A Bad News Profession

Pharmaceutical Toxicology

Pharmacology and toxicology have a shared history.  The division is quite natural.  The desirable effects of a drug are studied by a pharmacologist, while the undesirable effects are studied by a toxicologist.  So, not only are Pharmacology and Pharmaceutical Toxicology (pTox) concerned with the same set of chemicals, a student of pTox will study the same courses as the Pharmacologist, and probably get the same degree from a department that is typically associated with a medical school.   The Pharmacology program will have more emphasis on medically desirable effects, while the pTox program may have a little a more emphasis on pathology, but that’s about it.  

As a profession, pTox is associated with the pharmaceutical industry.  The three main employers for pToxicologists are the drug industry, the U.S. Food and Drug Administration (FDA) which regulates the drug industry, and academia.  Most research on the toxicology of drugs is sponsored by the pharmaceutical industry.  However, the FDA does have a small institute called the National Center for Toxicological Research (NCTR) that does some basic research on drug toxicology.   

The other thing about pTox is that just about everyone knows drugs can be toxic.  That is why drugs are prescribed with specific dose recommendations and they typically come with a list of potential side effects.  Because toxic effects are not especially rare, pharmaceutical toxicology is largely an empirical science where theory has a limited role.  It is also why the FDA must consider both safety and efficacy when deciding whether or not a drug should be approved: As long as the disease that is treated by the drug is worse than the side effects, then it is a good drug; otherwise, it isn’t.   Bad news is OK, as long as the good news is better.

Environmental Toxicology

The other main flavor of toxicology is Environmental Toxicology (eTox).  Although eTox barely existed when the Society of Toxicology was founded in 1961 years ago, it is the dominant face of toxicology now.  It more or less began with the publication of Silent Spring in 1962 (Carson, 1962).  Even though they didn’t exist at all even thirty years ago, there are far more graduate programs in eTox than pTox now.  Degree programs for eTox are typically associated with either Public Health Departments or Environmental Studies Programs.  

As a profession, eTox is associated with the pesticide and chemical industry.  The main employers for eToxicologists are the U.S. Environmental Protection Agency (EPA) which regulates the pesticides and chemicals, state public and environmental health departments, academia, and the chemical industries that make both pesticides and industrial chemicals.  While some research on environmental chemicals is sponsored by the chemical industry, eTox research is mostly funded by the federal government, primarily through the EPA and the National Institute of Environmental Health Sciences, which both conduct their own research and fund research at academic institutions.

When the EPA was founded in 1970, the main goal was to protect the environment from humans.  However, the EPA is more widely thought of as a Public Health Agency that is responsible for protecting humans from the environment (Goldstein, 1988), which means eTox shares an interest with pTox in human toxicology.  However, compared to drugs, the chemicals that are the concern of eTox are far less toxic, at least to humans anyway. Pesticides, of course, are generally used precisely because they are toxic to things in the environment (e.g. weeds, fungus, insects, and rodents).  Therefore, the usual concerns are rare long term effects that may occur, instead of short-term effects that do occur.   This makes eTox more theoretical, and less empirical than pTox.  Also, with the exception of the occasional potentially toxic metal that is also an essential nutrient, there is no need to balance the toxicology against other health effects.   That means the only good news for an agency risk manager is no news.   On the other hand, when justifying a research proposal, bad news can actually be good news (Franklin, 1994).

Food Toxicology

Along with clinical toxicology and forensic toxicology, food toxicology is a small field.  It is only worth mentioning for two reasons.  First, the procedures commonly employed for the regulation of chemicals in the environment have historical roots in the regulation of food. Second, that is mainly what this blog is about.  There is nothing about food toxicology that substantially differentiates it from pTox or eTox, so there is little reason to employ fTox as an abbreviation.  However, the toxicology of different classes of chemicals in food can be like pTox, eTox, or somewhere in between:

• Food additives are not very toxic at all, and are pretty much regulated just like pesticides.  So, food additive toxicologists are quintessential eToxicologists.  
• Many dietary supplements really are drugs.  In fact, some of them are psychoactive drugs, where whether or not the effect is desirable or adverse largely depends on your point of view.  
• Unintentional contaminants like lead, arsenic, cadmium, and methylmercury generally only attract attention only because they are known to be toxic, and as a result, their study is little more like pTox-like than the food additives.  

There are a few toxicology programs that are specifically concerned with food, but not many.  They are most likely to be found at land-grant universities that have a strong interest in agriculture.  

Even though the food industry is far larger than either the drug or chemical industries, they don’t employ very many toxicologists.  However, since they must sponsor the studies required for approval, chemical companies that make food additives do.  So do federal and state regulatory agencies concerned with food safety, including the FDA and the U.S. Department of Agriculture.   The federally sponsored research budget for chemicals in food is not large, but NIEHS, NCTR, and the USDA all sponsor some research, with mycotoxins (toxins produced by fungi) being the usual culprit.  Also, there is a substantial overlap between contaminants in the environment and contaminants that occur in food, so a toxicology study on arsenic is applicable no matter where it is found.

Pharmaceutical toxicologists rarely use words that signify the lack of bad news like “safe” or “protect”.  That’s just not what pToxicology is about.  If they do, “safe” clearly just means “safe enough”.  On the other hand, eToxicologists use those words all the time.  So do most food toxicologists, especially the ones who work on food additives.  That is entirely understandable, because that’s exactly what their job is: A chemical cannot be used unless they say it is safe – that’s what the law says.  But, count me out.  I’m a pToxicologist who has worked on contaminants at the FDA for over 25 years.  Nobody has ever asked me for permission to add arsenic, cadmium, lead, or methylmercury to food, and I know full well how the bad news has a way of slipping out.

References

Carson, R (1962).  Silent Spring.  Houghton Mifflin

Franklin, J (1994).  Poisons of the Mind.  J Animal Sci 75:68-74

Goldstein BD (1988).  EPA as a Public Health Agency.  Reg Pharm Toxicol 8:328-334
Society of Toxicology.  Academic and Postdoctoral Toxicology Programs and Websites

Official Post Soundtrack

Green Day (2000).  Warning.  In: Warning, Track 1.

Post Note

This is Thesis Post #9.  It is also the first post of a new thread that is mainly concerned with Regulatory Toxicology