Why does a shower curtain get sucked in when we’re taking a shower? How do two-in-one shampoos work? If nothing sticks to Teflon, how do they get it to stick to the pan?
These are the typical kinds of questions I used to get. But my, oh my, how times have changed.
These days a question about shower curtains is likely to be about the release of phthalates, with shampoos about the presence of parabens, and as far as non-stick cookware goes, I’m more likely to get sticky questions about health risks than cooking properties. In general, questions tend to be in the how-much-should-I-worry-about category. Depending on what’s in the news, the concern may be over fire retardants in upholstery, drug residues in drinking water, formaldehyde in bras, diisocyanates in mattresses, bisphenol A in canned food, trichloroethylene in groundwater, dioxins in meat, mercury in vaccines, pesticide residues in food or radiation emanating from granite countertops. Curiosity about what we can do with chemicals has been replaced by fear of what chemicals can do to us.
All of this is very understandable, given that loss of health is our greatest fear in life. So, what can we do to prevent illness?
Lifestyle factors such as proper nutrition, weight control and exercise are important. We also know that radiation, cigarette smoke and occupational exposure to certain chemicals can have a negative impact on health. But, until recently, not much attention has been paid to exposure to the tiny amounts of chemicals that show up in the environment as a result of chemical innovations introduced since the Second World War.
Thousands of chemicals that never existed before are now produced in dazzling amounts, and they sometimes show up in unexpected places – like our bodies. Almost daily, media reports alert us not only to the presence of these chemicals, but to their potential for undermining our health.
Why is there so much interest in these environmental contaminants of late?
There are several reasons. First, we used to have bigger fish to fry. When you are concerned about improving food production, controlling malaria or battling infections, you tend not to sweat the small stuff – especially if you don’t even know that the small stuff is there. Now, thanks to recent advances in technology, we know. Of course, it was always reasonable to suspect that our massive chemical production must leave some sort of environmental footprint, but we didn’t worry much because of our reliance on the mantra of toxicology: “Only the dose makes the poison.” We assumed that if we couldn’t detect it, it couldn’t be doing any harm.
Times have changed. Chemicals can now be detected at levels of parts per trillion, or sometimes even lower. And we have accumulated evidence that some – especially those that can mimic the effect of hormones – can produce physiological effects at such incredibly small concentrations.
There is something else that we now have: much better information about disease incidence and disease patterns. Rates of childhood cancer have increased since the 1950s, as have prostate and breast cancers, both of which have a hormonal connection. Some of the increase undoubtedly can be attributed to better diagnostic techniques, but something else seems to be going on as well.
The question is what?
There are experts aplenty who claim to know the answer, but the problem is they all have different answers.
Research these days has become very specialized.
Scientists who study the effects of bisphenol A released from plastics, for example, may know nothing about the work being done on phthalates or on brominated diphenyl ethers or on beryllium or on electromagnetic radiation.
Indeed, they may not even be aware of the existence of these fields of research. They live in separate worlds, the only common feature being the presence in each of these worlds of scientists, physicians or self-proclaimed experts who claim that our health problems are caused by their pet culprit. You can take your pick from plasticizers, dioxins, chlorates, air particulates, perfluorooctanoates or a slew of others.
Since we are exposed to most of these to some extent, if the claims of harm were all true, we would be dropping like flies.
Of course, this is not to suggest that such environmental contaminants cannot have an effect on our health. Almost surely they can.
But teasing out which ones, and under what conditions they may cause harm, is a daunting task, with many possible pitfalls. For example, a type of rat, known as the Sprague Dawley, is commonly used to evaluate compounds that may either mimic or block the activity of natural hormones. This rodent, though, has been bred to reproduce in a prolific fashion, and has a hormonal constitution that may be more resistant to endocrine-disrupting chemicals. Probably not a good model for humans.
Any alteration in the genes that make up DNA upon exposure to a chemical is also a basis for determining toxicity, but we now know that certain chemicals can significantly affect the functioning of DNA without altering its structure. The burgeoning field of epigenetics deals with the notion of chemicals turning genes on or off without affecting their structure. A chemical, such as bisphenol A, may for example deactivate a gene that codes for the production of a protein that helps protect a cell from cancer. Epigenetic research will probably be able to help focus our worries.
So what is the point of all of this – it’s far more complicated to answer questions about health than about the behaviour of shower curtains? As for individuals who think their pet toxin is responsible for all of society’s ills, well, they could use a cold shower.
And for me, my worry is that I’m not sure what to worry about. I don’t think worrying about everything is the answer.