Pollutants and the Healthy Child

Compared to adults, children are at a higher risk for exposure to environmental toxicants and more sensitive to the potentially severe health consequences.¹ Persistent organic pollutants (POPs) such as polychlorinated biphenyls (PCBs) and dioxin are endocrine-disrupting chemicals (EDCs) that persist in the environment and bioaccumulate in the food chain; bisphenol A (BPA) and phthalates are toxic chemicals commonly used in plastics and personal care products; pesticides and toxic heavy metals may be present in food and water sources. And evidence suggests that prenatal or postnatal exposures to such ubiquitous toxicants may negatively impact a child’s growth and development,^1-3 alter their immune system function,⁴ or increase their risk of chronic disease.^5,6

The overall toxic burden throughout one's life may impact disease burden and quality of life. Given the reality of pervasive environmental contaminants, how do clinicians best address exposure concerns for pediatric patients and develop a treatment plan to build healthy adults? 

Neighborhood Health

A healthy environment contributes to a healthy child and assessing the “health” of a patient’s neighborhood may indicate their potential exposure level to toxic chemicals. A 2021 cohort study of school-aged children ages 6-8 (n=221; 77% Hispanic participants) living in Fresno, California, a city with reportedly elevated pollution levels, investigated the association between exposure to multiple ambient air pollutants and both immunological and cardiovascular outcomes.⁴ Results indicated that daily exposure to fine particulate matter (PM_2.5), carbon monoxide, and ozone was linked to altered methylation of immunoregulatory genes and changes in blood pressure measurements, suggesting negative impacts to a child’s immune and cardiovascular systems.⁴ A 2020 review of studies regarding US-based communities living close to industrial complexes that use or emit hazardous chemicals (e.g., natural gas drilling, large dairy operations, and smelting facilities) suggested links between proximity and negative pediatric health outcomes such as:⁷

• Low birth weight
• Risk of pre-term birth
• Prevalence of neural tube defects
• Higher blood lead levels

Some of the noted detrimental health impacts were reportedly amplified for children living in neighborhoods of lower socioeconomic status.⁷ Further, studies continue to illustrate environmental exposure disparities in the US, with low-income populations and communities of color disproportionately exposed to and affected by pollutants.^8,9

A Focus on Heavy Metal, EDC, and Pesticide Exposures

Depending on concentration and length of exposure, the toxicity of prevalent heavy metals such as mercury, lead, chromium, cadmium, and barium may inflict a range of harmful consequences on children’s health, including neurocognitive, behavioral, and congenital disorders as well as respiratory problems, cancer, and cardiometabolic diseases.¹⁰ As an example, a 2017 JAMA study linked higher childhood lead exposure with lower IQ scores and downward social mobility in adulthood.¹¹ In addition, a recent analysis from a large cohort study (n=1,751 women) indicated that prenatal mercury exposure in mothers with low prenatal folate levels adversely affected infant neurodevelopment.¹² The exposure was also associated with rapid catch-up growth in the first three years of life,¹² which has been shown to have both obvious short-term benefits and potential long-term metabolic risks such as childhood obesity.¹³ 

Endocrine dysfunction related to EDC exposures may lead to systemic imbalances that increase the risk of adverse health effects, and developing fetuses are especially vulnerable. Both animal models and human cohort studies have suggested that such exposures have the potential to alter fetal growth and metabolism, potentially promoting metabolic disorders in adulthood such as obesity, type 2 diabetes, and metabolic syndrome.¹⁴ In addition, a 2020 systematic review and meta-analysis examined the association between postnatal exposure to EDCs and obesity.¹⁵ Of the included 73 mostly cross-sectional studies, 16 were conducted among children or adolescent participants. Pediatric results from qualitative and meta-analysis indicated:¹⁵

• BPA and phthalate exposures were associated with general and abdominal obesity in children.
• A significant association was noted between exposure to the organic compound 2,5-dichlorophenol and obesity in children.

Specific to chronic, low-level pesticide exposure during childhood, epidemiological, animal, and clinical studies suggest an association with alterations in growth, impaired neurobehavioral development, cancer, and increased vulnerability to infection.^16,17 Most recently, a 2021 study reviewed the epidemiological evidence regarding pyrethroid pesticides (chemicals also used in commercial and household insecticides) and health impacts among agricultural workers and their children.¹⁸ Limited US studies were included in the review; however, investigators reported that in 66.6% of the reviewed studies (8 of 12), workers or their children exposed to pyrethroid pesticides had a higher risk of impairment to neurocognitive, neuromotor, or neurobehavioral performance, mainly associated with attention, processing speed, and motor coordination.¹⁸

Clinical Applications

The prenatal period and the first years of life are a critical period for prosperous pediatric development and wellness throughout life. Acute or long-term exposures to environmental contaminants may interfere with a child’s health trajectory, depending on chemical concentrations and duration. To understand a patient’s complete story, highlighting potential sources of low-level or excess toxicant exposure is a crucial component of a clinical assessment. From prenatal to postnatal, this assessment may include various considerations including:

• Eating and lifestyle habits during pregnancy 
• Neighborhood location and health
• Ambient air pollution exposure
• Indoor toxicant exposures such as in cleaning products, molds, carpets, and toys 
• Water quality and intake of non-organic foods more likely to contain pesticide residues

While many toxic chemicals are ubiquitous and difficult to avoid completely, reducing contact with potential sources is an important goal. Identifying those contaminants specific to a patient’s daily life is a first step; improving biotransformation and elimination processes by supporting liver and gut health can be the next. This may include increasing intake of phytonutrient-dense foods, quality proteins, and healthy fats as well as sufficient water intake and pediatric-designed probiotics. It may also include avoiding those foods that are difficult for a patient to digest and excrete such as fried foods or ultra-processed meals. Functional medicine’s patient-centered approach helps parents and practitioners co-develop a personalized health plan for pediatric patients.