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Environmental Medicine and Toxins: An Interview with Dr. Walter Crinnion, ND, Part 1

Updated on May 4, 2023

Article Summary

  • Stressors constantly pressure the body, causing nearly undetectable changes that can ultimately result in disease or divergent physiology.
  • Walter Crinnion, who passed away in 2019, was a naturopathic doctor and pioneering researcher in the field of environmental medicine who had a deep understanding of the ubiquitous and under-acknowledged health hazards present in the modern milieu.
  • This article contains some of Dr. Crinnion’s thoughts, which are still very timely today, on some of the most pressing environmental hazards of our time and how the principles of environmental science can enhance public health and well-being.

Over the past several decades, undeniable evidence has emerged that pollutants in everyday life create significant harm to individuals over their lifespans. Stressors, such as particulates in the air, industrial chemicals in the water supply, and preservatives in food, constantly pressure the body, causing nearly undetectable changes that can ultimately result in disease or divergent physiology. Today, although the public generally knows to avoid environmental toxins like lead, asbestos, and air pollution, few individuals are aware of the scientific field responsible for identifying and developing coping strategies for these hazards: environmental medicine.

Walter Crinnion was a naturopathic doctor and pioneering researcher within the field of environmental medicine who had a deep understanding of the ubiquitous and under-acknowledged health hazards present in the modern milieu. While completing his naturopathic medical degree at Bastyr University, in Seattle, Washington, Dr. Crinnion began to recognize that the roots of some illnesses lay in the environmental toxins that surround us every day, and that these roots must be addressed to help individuals live full and healthy lives. To investigate and educate other medical professionals about the impact of these environmental stressors, Dr. Crinnion introduced environmental medicine classes at Bastyr University, the University of Bridgeport College of Naturopathic Medicine in Connecticut, and the Southwest College of Naturopathic Medicine (SCNM, now Sonoran University of Health Sciences) in Tempe, Arizona. 

At SCNM, Crinnion subsequently founded the department of environmental medicine and sat as its first chairman until 2013. Dr. Crinnion also founded the Naturopathic Association of Environmental Medicine, sat on the editorial review boards of Alternative Medicine Review, The New England Journal of Medicine, and Pharmaceutical Biology, and authored several books.

In this two-part interview conducted several years before his passing, Dr. Crinnion shared his thoughts on some of the most pressing environmental hazards of our time and how the principles of environmental science can enhance public health and wellbeing. 

Understanding the Goals of Environmental Medicine

At its core, Dr. Crinnion describes environmental medicine as “taking things away that are keeping your body’s natural way of healing itself from doing so.” Discovering what those things are, however, can be difficult. As Dr. Crinnion noted in a seminal 2000 paper characterizing environmental medicine, “Chemical compounds ubiquitous in our food, air, and water are now found in every person.” The overwhelming number of chemicals to which we are now exposed and the pervasive nature of that exposure makes differentiating between the dangerous and the benign a painstaking process because chemicals don’t necessarily have to be present in large amounts to produce harm, and the harm they do create might not be immediate. 

Rather, environmental toxins, such as bisphenol A and vehicle exhaust, can be damaging in trace quantities when exposure is constant over long periods of time. As Crinnion said, “The bioaccumulation of these compounds in some individuals can lead to a variety of metabolic and systemic dysfunctions, and in some cases outright disease states.” It is this that serves as the central site of inquiry within environmental medicine, and Dr. Crinnion hoped that his work and the field, in general, would herald a more aware and healthier public. 

It is important to note that environmental medicine isn’t simply toxicology. Toxicology deals with acute illnesses caused by high levels of exposure to relatively rare toxins with little emphasis on developmental impacts, carcinogenicity, or the ambient sources of toxins. Environmental medicine, on the other hand, focuses specifically on the development of chronic illnesses, congenital defects, or abnormal physiological functions that individuals are likely to experience as a result of contaminants or toxins that are highly prevalent in the modern lifestyle and modern surroundings. Additionally, where toxicology studies a poison as it impacts individuals at the time of acute symptoms, environmental medicine studies a pollutant as it occurs in populations. This means that environmental medicine can trace the population-level pathologies or physiological deviancies associated with exposure to pollutants so as to make public health policy recommendations, as well as consumer protection recommendations. 

