Most people, and many regulatory agencies believe, that something is either a poison or it is not. The study of poisons is called “toxicology” and even the founding father of toxicology had a different view. Paracelsus (1493-1541) said that all things are poisons, whether you are poisoned depends on how much you consume. Interestingly, some things that are poisonous are also helpful as the Godfather of Hormesis (a part of toxicology), Ed Calabrese would tell you.
For example, in medicine we inoculate people with small doses of chemicals that, in larger doses, makes them sick or kills them. It has been known for centuries that a little bit of snake venom administered over time can help protect you from a large injection from a poisonous snake bite. Similarly, if you exercise, some is good for you but, if you go way overboard, it can be disastrous. The same is true of water, food, and vitamins. Some amount is good for you but too much, particularly too quickly, can kill you.
This phenomenon, where at a low level something is good for you, but a higher level is bad for you, is called “hormesis.” This term comes from a Greek word that means “to set in motion.” Although it is a general principle (although we don’t know if everything has a hormetic dose), it is personalized. That means that the level at which something becomes a poison to me may be different than the one that may cause it to be a poison to you. For regulations, depending on the dose, a regulatory level of exposure may be helping some but hurting others. The same thing is true for medicines and foods. That’s why we are moving to personalized medicine and nutrition. Perhaps personalized toxicology is next.
Generally, there are three levels of poisons: high levels at which something becomes poisonous, levels at which nothing happens (thresholds), and low levels at which a chemical affects you positively. Since it’s harder to detect the positive effects at the lower levels (because the response is usually modest), it makes it more difficult to discover those levels. In addition, what we call “beneficial,” such as increased growth, may also not necessarily be beneficial.
Rejecting the idea of thresholds and hormetic levels, i.e., belief that a chemical that causes a lot of cancers at high doses will cause fewer cases of cancer at lower doses, is called the “linear, no threshold” theory. It is the theory most commonly used today in courts and regulatory agencies and it’s probably the way most people think – a poison is a poison.
But when you read an example about the presence of a carcinogen, like pesticides on strawberries, you may be reading about a level that is extremely small, like a drop in a lake. In fact, with modern detection methods, we can detect microscopic levels of chemicals in just about anything. At those levels, it can be either at the threshold level or a hormetic level.
In fact, it’s not just chemicals. People tend to believe that any dose of radiation is bad for you, but small amounts are good for you (again, hormesis).
Trying to prove that it is not the case that there is harm at every level, much less good at low levels, has been difficult. Ed Calabrese, who has done more on hormesis than anyone else, recently looked at a radiation study from decades ago. In the study (1956 to 1959), the authors from Oak Ridge National Laboratory examined a very high dose of radiation (600 rads) given to mice and found no effects on either longevity or cancer (although there are negative human health effects at this level). They didn’t publish the study as they were wedded to the poison at any dose theory.
Some regulatory agencies won’t even acknowledge hormetic effects. A Google search on “hormesis” turns up 2.26 million papers, but a search on the U.S. Department of Energy’s website turns up zero – “no results found.” Stay tuned, the Health Physics Society is doing a documentary (15-20 episodes) on Ed’s work and it should be fascinating for those who are interested in such matters.
Meanwhile, if you are told that a pesticide is found at microscopic levels on a strawberry, don’t stop eating it; and don’t refuse an X-ray when it is necessary. A poison is not always a poison.