We are all exposed to thousands of chemicals every day. How much of a risk does this present?

I have reached the age where my family doctor, looking at my family history, recommended I undergo a specific examination. This particular procedure required me to consume only clear liquids for a day, followed by a purgative with packaging that essentially warned me “do not leave your home.” Thinking optimistically, I decided to consider it research: My first goop-worthy cleansing and “detox”. I’m probably loaded with toxins. I don’t buy organic, I don’t wear gloves when I handle receipts, I still use an old Nalgene water bottle, and I’ve never had a good “cleansing”. Would I achieve the enlightenment and wellness that detox and cleansing advocates promise? The reality was much less pleasant: just cramping and food cravings. It took a few days before I felt back to my (presumably toxic) self.

Why would anyone choose this discomfort voluntarily? It’s because many believe that we are contaminated with chemical and various harmful substances, and that by “detoxing” our bodies (usually starting with our colon) through different types of rituals, we can reduce or eliminate various toxins.

It seems every few days there’s a new story in the media raising alarm about the risk of chronic exposure to some sort of chemical. It sounds at least plausible, because in some cases, it is true: Fish consumption warnings, like the sign above, are commonplace today, and reflect the fact that we have collectively poisoned parts of our food supply. But worries that we’re being poisoned by toxins go well back in history, before the time humans were putting mercury and PCBs into the environment. One of the oldest surviving written documents is an Egyptian papyrus from the 16th century BCE that linked the cause of disease to digestive wastes in our colon, suggesting that these types of fears may be innate. Since that time, our scientific knowledge about the cause of disease has advanced, but the underlying obsession with diet, elimination, and toxins hasn’t waned. Part of the modern appeal of “detox” may be that detoxification is a legitimate medical term and treatment. While it is used regularly in reference to the acute treatment of substance-use disorders, it’s also a term that may be used when managing acute poisonings and other toxicological emergencies. Alternative health advocates have embraced the word and the concept of detoxification, but skipped the need for good science and evidence, as they promote countless strategies and products around this nebulous idea of “toxin removal”.

Alternative medicine’s ideas of detoxification

“Detox diets” and “detox kits” are dietary interventions that are claimed to support or promote the elimination of toxins. They are often simultaneously marketed at weight-loss strategies, although they are routinely promoted to those without any weight or health problems whatsoever. Detoxification strategies are very popular with alternative-health providers such as naturopaths. A 2011 online survey of naturopaths noted that 92% of naturopaths claimed to use “clinical detoxification strategies”, with clients starting in infancy, and continuing through adulthood:

Detoxification therapies reportedly used by more than 75% of NDs [naturopaths] included dietary measures (cleansing foods, increased fruit/vegetable intake, vitamin/mineral/antioxidant supplementation, organic foods, elimination diet, stool bulking agents/fiber), probiotics, reducing environmental exposure, and cholagogue herbs (herbs that promote the excretion of bile).

Britt Marie Hermes was once a naturopath that promoted the alternative medicine view of detoxification to her clients. In her post “The Anatomy of a Detox Scam,” Hermes (who subsequently quit naturopathy, and is now its harshest critic) described how she invented a detoxification scheme she called The Right Detox:

Detox programs are created with one goal: make money. I am not generalizing here. I’ve helped create detox programs at more than one clinic. In each instance, the decisions to include specific detox supplements, protein powder shakes, or therapies were based on profit margins. Detoxers doing The Right Detox could purchase different “tiers” of the program. The scheme was simple. The “deeper” the detox, the higher the tier, and the more expensive the package.

Like all other over-the-counter or alternative medicine detox plans, there is a lack of robust evidence to show that these types of detox strategies do anything at all.

While naturopathic and alternative medicine’s ideas of detoxification have no solid grounding in science, it’s fair to ask if there’s anything science-based to the general concerns about chronic chemical exposure toxicity. Fortunately, there is some evidence to inform our decisions.

What exactly is a toxin?

The word “toxin” is used casually in alternative medicine and the popular press. Gluten came from nowhere to be seen as some sort of toxin, now seemingly replaced by sugar as the toxin du jour. Fat used to be a toxin. Now it’s carbs. And salt. (Or salt is OK now). Some claim genetically modified organisms (GMOs) are toxins (they aren’t). The CDC uses the following definition:

Toxic agent: Chemical or physical (for example, radiation, heat, cold, microwaves) agents that, under certain circumstances of exposure, can cause harmful effects to living organisms.

There are legitimate reasons to be concerned about our exposure to toxic substances. From radon in our basements to lead in our drinking water, there are many chemical substances we may be exposed to that have the potential to cause serious harm. And it is true that industrialization and modernization have increased the number of synthetic chemical substances that we may be exposed to. It is also true that some substances can accumulate in the body, and have the potential to cause harmful effects. The ability of any particular substance to cause harm will be affected by that substance’s action in the body, which will be influenced by out body’s innate detoxification systems, provided mainly through the liver and kidneys.