Significantly, the core hypothesis of environmental medicine is that a lack of acute illness does not rule out negative impacts of common chemicals. This means that environmental medicine is also distinct from traditional medicine as a whole. “Normal medicine is what I call heroic medicine,” Dr. Crinnion explained. “You have a symptom, and I’m going to give you a medicine to fix it, which rarely looks at the root cause. Environmental medicine is saying, ‘What do I need to take away from the body?’ and, ‘What is poisoning your body?’” In other words, environmental medicine is concerned with removing barriers to peak function rather than adding resources to achieve peak function. 

However, environmental medicine researchers don’t claim to provide affirmative prescriptions to solve health issues the majority of the time. Instead, Dr. Crinnion then and others now interpret their role as that of academics and translators, expressing ideas and findings from the scientific literature to physicians and health officials so they might better support the public interest. 

The Impact of Endocrine Disruptors

One of the primary projects of environmental medicine is to identify pernicious chemicals that can cause subclinical yet unambiguously negative impacts on the human body. Many of the most dangerous such chemicals are endocrine disruptors, or compounds whose chemical structure is similar enough to human hormones that they behave the same way as those hormones do in the body. Although some endocrine disruptors are ingested orally from contaminated food, the majority appear to be consumed via transdermal contact with everyday objects that contain the disruptive chemicals. 

Although endocrine disruptors are rarely toxic, they can carry a bevy of negative health effects when administered chronically because of the way they change cellular functions. This made endocrine disruptors a critical area of investigation for Dr. Crinnion, and they still are for other environmental medicine researchers. 

Although the impact of endocrine disruptors varies drastically depending on the hormone mimicked and the host, they are typically especially damaging to neonates, fetuses, and young children because hormones are essential for regulating anatomical and physiological development. In terms of systems affected, endocrine disruptors tend to be the hardest on tissues within the reproductive systems, especially for males. Indeed, chronic exposure to endocrine disruptors in males can lead to a collection of symptoms that Dr, Crinnion equated with “grumpy old men”: low testosterone during peak reproductive age, low sperm count, infertility, and, potentially, asthma. 

In females, exposure to endocrine disruptors can induce reproductive cancers, early ovulation, and defects of the mammary tissue. Regardless of sex, low-level exposure to endocrine disruptors increases the chance of birth defects, metabolic disorders like diabetes, cancers of reproductive tissues, neurological problems, and cancers of the mammary tissue in both sexes. Notably, this same constellation of symptoms is caused by a handful of different endocrine disruptors present in everyday objects, meaning that bioaccumulation is all but guaranteed. Because of their persistence, ubiquitousness, and negative health impacts, the public should be aware of common endocrine disruptors and how to protect themselves. 


Among the most prevalent endocrine disruptors, bisphenol A (BPA) is especially pernicious and is generally known to the public. BPA is an omnipresent environmental hazard as a result of the chemical’s use in the manufacturing of many common products, including plastic bottles, canned goods, and thermal paper. It most likely enters the body via oral consumption and skin contact. Significantly, BPA mimics estrogen and might trigger early puberty in girls and delayed puberty in boys. Later in life, BPA exposure might increase the risk of developing breast cancer in both men and women. 

For fetuses and neonates, BPA is even more hazardous. Most fetuses are exposed to BPA in the womb as a result of maternal contact with products containing BPA. This prenatal exposure increases the risk of developing reproductive defects. The level of severity of these defects has been linked to quantity and duration of exposure; prolonged exposure at high concentrations while in the womb can cause male fetuses to develop undifferentiated sex organs that do not occur at the same anatomical position appropriate for males. There is also some evidence that neonatal BPA exposure drastically increases the risk of developing behavioral pathologies like autism spectrum disorder and ADHD. 

