Dose Makes the Poison: The Science Behind Relevant Exposures

Jonathan Freedman, PhD (Head of Science at EXPIN)

What is there that is not poison?
All things are poison and nothing (is) without poison.
Solely the dose determines that a thing is not a poison

Abstract image of a poisonous mushroom

This 16th century quote by Swiss physician and alchemist Paracelsus is still the core of modern toxicology. Less poetically written, everything is toxic if you are exposed to enough of it. This also implies that even if you're exposed to something toxic, you are not guaranteed to get sick. For example: the botulinum toxin in Botox is considered the most lethal biological substance known. Two hundred nanograms (0.0000002 g) will kill an average man. Less than 1 nanogram (0.000000001 g) of the same substance however, will remove those fine lines from your face or help prevent migraine headaches.

Social media and mainstream news headlines often forget this basic idea when discussing exposure to (potentially) toxic chemicals. For those living with Hashimoto’s disease and other autoimmune diseases, blogs and social media comments are replete with warnings about how a particular food or specific chemical will cause symptoms. Oversimplified summaries will take a scientific finding such as: “There is a statistical association between flame retardants and the occurrence of Hashimoto’s disease” and re-express it as: “Flame retardants, which are found in all clothing, cause Hashimoto’s disease.” You may be exposed to flame retardants, but at such a low level that it’s irrelevant to your health. On the other hand, social media posts advocate mega-doses of over-the-counter nutritional supplements, vitamins and minerals. While these are intended to improve health or alleviate symptoms, too much of any nutritional supplement taken under blanket guidance can also present health complications.

What’s the science behind toxins in the news?

The Headline	The Science	The Mishap	What It Means
Coffee in California Will Soon Come with a Cancer Warning	Acrymalide is a chemical that’s produced when sugars and amino acids are cooked at high temperatures, including during the coffee bean roasting process. It’s been shown to cause cancer in rats at high doses, which suggests it could have the same impact on humans.	California has a zero tolerance policy for any carcinogen, so coffee does come with a warning there. But in practice, not every carcinogen is built the same or equally prevalent. According to testing by the Clean Label Project, one cup of coffee contains roughly 1.77 micrograms of acrymalide, compared to 75.65 micrograms in a serving of french fries from a fast food joint.	Acrymalide is something to pay attention to, but trace amounts in coffee are unlikely to be the problem, especially when so many other commonly consumed foods contain greater doses of the poison. Cigarette smoke is the most concentrated and relevant source of acrymalide for the general public.
Big doses of red wine could promote long life	In the mid-2000s, a buzzy Harvard study performed on 55 obese rats showed that large doses of resveratrol, an extract of red wine, improved overall health and performance on a skills test.	Headlines failed to note that to get the same benefits as these obese rats, a 150-lb human would have to drink roughly 750 to 1000 bottles of red wine…per day.	Resveratrol from a combination of foods or even supplementation could have a positive effect on anti-aging. But drinking endless amounts of red wine would cause cancer, high blood pressure, liver harm, and weight gain long before it would guarantee longevity.
The Great Black Plastic Spatula Panic	In 2024, a study published in the journal Chemosphere showed that black plastic cooking utensils leach about 34,700 nanograms of flame retardant BDE-209 into food. The study also correctly reported that the safe level of BDE-209 exposure is up to 7,000 nanograms per 1 kg of body weight.	Based on that safe level, Chemosphere calculated that for a person weighing 60 kg, the safe level of BDE-209 is 42,000 nanograms. This implied that many people come close to exceeding (or exceed) this safe limit with daily utensil use. But 7,000 x 60 isn’t 42,000 nanograms…it’s 420,000. This means the typical daily exposure to BDE-209 is less than 1/10 of the safe limit.	While avoiding plastic utensils and flame retardants in general is probably a good idea, this math mishap caused an outsized hysteria. When this study came out, one person even reported that the “entire city of Burlington, VT was throwing black spatulas out of their windows in unison.”

All of these examples fumbled the core principle that dose makes the poison — it was true for Paracelsus in the 16th century, and it’s true today.

How does EXPIN measure the importance of exposures?

EXPIN is designed to help you sift through the noise to find the exposures relevant to you on an individual level. Our scientific team understands that not every exposure you mention during your interview plays an equally important role in your disease. Some exposures are leading characters that likely drove your disease; others are background cast members that are present at certain times in your story, but not frequently enough to make an impact.

EXPIN maps the full picture of your life and health against scientific evidence about exposures. We prioritize two things when building your report: (1) the strength of scientific evidence about an exposure and (2) the relevance of that exposure to your story. In your report, we break down your main exposures against these criteria to help you understand their role in driving your disease.

For example, there’s strong evidence to show that a compound in cruciferous vegetables like broccoli, cabbage, and kale can interfere with iodine uptake. If you have Hashimoto’s or hypothyroidism and eat large amounts of cruciferous vegetables, your EXPIN report may suggest that you discuss that diet with your physician. In contrast, if you eat broccoli just once a week, your EXPIN report will inform you that your consumption of cruciferous vegetables should be limited, but that you don’t need to worry about this exposure because of its infrequency in your diet. (And on that note, steaming, sautéing, or boiling cruciferous vegetables can help deactivate and reduce their iodine-disrupting compounds.)

When you’re searching for the answers behind your disease, we understand that sifting through scientific evidence can feel tedious and difficult to apply in practice. EXPIN’s mission is to make peer-reviewed research relevant at the individual level so you can take action against the “poisons” impacting your life, while worrying less about the ones that aren’t.

See how EXPIN maps your exposures →