Over the past several decades, awareness of the dangers posed by certain chemicals and consumer products has grown exponentially. This awareness has fundamentally changed consumer habits, manufacturing practices, and public policy as people have sought to protect themselves from harm, whether in the form of drastically falling smoking rates, lead paint bans, or tight regulation on asbestos. But despite these shifts in knowledge and practice, we remain surrounded by a plethora of toxins that may produce significant damage to human health. For example, a flourishing body of evidence suggests that common chemicals in consumer products like shampoo, canned goods, or water bottles have the potential to disrupt critical hormonal processes while also carrying teratogenic risks and potential carcinogenicity. Unfortunately, widespread recognition of these risks has been slow, leading to high-volume exposure and subsequent negative health impacts. Even when following the directives of regulators and environmental authorities, members of the public continue to be at risk, and few health-enhancing tactics are offered. This is where renowned environmental medicine researcher Walter Crinnion comes in.
By scrupulously identifying toxins in our home environments and elsewhere, Crinnion aims to raise awareness of the subclinical-scale damage inflicted by pollutants present in our everyday lives and empower the public to prevent it. Recently, he joined us to discuss the burgeoning field of environmental medicine and the growing need to protect ourselves from the cumulative effects of long-term exposure to certain ubiquitous chemicals. In part two of our interview, Crinnion expands his discussion on the most pernicious environmental toxins and shares practical strategies for mitigating their impact, including fortifying our bodies’ ability to cope with inevitable stressors.
Recognizing the Multiple Dangers of Automobile Exhaust
Vehicle exhaust is a mixture of carcinogenic, toxic, teratogenic, immunosuppressive, and system-disruptive chemicals, yet most people are exposed to it daily in significant concentrations, especially if they live in an urban area. “The sheer number of public health problems—including mortality—associated with vehicular exhaust is overwhelming,” Crinnion says. While the research into the negative impacts of vehicle exhaust thus far has focused on its carcinogenicity, this exhaust can negatively affect nearly all of the body’s systems, including the highly sensitive structures of the brain involved in cognition and memory consolidation. “Vehicle exhaust is associated with reduced cognition and Alzheimer’s disease,” Crinnion explains. “In one study in the Mexico City area, 2-5-year-olds have been found with Alzheimer’s pathology in their brain, which was associated with the level of particulate matter that they’re exposed to.”
One of the reasons vehicle exhaust is so dangerous is that it causes immediately harmful physiological changes, particularly in people who are already in poor health. After exposure to diesel exhaust, for example, immune cells secrete proinflammatory cytokines, prompting inflammation in surrounding tissues. At the same time, these immune cells become anergic, meaning that they are less capable of responding to new threats—or simply preserving their life—until they recover from their fatigued state. Elsewhere, the mucosal surfaces of the respiratory tract are rich in T-cells, which means that they are especially prone to being aggravated by contact with the airborne contaminants in vehicle exhaust. As a result, Crinnion believes that chronic exposure to vehicle exhaust contributes towards respiratory disease and allergies, and a substantial body of research agrees. Indeed, pulmonary tissues are the site of the largest amount of inflammation. Vehicle exhaust is also known to be a significant contributor to cardiovascular disease and heart attacks. As Crinnion notes, “Air pollution is more strongly linked to heart attacks than cholesterol is.”
Some of the risks associated with vehicle exhaust, such as cardiovascular disease, require significant duration of exposure and are therefore primary concerns for adults. Others, such as infertility and in-vitro fertilization failure, typically only become apparent in adulthood. However, exhaust also poses an immediate and emergent threat to the young, starting at conception, and researchers have consistently found that chronic prenatal exposure to contaminants is exceptionally hazardous. “The closer a mother lives to a busy roadway with truck traffic with diesel exhaust, the higher her risk of having a child with autism. There have been many studies documenting this,” Crinnion says. One systematic review, for example, found that 8 out of 13 studies documented a correlation between exposure to particulate matter in vehicle exhaust and subsequent children with autism spectrum disorder (ASD) or attention deficit hyperactivity disorder (ADHD). The review did not find any correlation between the severity of the subsequent ASD or ADHD and the level of exposure prenatally or postnatally, however, a point which other researchers have also raised. However, researchers remain skeptical that the negative results regarding the link between level of exhaust and autism severity are genuine. Despite the remaining questions regarding the link between the level of exhaust exposure and severity of the disorders after birth, the current research is unambiguous: especially for children, preventing exposure to automobile exhaust promotes healthy development and has the potential to ward off medical problems later in life.
When it comes to preventing exposure to vehicle exhaust, government regulators have long positioned themselves as the first line of defense. Air pollutants like vehicle exhaust are regulated by organizations like the Environmental Protection Agency (EPA), which can set caps on industrial emissions and dictate the maximum safe concentrations of chemicals in the air. But EPA regulations are not a panacea, and Crinnion is skeptical of the government’s ability to protect and inform the public of environmental risks. “If the public doesn’t know about this stuff, how can they avoid it?”
Crinnion points out that some EPA regulations that appear to support public health ultimately do not prevent harm in any meaningful way. New requirements for new vehicle-based exhaust filters, for example, do not translate into lower physiological damage for the people who are exposed. In other cases, regulations are only passed by the EPA years after the pollutants have been linked to poor health outcomes, and enforcement of EPA regulations is inconsistent and often delayed. Other regulations have been rolled back entirely. Ultimately, Crinnion says, the public can’t rely on the government to protect them from environmental threats, and they must take matters into their own hands.