Additionally, prenatal BPA exposure in animal models is linked to profound deviations of the dopaminergic system of the brain, lending further support to the link between BPA and developmental, behavioral, and psychiatric disorders. As Dr. Crinnion noted, “All of these epidemic-scale public health issues are associated with finding these chemicals in the public.”

Unfortunately, BPA is so ubiquitous that it contaminates places where it is least expected. Although some individuals consciously avoid plastics that contain BPA, Dr. Crinnion noted that canned soup can carry a large BPA load despite not containing any plastic, making it a silent hazard that injures even those trying to avoid environmental toxins. Other canned goods also often use BPA as a resin liner to insulate the food in the can from the metal of the can for the sake of preserving flavor and freshness. 

Additionally, while many products now claim to be BPA-free, most people don’t realize that BPA is not the only bisphenol compound that exhibits toxic effects; bisphenol S is functionally identical to bisphenol A in terms of its physiological impact, and other bisphenols like bisphenol F also can be found in consumer products and food packaging. The available evidence suggests that all of the bisphenols are equally hazardous regarding their endocrine disrupting activity.

Dr. Crinnion believed that regulatory bodies didn’t do enough to protect the public from products that contain the highest levels of BPA or other contaminants. He said, “People say, if this were a problem, the government wouldn’t let it be produced. But the public can purchase neurotoxic precursors to sarin gas.” Indeed, although BPA is banned in some countries and advertised as absent in certain products, bisphenol S remains unrestricted except for a few municipalities like New York City. 

Blanket bans of the bisphenols do not exist in the United States, and the U.S. FDA has repeatedly reaffirmed its overtly counterfactual stance that BPA is harmless, even as evidence to the contrary has mounted for years. Despite FDA claims regarding BPA’s safety, the European Union and other international bodies have banned BPA in a handful of applications. Given the difficulty of getting regulators to protect the public when the threat is well-characterized and relatively old, Dr. Crinnion was a forceful proponent of teaching the public to defend themselves—and the bisphenols are only one major threat out of many others.


Although the bisphenols were among Dr. Crinnion’s chief concerns, phthalates are similarly threatening and carry overlapping health effects. Phthalates are chemicals used to increase the flexibility of plastics, and, like the bisphenols, are endocrine disruptors that are especially dangerous to males. “The higher the phthalates, the lower the testosterone, in men, women, and children,” Crinnion explained. “Now we have the phenomenon of 30-year-old males needing testosterone shots. Did their testicles become dysfunctional all of a sudden? They’ve been working for thousands of years, and now all of a sudden they’re not.” 

In addition to their roles as endocrine disruptors, phthalates are believed to also function as metabolic disruptors, making them exponentially more damaging. More specifically, Dr. Crinnion hypothesized that phthalates can disrupt the cellular mitochondria that are responsible for generating chemical energy for cells to use. As a result of this disruption, Dr. Crinnion linked phthalates to adverse metabolic impacts like type II diabetes and obesity, as well as behavioral pathologies. “Moms who have the highest levels of phthalates present have a risk of having a child with ADHD that is threefold higher than those with normal levels,” he explained, referencing a 2018 population-level study

That study, which examined a cohort of 553 children, indicates that a mother who had high urinary concentrations of phthalates during her pregnancy was three times more likely than those with low concentrations to have a child with ADHD. As Dr. Crinnion bleakly stated, “All she has to do is wrap all of her food in Saran wrap, and her child can have ADHD.” Other researchers agree: phthalates are linked to the metabolic conditions, as well as developmental and behavioral disorders, that have spiraled into veritable public health crises over the last 20 years.

