As discussed above, there are many chronic health disorders affecting children. Of concern, there are escalating rates of endocrinologic issues, asthma/ allergies/eczema, behavioral and mental health issues in children, and a grave issue is in regard to neurocognitive dysfunction. Using US data for comparison, the prevalence of Autism Spectrum Disorder (ASD) can be seen as a canary in the coal mine or the flagship of the deterioration of our children’s health and will be presented in comparison to African children. As we begin to dissect the causes of these issues in children, a brief review on the physiologic differences between children and adults will be presented as well as an explanation as to why this is so important in understanding the role of pesticide toxicity on children’s health.
Understanding pesticide exposure in children
In relation to their body weight, children have a larger skin surface area than adults, breathe in more air and drink and eat more, hence they experience a much higher exposure rate than adults.
Common routes of exposure for many children occur via the dermal and inhalational routes. Children are closer to the ground, often play barefoot in pesticide-sprayed areas and explore much of their world via hand-to-mouth behaviors. Pesticides can cross the epithelium of the skin and mucous membranes that exchange gases (alveoli) or via the gastrointestinal mucosa.
The rate of absorption depends on the chemical properties, amount of the chemical, length of exposure and the physical state of the actual pesticide molecules. There are also other factors that may contribute to increased absorption, such as skin absorption is higher when there is vasodilatation (e.g. in summer or with heating), which would be more of a problem on the African continent.
Respiratory absorption is many times higher when respiration is more rapid, e.g. when playing or running. Children have a much higher respiratory rate than adults and thus have a greater exposure via inhalation.20
Another important consideration is how children detoxify xenobiologics, particularly in comparison to adults. The first line of defense in processing foreign chemicals resides in the intestinal microbiota; the collection of organisms that are found in the large intestine, vital to the health of the child and one of the most important areas of study and treatment in modern medicine.
This vast community of organisms (consisting of bacteria, archaea, fungi and viruses) have been shown to be impacted by pesticides that act as antibiotics.21 For example, glyphosate, the main ingredient in Roundup® was patented by Monsanto (now Bayer) as an antibiotic in 201022. Mechanisms on how glyphosate affects the microbiota have been demonstrated as well as
potentially elucidated the link between glyphosate and cancer.23 (In 2015, the WHO via its specialized cancer agency, the International Agency for Research on Cancer (IARC), classified glyphosate as a class IIa carcinogen.24,25) Glyphosate has been found in both breast milk26 and infant formula27, so either method of nutrition will expose infants to glyphosate from the very first stages of life.
From a clinical perspective, again, there is tremendous importance in the role of the microbiota in terms of children’s health. Children acquire their microbial communities from their mothers during vaginal births as well as breastfeeding.
(Of note, progress is being made in Africa to support mothers to breast feed their infants for the first 6 months which is a source of nutrients and immune development as well as infant immune support via the breast milk microbiota.)28