Crinnion’s Holy Trinity Of Environmental Health
The project of protecting public health on a population level can be slow-moving, but there are important steps individuals can take to minimize damage from environmental toxins. Unfortunately, while avoiding the use of consumer goods containing harmful chemicals is an obvious choice, many feel powerless to avoid omnipresent airborne toxins like vehicle exhaust. To address this, Crinnion is a proponent of what he calls the “holy trinity” of harm mitigation methods:
- Habitually removing ambient contaminants present in dust from HVAC systems
- Equipping furnaces and AC units with high-quality air filters to prevent additional contaminants from being brought in from the outside air
- Installing a home air purifier with similarly potent filters
Using these three methods in conjunction can drastically cut down on the quantity of environmental contaminants present in the home. Significantly, even the most deleterious components of vehicle exhaust will be caught by the right air filters; one 2015 study found that using a high-grade filter reduced indoor exhaust particulates by as much as 40%.
Implementing Crinnion’s trinity intelligently may require a bit of professional help. Most people aren’t able to perform a deep clean of their home’s HVAC system on their own, meaning that unless they have installed many sets of filters, pollutants will simply return to living areas when the ventilation system moves air around the ductwork. Likewise, many people do not have access to the parts of their ventilation system that can accommodate the filters. To address these issues, Crinnion suggests hiring an HVAC cleaning company to vacuum out dust particles laden with contaminants before adding new filters and purchasing an air purifier.
With these recommendations, Crinnion is ahead of many general practitioners, but consistent with the best practices currently proposed by allergists and pulmonary specialists. But far from merely reiterating the suggestions of other specialists, Crinnion also has a cutting-edge suggestion for mitigating the damage caused by inhaling vehicle exhaust and contact with other pollutants: supplementing the body’s defenses.
The Promise of Glutathione Supplementation
One of the primary mechanisms by which environmental toxins cause damage is oxidative stress. Oxidative stress occurs when cells are exposed to molecules called reactive oxygen species (ROS), which are generated by a wide range of stimuli, including the vehicle exhaust, bisphenol-type plasticizers, and phthalate class chemicals Crinnion has discussed. ROS interfere with cellular function by inactivating enzymes and other components that cells need to survive. If left unaddressed, oxidative stress damage can accumulate and eventually cause cells to die. To prevent this damage, cells naturally synthesize a molecule called glutathione whose purpose is specifically to handle ROS safely to prevent oxidative stress damage; when ROS threaten cellular machinery the ROS will react with glutathione rather than the healthy cell, allowing the cell to dispose of the inactivated ROS by recycling the glutathione later on.
However, the glutathione produced by the body may not be enough to prevent oxidative stress damage. “Glutathione is one of the most important molecules for people’s overall health, but 25% of the public has a mutation that impairs glutathione synthesis,” Crinnion explains. This mutation means that at least 25% of the public is at greater risk of experiencing negative health effects from environmental contaminant exposure, as they will naturally have less glutathione to compensate for oxidative damage. But the scientific literature provides an additional caveat: even those with normal or augmented glutathione synthesis are endangered by ROS.
Glutathione has been shown to reduce the negative impacts of inhaled diesel exhaust in animal model studies. However, these studies also showed that free glutathione was heavily depleted from the cells after exposure to diesel exhaust. This is to be expected, as glutathione must hold ROS before it can be recycled by the cell. But even the animals which had been genetically engineered to have five times as much glutathione than normal animals were depleted of roughly 95% of their glutathione molecules after 6 hours of exhaust exposure at the intensity of ambient air in a suburban area, demonstrating how drastically vehicle exhaust can affect the body. Depletion in excess of 90% is linked to irreversible vascular injury—a threat to which the majority of the population is exposed regardless of their genetics.
Crinnion believes that it may be possible to mitigate oxidative stress damage caused by pollutants like vehicle exhaust by taking a glutathione supplement, which might boost the body’s levels of glutathione to the point where trace exposure to toxins doesn’t overwhelm cells’ ability to cope. As such, healthy cellular function would be preserved. To illustrate why he believes that supplemental glutathione could effectively prevent environmentally-induced damage, Crinnion recalls a clinical study in which people with HIV with very low glutathione levels were provided a glutathione supplement. “When supplemental glutathione was given, the cytokine profile was very close to a healthy cytokine profile,” Crinnion says. Given that cytokines are molecules which cells use as signals to regulate their activity or the activities of other cells, the fact that glutathione could restore a healthy cytokine profile means that it was also helpful to restore normal cellular functions and behavior.
For the members of the public who want to protect themselves immediately, sophisticated glutathione supplements are already on the market. People who take these glutathione supplements could potentially avoid the negative impacts of vehicle exhaust, provided that they took it consistently enough to offset the background level of air pollution in most areas. While there isn’t yet any data in humans regarding how effective glutathione supplements might be at protecting people from the negative impact of vehicle exhaust, Crinnion is optimistic. “Repletion of glutathione can help to reverse depletion, but so can avoidance of these common pollutants that can lead to it, and I think that a combination of both is the best way to go.”
Taking the Next Steps
As Crinnion’s research expands and the field of environmental medicine continues to grow, we may see policy changes aimed at protecting public health by eliminating toxins at the source. But given the lack of regulatory ambition with regard to air pollution and chemicals used in consumer products, practicing environmental health principles on an individual level will likely be increasingly necessary. As such, public health may soon become a process of teaching people to avoid the hazards present in their environment. With time and enough public involvement, however, promoting environmental medicine perspectives may cause manufacturers of consumer products and vehicles to voluntarily exclude currently identified toxins from their products. In order for that to happen, the public must recognize that maintaining their health stands in opposition to those who profit from the status quo and subsequently vote for safer products with their wallets, however. Until then, Crinnion’s holy trinity combined with glutathione supplementation offers a multi-pronged approach to preserving health and wellbeing.
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