Updated on May 4, 2023
Over the past several decades, awareness of the dangers posed by certain chemicals and the consumer products that contain them has grown exponentially. This awareness has fundamentally changed consumer habits, manufacturing practices, and public policy as individuals are increasingly seeking 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 environmental toxins that can produce significant damage to human health. For example, a flourishing body of evidence now suggests that common chemicals in household consumer products, like shampoo, canned goods, and 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 governmental regulators and environmental authorities, members of the public continue to be at risk, and few health-enhancing tactics are offered. This is where the renowned environmental medicine researcher, Dr. Walter Crinnion, remains an invaluable source of information.
During his lifetime, by scrupulously identifying toxins in our home environments and elsewhere, Dr. Crinnion aimed to raise awareness of the subclinical-scale damage that can be inflicted by pollutants present in our everyday lives and to 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 an interview that took place before his untimely passing at age 66, Dr. Crinnion expanded his discussion on the most pernicious environmental toxins and shared practical strategies for mitigating their impact, including fortifying our bodies’ ability to cope with inevitable stressors.
Recognizing the Multiple Dangers of Automobile Exhaust
Much of environmental medicine is focused on investigating the dangers of materials found in consumer goods. Indeed, in part one of this interview, Dr. Crinnion explored two such significant culprits—bisphenols and phthalates. However, when asked to identify the most dangerous compound with which the public regularly comes into contact, Dr. Crinnion didn’t name a chemical integrated into a particular consumer product. Instead, without a hint of hesitation, he said, “Vehicular exhaust. Urban air pollution. Without a doubt.”
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,” Dr. Crinnion said.
Although the research into the negative impacts of vehicle exhaust thus far has focused on its carcinogenicity, this exhaust can negatively affect nearly every body system, 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 explained. “In one study in the Mexico City area, two-to-five-year-olds were found with Alzheimer’s pathology in their brains, which was associated with the level of particulate matter they are exposed to.”
One of the main reasons vehicle exhaust is so dangerous is that it causes immediately harmful physiological changes, particularly in individuals 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 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 they are especially prone to being aggravated by contact with the airborne contaminants in vehicle exhaust. As a result, Dr. Crinnion believed that chronic exposure to vehicle exhaust contributes toward 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 Dr. Crinnion noted, “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, vehicle exhaust also poses an immediate and emergent threat to the young, starting at conception, and researchers have consistently found that chronic prenatal exposure to these 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,” Dr. Crinnion said.
One systematic review, for example, found that 8 out of 13 studies documented a correlation between maternal exposure to particulate matter in vehicle exhaust and subsequently born children with autism spectrum disorder (ASD) or 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 that other researchers have also raised.
Nevertheless, researchers remain skeptical that the negative results regarding the link between level of exhaust exposure 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; i.e., 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 federal agencies like the U.S. 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 Dr. Crinnion was always skeptical of the federal 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?”
Dr. Crinnion pointed out that some EPA regulations that appear to support public health ultimately do not prevent harm in any meaningful way. For example, nNew requirements for new vehicle-based exhaust filters do not translate into lower physiological damage for those 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, Dr. Crinnion said, the public can’t rely on the federal government to protect them from environmental threats, so they must take matters into their own hands.
Dr. Crinnion’s Holy Trinity Of Environmental Health
Although the project of protecting public health on a population level can be slow moving, 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, Dr. Crinnion was an ardent proponent of what he called the “holy trinity” of harm mitigation methods:
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; a 2015 study found that using a high-grade filter reduced indoor exhaust particulates by as much as 40 percent.
Implementing Dr. Crinnion’s “holy trinity” intelligently might require a bit of professional help. Most individuals aren’t able to perform a deep clean of their home’s HVAC system on their own, meaning that unless they have installed multiple 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, Dr. Crinnion suggested 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, Dr. Crinnion was significantly ahead of many general practitioners, and consistent with the best practices currently proposed by allergists and pulmonary specialists. Dr. Crinnion also had 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 the body’s cells are exposed to molecules called reactive oxygen species (ROS), which are generated by a wide range of stimuli, including vehicle exhaust, bisphenol-type plasticizers, and phthalate class chemicals that Dr. Crinnion discussed earlier in this interview. ROS interfere with cellular function by inactivating the enzymes and other components that cells need to survive. If left unaddressed, then oxidative stress damage can accumulate and eventually cause cells to die.
To prevent this damage, cells naturally synthesize a tripeptide derived from cysteine, glutamate, and glycine – glutathione, whose primary 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 might not be enough to prevent oxidative stress damage. Dr. Crinnion explained that although “Glutathione is one of the most important molecules for people’s overall health, 25 percent of the public has a mutation that impairs glutathione synthesis.” This mutation means that at least 25 percent of the public is at greater risk of experiencing negative health effects from environmental contaminant exposure, because they will naturally have less glutathione to compensate for oxidative damage. But the scientific literature includes an additional caveat: even those individuals who have normal or augmented glutathione synthesis remain 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, because glutathione must hold ROS before it can be recycled by the cell. But even the animals that had been genetically engineered to have five times as much glutathione than normal animals were depleted of roughly 95 percent of their glutathione after six 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 percent is linked to irreversible vascular injury—a threat to which the majority of the population is exposed regardless of their genetics.
Dr. Crinnion firmly believed that it was possible to mitigate oxidative stress damage caused by pollutants like vehicle exhaust by taking a glutathione supplement, which would boost the body’s level of glutathione to the point where trace exposure to toxins wouldn’t overwhelm cells’ ability to cope. As such, healthy cellular function would be preserved.
To illustrate why he believed that supplemental glutathione could effectively prevent environmentally-induced damage, Dr. Crinnion recalled 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,” Dr. Crinnion stated. Given that cytokines are molecules that 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 glutathione was also helpful to restore normal cellular functions and behavior.*
For individuals who want to protect themselves immediately, sophisticated glutathione supplements are currently on the market. Individuals who take a glutathione supplement could potentially avoid the negative impacts of vehicle exhaust, provided they supplemented consistently enough to offset the background level of air pollution in most areas. Although there wasn’t yet human data regarding how effective a glutathione supplement might be at protecting from the negative impact of vehicle exhaust at the time of this interview (nor is there presently), Dr. Crinnion was 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 Dr. Crinnion’s pioneering research continues to expand by those who have followed him, and the field of environmental medicine continues to grow, it is hoped that policy changes aimed at protecting public health by eliminating toxins at the source will be implemented. But given the lack of regulatory ambition regarding air pollution and chemicals used in consumer products, practicing environmental health principles on an individual level will likely remain increasingly necessary.
As such, public health will continue to be a process of teaching people to avoid the hazards present in their environment. With time and enough public involvement, however, promoting environmental medicine perspectives might cause manufacturers of consumer products and vehicles to voluntarily exclude currently identified toxins from their products. 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, Dr. Walter Crinnion’s legacy, his holy trinity combined with glutathione supplementation can offer a multi-pronged approach to preserving health and wellbeing.*
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