Unfortunately, exposure to the phthalates is nearly constant. Unlike with some environmental contaminants, phthalates readily permeate through the skin, and a plethora of products, including shampoo, nail polish, and laminated flooring, are common sources of phthalate exposure. In urban areas, individuals are also commonly exposed to phthalates in the air. In his interview, Dr. Crinnion pointed out that household dust is often rich in phthalates owing to its use in flame-retardant ductwork. Indeed, environmental exposure to phthalates is so pervasive that most individuals never experience a total absence of it in their blood. 

Dr. Crinnion claimed that most U.S. adults have at least 11 of the 13 most common phthalates circulating in detectable quantities in their bloodstreams at any given time, and the CDC agrees. While avoiding phthalates altogether might not be possible, individuals seeking to minimize their contact should avoid flexible plastic products, insulation, laminates, paints, and epoxies wherever possible. 

Perfluorocarbons and Other Threats

Although the scientific community generally recognizes the dangers of chemicals like BPA and phthalates, there are some other chemicals whose hazards are only beginning to be recognized. Perfluorocarbons, for example, have maintained a reputation for being both safe and biologically inert for decades. Found in an abundance of different products, ranging from cosmetics to surgical tools to drinking water, perfluorocarbons were long thought to be biologically inert, and little research was performed regarding their effects. 

Well ahead of his time, Dr. Crinnion referred to 2014 research suggesting that perfluorocarbons might have bioaccumulative effects, including the development of pancreatic cancers, liver cancer, and kidney cancer. Furthermore, although the U.S. EPA has regulated the amount of perfluorocarbons in municipal water supplies since 2009, recent research indicates that the presently established limits are most likely far too high. 

The endocrine disrupting capability of the perfluorocarbons is unclear. Forthcoming research will elaborate on the risks of exposure, but at present, Dr. Crinnion’s typical environmental medicine suggestions still apply: foresighted individuals should avoid products with perfluorocarbons whenever possible, although the public might not be able to stay clear entirely due to the presence of perfluorocarbons in groundwater. 

The shift in understanding of perfluorocarbons from harmless substances to potential cancer risks is significant because it so starkly underlines how much we don’t know about our chemical environments. Indeed, Dr. Crinnion’s warning from several years ago regarding perfluorocarbons is only one of several that he offered regarding poorly characterized environmental threats to human health. “If you’re living a standard American lifestyle, what does that do to your risk? We don’t know,” he said. “There have been very few studies examining multiple factors because that doesn’t work with scientific theory well.” This means that chemicals that appear to be safe in isolation might, in fact, be harmful when synergistically paired with other common substances—a daunting prospect for any health-conscious member of the public.

Using Environmental Medicine To Protect Public Health

Dr. Crinnion’s overarching message from several years ago is still clear: people need to be aware of the chemicals in their environment, and they can’t expect the government to tell them what is safe and what is not. Pointing to the regulatory fiasco surrounding the U.S. Government’s failure to timely ban the pesticide chemical chlorpyrifos, Dr. Crinnion’s skepticism then appears more salient now than ever. Despite a long history of well-documented negative health impacts on adults, children, and fetuses reaching as far back as 1999, as recently as 2017 the U.S. EPA declined to ban chlorpyrifos in contradiction to the standards established previously by the World Health Organization. 

Although the U.S. Government’s federal courts ultimately issued an order to the U.S. EPA requiring them to ban the chemical in late 2018, until that point consumers could purchase household pesticides containing chlorpyrifos. This means that nearly 20 years after chlorpyrifos was first identified as causing autoimmune disorders and dysexecutive syndromes in children, Americans were still in harm’s way due to their government’s unwillingness to act on the evidence. 

If banning even the most dangerous environmental contaminants can take decades when the data are unambiguous, what should the public do when the safety data are less clear or totally absent? Given that there are far too many unknowns regarding the chemicals people interact with every day, mere vigilance regarding new findings might not be enough to protect people. Recognizing this, Dr. Crinnion sought to ward off fatalism in the public by providing a set of best practices regarding environmental health.

