyday items such as food, personal care products, prescription drugs, household cleaners, and lawn care products. You may be wondering, can some of these chemicals cause dysfunction of our brain function?
To find out, we will concentrate on two important functions: cognition and intelligence. They are mostly developed in the cerebral cortex of the brain but there is no pin pointing the actual area responsible for this function. Cognitive function includes reasoning, memory, attention, language, and one’s capabilities are usually assessed using various IQ tests.
Your cognitive and intelligence is influenced by 2 major factors - mood and state of health. Both of these factors are constantly in correlation with the environment and personal habits. The following toxins are some of the most common chemical exposures that can harm you’re your brain and your cognitive abilities.
Mercury is currently ranked third by the US Agency for Toxic Substances Registry for the most toxic substances on the planet, surpassed only by arsenic and lead.
It can be found in the following forms:
Elemental mercury – found in thermometers, incandescent light bulbs
Inorganic mercury - found in soil and water due to human activities
Organic as methyl mercury - found in seafood like tuna and shrimp
A study published in 2001 (Carries Research magazine), found amalgam fillings may be a continuous source of organic mercury, which is more toxic than inorganic mercury, and almost completely absorbed by the human intestine. The average half-life of mercury in the human body is around 60-70 days, but it’s mostly toxic due to bio accumulation in the brain, where its half time can reach up to 20 years.
Mercury primarily lowers the antioxidant capacity of the cells making them more prone to oxidative stress and damage. Furthermore, it can also alter the blood-brain barrier making it more permeable for other toxins and chemicals. A study conducted in New Zealand with 465 patients diagnosed as having chronic mercury toxicity, 32.3% had severe fatigue, 88.8% had memory loss, and 27.5% had depression.
Large exposure of mercury over time might lead to mental retardation, dysarthria (dysfunctional speech), blindness, depression and even paranoia. Mercury can pass through the placenta and affect the development of the fetus leading to autism-like syndromes for the newborn baby.
There is an actual condition called “The Mad Hatter Syndrome “, an occupational disease for hatmakers at the 17th century France. It was caused by chronic exposure to inorganic mercury used to treat animal furs for the manufacture of hats. Some of the symptoms included dementia, red cheeks, and fingers, loss of hearing and emotional disturbances and shyness.
Does it sound familiar? Maybe next time you watch “Alice in Wonderland” you’ll see the Mad Hatter in a whole new light.
Lead can be found in soil and dust particles in the vicinity of gold mines and lead smelters, yet the main exposure source is found in contaminated water supplies and lead paints. According to United States Environmental Protection Agency, lead can enter drinking water when service pipes that contain lead corrode, especially pipes in houses that were build 1986. Lead is toxic to everybody; however children and pregnant women are especially at risk of lead poisoning. In 2016 the CNN and The Guardian repoted that high and dangerous levels of lead were found in 5,363 water systems in the U.S., exposing over 18 million Americans to lead.
Lead acts as a neurotoxin at the central nervous level. It competitively displaces calcium ions in neuronal proteins causing brain development abnormalities in children.
High blood levels of lead during childhood were found to be responsible for poor reading, writing and spelling grades on standardized tests compared to other children that had no exposure.
Additionally, the US national toxicological report concluded that children with 5μg/dL (micrograms per decilitre) of lead in the blood are more prone to developing antisocial behavior problems and a shorter attention span.
Adults that are exposed might experience cardiovascular effects, increased blood pressure, decreased kidney function, reproductive problems (in both men and women), as well as psychiatric symptoms; such as depression, irritability and difficulty managing feelings of anger and even personality changes. All these effects can, in time, lead to cognitive impairment.
Fluoride is recognized as the world’s 13th most abundant chemical. It is found in water, soil, air and rocks. During the 1940’s, studies have shown that low concentrations of fluoride can prevent dental cavities. Therefore, the government of the United States decided to fluoridate water supplies as a method to prevent dental damage.
A 2014 review suggests that water fluoridation can cause major health problems due to the hazardous consumption of fluoride. It has been shown to affect nervous system development in children. Fluoride can pass through the placenta and mothers who consume high amounts of fluoridated water can give birth to babies with impaired cognitive skills.
This is a synthetic insecticide created by Dow Chemical Company during the 1960’s. It was widely used in homes and farms in controlling pests. You can still find it applied on almonds, oranges, corn crops and apples.
Main exposure is due to ingestion of treated fruits and plants. Ingesting small amounts of this insecticide can lead to symptoms such as dizziness, difficulty focusing, blurred vision and even loss of consciousness.