I like to listen to the radio when I cook. And I was just in the midst of chopping my veggies when the lead item on the newscast caused my ears to perk up: “Carcinogenic chemicals found in baby shampoos!” I knew I had better get ready for the onslaught of phone-calls and the emails because the words “carcinogen” and “baby” in the same sentence add up to a formula for panic. But first things first. The chicken was already in the pot and I had to finish chopping my parsnips, carrots, onions and celery for the soup.
Once the soup was nicely simmering, I began to Google. The consumer group, Campaign for Safe Cosmetics, I learned, had commissioned a laboratory analysis of a number of children’s shampoos and bath products, and was now trumpeting the discovery of undeclared formaldehyde and dioxane. Since both of these chemicals are classified as probable human carcinogens, it comes as no surprise that the airwaves and newspapers were soon filled with stories about “baby products tainted with cancer causing chemicals.” What do I make of it all? Much ado about not much.
How do these chemicals end up in these consumer items in the first place? Formaldehyde is an indirect additive, released at a controlled rate from imidazolinyl urea, DMDM hydantoin or quaternium 15. Its purpose is to keep bacteria at bay. Dioxane is another story. This is a trace contaminant that is formed during the manufacture of certain detergents, such as those that may be included in baby shampoos and bubble baths. Concern arises because in addition to being likely carcinogens, formaldehyde and dioxane, are also potential allergens. Of course the pertinent question is whether or not the amounts found in these products present a risk. As we well know, dose matters.
As far as allergens are concerned, the dose that matters can indeed be very small. Some cosmetic products may contain up to 600 parts per million of formaldehyde, and that can cause skin irritation. Such reactions are rare, but possible. But reactions to bacterial contaminants that may form in the absence of preservatives are a bigger concern. It always comes down to a risk-benefit analysis. We don’t ban peanuts because allergy to them they may threaten the lives of some consumers.
People may accept the risk of an allergic reaction, but when the specter of cancer rears its head, well that’s another story. Indeed, formaldehyde can cause cancer, at least in animals that inhale it at a high dose over a long period. There is also some evidence that embalmers, pathologists and people who work with formaldehyde-containing resins may have a slightly increased risk of cancers of the lungs, nose and throat. But these exposures are astronomically greater than that presented by products such as shampoos which are applied, and then washed away. Even when formaldehyde is applied to the skin of mice at concentrations of up to 10% over their lifetime, no effects on longevity are noted.
Dioxane, based on animal studies, is a carcinogen. When administered to rats in large amounts in their drinking water, it can cause cancer. However, studies carried out on people who have extensive occupational exposure to dioxane have not shown any increase in cancer rates. So why should we tremble at the trace amounts of dioxane in some cosmetic product, amounts which in any case evaporate almost immediately when applied to the skin? We shouldn’t. But what about the possibility that tiny amounts may be absorbed through the skin and build up in the body? That seems to be very unlikely. A study of over 2000 people of all ages, randomly selected, has failed to detect any dioxane in their blood. So what’s our bottom line? Exposure to trace amounts of formaldehyde or dioxane from cosmetic products is not a big worry. If you’re going to get all antsy about such things, you might as well worry about, well, chicken soup!
That’s right. My chicken soup is loaded with carcinogens. Not man-made additives, but naturally occurring compounds. Furocoumarins like 8-methoxypsoralen are present in parsnips and celery. Not only are they potential carcinogens, they can cause nasty skin reactions. Carrots contain caffeic acid, another carcinogen. I commonly add basil, which contains estragole, a known rodent carcinogen. The same can be said for alpha-methylpyrroline in black pepper. I’m sure an analysis of my cooked chicken would reveal some heterocyclic aromatic amines, nasty carcinogens. And then there is the formaldehyde. It occurs naturally in the onions and shiitake mushrooms I use to flavour the soup. In fact, shiitake mushrooms, can have a whopping 400 parts per million of formaldehyde!
What is the point here? To trigger headlines about toxic chicken soup? Of course not. We need to realize that we are constantly exposed to thousands and thousands of chemicals on a daily basis, both natural and synthetic. Some, whether natural or synthetic, have the ability to trigger cancer under certain conditions. But the nature of those conditions is critical. The risk to an embalmer working with a concentrated formaldehyde solution day in and day out, or to a rodent reared on formaldehyde-laced drinking water, is not the same as that to a human exposed to traces of formaldehyde in a shampoo. And I don’t worry one bit about the formaldehyde I’m ingesting in my soup, even though I bet my exposure is far greater than from any shampoo.
If these notions drive you to drink, remember that alcohol is an established carcinogen. And if you would rather relax with a cup of coffee, well, then enjoy the acrylamide, chlorogenic acid and furfural, along with a host of other natural carcinogens.