First among these is removing that which is known to cause harm. Whether by avoiding products containing plasticizers that are endocrine disruptors or by installing filtration devices in the home to prevent inhalation of ambient contaminants, the public stands to be empowered by following Dr. Crinnion’s still timely advice closely.

To protect health in the face of ambiguous, unknown, or unavoidable threats, Dr. Crinnion advocated making the most out of the things that science knows to be healthy: eating vegetables, spending time in the sun, and getting plenty of exercise. However, performing normal health practices is not enough to provide total protection from environmental hazards, particularly when many of those hazards are not yet fully understood. As such, many individuals are interested in proactively providing themselves with a measure of prevention beyond the basics of healthy living. 

For them, Dr. Crinnion suggested incorporating a number of nutritional supplements to improve the body’s ability to maintain normal function in the face of toxins.* Especially for individuals with a compromised immune system or an autoimmune disease, a science-backed nutritional supplement regimen could make the difference between chronic illness issues and long-term health and wellness. 

The greatest value of environmental medicine comes from the way it enables the individual to take personal initiative against environmental threats. In the second half of the interview with Dr. Walter Crinnion we will learn more about protecting oneself from environmental toxins and implementing what Dr. Crinnion called the “holy trinity” of sound environmental medicine practices in your home. In the second half of his interview, Dr. Crinnion also disclosed the nutritional supplement he considered to be the most promising for the purposes of environmental medicine, explaining how it can combat the negative impact of the number-one most destructive environmental contaminant: vehicle exhaust.    

The power of Tesseract supplements lies in enhancing palatability, maximizing bioavailability and absorption, and micro-dosing of multiple nutrients in a single, highly effective capsule. Visit our website for more information about how Tesseract’s products can help support your neurological health and more.*

Works Cited

Aungst J, Anderson S. 2014. Food and Drug Administration Department of Health and Human Services. 

Center for Disease Control, Environmental Health Division. 2009. Phthalates fact sheet

Crinnion WJ. 2018. Crinnion Opinion. http://www.crinnionopinion.com/

Crinnion WJ. 2000. Alternative Medicine Review. 5(1):52-63

Desvergne B, Feige JN, Casals-Casacs C. 2009. Molecular Cellular Endocrinology. 304(1-2):43-48

Engel SM, Villanger GD, et al. 2018. Environmental Health Perspectives.126(5):057004

Food and Drug Administration. 2018. Department of Health and Human Services

Grandjean P, Clapp R. 2014. Public Health Reports. 129(6):482-485

O’Connor JC, Chapin RE. 2009. Pure and Applied Chemistry. 75(11-2):2099-2123

Palanza P, Gioiosa L, vom Saal FS, Parmigiani S. 2008. Environmental Research. 108(2):150-157

Rebuli ME, Cao J, Sluzas E, et al. Toxicology Science. 140(1):190-203.

Rochester JR. 2013. Reproductive Toxicology. 42:132-155

Rudel RA, Perovich LJ. 2009. Atmosphere and Environment. 43(1):170-181

Al Czap, Founder | Tesseract

Al Czap has more than four decades of professional experience in preventative medicine. He founded Thorne Research in 1984 (sold in 2010) and he published Alternative Medicine Review for 17 years beginning in 1996. AMR was a highly acclaimed, peer-reviewed, and indexed medical journal. Al was the first to recognize the need for hypoallergenic ingredients and to devise methods of manufacture for and delivery of hypoallergenic products to underserved patient populations. His work has greatly impacted those with impaired immune and digestive systems and compromised health due to environmental exposures.

The advanced formulations based on our revolutionary, patented, and patent-pending technology are only available through Tesseract. No other medical, pharmaceutical, or supplement company is licensed to utilize our proprietary technology.
*These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure, or prevent any disease.
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