The extent to which any substance may be toxic can be influenced by the route of exposure (e.g., inhaled asbestos fibres can cause mesothelioma), the dose, which is the amount in the body (e.g., acetaminophen is safe at low doses but highly toxic in overdose), and the length of exposure, where chronic or long-term exposure may create a different toxicity profile than short-term exposure. Not everyone will react to a chemical in the same way. Genetics, age, and other factors can influence how substances we are exposed to are metabolized or eliminated.

Concurrent with our growing awareness of our environmental exposure to thousands of substances has been the advancement of analytical testing methods that allow the identification of these substances at vanishingly low concentrations. We can now verify that human tissue or breast milk may contain substances like persistent organic (carbon-based) pollutants (POPs). While this may sound concerning, we need to acknowledge that their identification does not automatically mean that they are causing us harm.

In the United States, the National Toxicology Program (NTP) coordinates research across different federal agencies and evaluates the effects of chemicals on health. The NTP has a detailed report of 248 products or substances known to cause, or anticipated to cause, cancer. However, the NTP notes:

There are tens of thousands of chemicals in the world that we know very little about. Only a small number of chemicals have been assessed adequately for potential toxicity to humans.

There is no scientific consensus on whether chronic very-low-dose exposure to substances like POPs is harmful to human health. And it is this uncertainty (and fear) that has bolstered the current alternative-health detoxification market. Preying on these innate fears of “poisoning from within”, the industry promotes the view that any exposure, no matter how slight, is harmful, and that alternative-medicine detoxification will help. Many detox diets and diet kits claim to remove unspecified “toxins” from the body. Other approaches promoted claim to bolster the ability of organs like the liver to work more effectively. However, few if any actually name the specific toxins that are removed, or provide evidence that toxins are actually removed as a direct consequence of the detox process recommended.

Cause for concern?

Should we be concerned about the chemicals we are exposed to in the environment? Last month David Gorski noted how alternative medicine has latched on to the idea of “obesogens” in the environment as a contributor to the increasing prevalence of obesity, when the evidence itself seems far less convincing.

Similar claims have been made about pesticides – particularly the residue that on food. As Harriet Hall has noted, the Pesticide Data Program of the USDA monitors food residues, focusing on those products consumed by infants and children. The 2016 results were reassuring:

  • Again this year, the PDP results shows that the U.S. food supply is one of the safest in the world. The PDP testing methods detect the lowest possible levels of pesticide residues, including levels below the EPA established tolerances.
  • In 2016, surveys were conducted on a variety of foods, including fresh and processed fruit and vegetables, eggs, and milk. The report includes data from over 10,000 samples collected in a variety of States and throughout the year ensuring the samples are representative of the entire United States.
  • Over 99 percent of the samples tested had residues well below the EPA established tolerances. The results also showed more than 23 percent had no detectable pesticide residue.
  • Samples with residues exceeding the EPA-established tolerance were found in 0.46 percent (48 of 10,365) of the samples, and 2.6 percent (273 of 10,365) of the samples had residues with no established tolerance for the specific commodity tested. For eggs and milk, there were no residues found that exceeded the tolerance levels, nor were there any residues with no established tolerance.

There’s a lack of evidence to suggest that the synthetic pesticide residues found in food are at levels that have negative health effects. Bruce Ames published a now-famous and widely-cited paper on pesticides back in 1990 that concluded that almost all of the pesticides we eat are “natural”, and that few of them have ever been tested for harm:

We calculate that 99.99% (by weight) of the pesticides in the American diet are chemicals that plants produce to defend themselves. Only 52 natural pesticides have been tested in high-dose animal cancer tests, and about half (27) are rodent carcinogens; these 27 are shown to be present in many common foods. We conclude that natural and synthetic chemicals are equally likely to be positive in animal cancer tests. We also conclude that at the low doses of most human exposures the comparative hazards of synthetic pesticide residues are insignificant.

Finally, if there could be “one true cause” of toxicity it has to be endocrine disruptors (e.g., bisphenol A), synthetically-produced chemicals that mimic naturally-occurring hormones in the body. As the products are now ubiquitous in our environments, there are understandable questions about the health effects of this chronic exposure. Summarizing all of the evidence is beyond the scope of this post, but it’s fair to say that the evidence is unclear, with some regulators taking steps to reduce potential exposure to infants and children as a precaution.

Summing up

Technology’s progress has allowed us to detect our exposure to chemicals with remarkable sensitivity. While there is evidence supporting the claim that there are synthetic and other environmental toxins in humans and in our food supply, there is a lack of evidence to show that (with some exceptions) there is specific cause for concern. Serious toxicity and poisonings are managed in hospital emergency rooms: That’s where the only effective detoxification interventions occur. Detoxification ideas promoted in the popular press, including anything sold as a kit or diet, or promoted by alternative medicine practitioners, lack evidence they do anything beneficial at all. The best evidence we have for reducing the risk of disease may be to do things we already know: eat a balanced diet, move as much as possible, keep alcohol consumption as moderate as possible, and don’t smoke.

Photos from flickr users Don McCullough and Jorge Franganillo, used under a CC license.


Posted by Scott Gavura