People used to think the skin was an impenetrable barrier, blocking anything from entering (or exiting) the body. After all, if it wasn’t, we wouldn’t be able to take a shower without bloating up with water, right?
Now we know better. Skin does provide a barrier to the world, but not an impenetrable one. Stay in the bath long enough and you’ll see-skin absorbs water to a certain extent, which is why it wrinkles.
“Your skin is enough of a barrier to keep fluids within your body,” writes Samuel Epstein, MD, and author of Toxic Beauty (BenBella Books, 2009), “but it also readily absorbs many things with which it comes in contact.”
Whether or not the skin will absorb something depends on a lot of factors, including the substance itself, the health of the skin, site of exposure, temperature, hydration of the skin, even how hairy the skin is. One study showed that hairier skin, because of its increased number of hair follicles, absorbed more benzoapyrene (BP-a suspected human carcinogen) than hairless skin. Testosterone, however, penetrated both types of skin equally. (These studies were conducted on mice, which according to other studies, have a skin-absorption rate more than 3-fold higher than human skin, so human skin absorption levels could be lower.) But though scientists still can’t pin down exactly how much or under what circumstances skin may absorb something, they all agree that it can absorb what is applied to it.
“Chemicals can be absorbed through skin and into the blood stream, causing toxic effects,” says the Extension Toxicology Network (EXTOXNET). The Chemical Hazards Handbook from the London Hazards Centre Trust has similar information: “Although the skin acts as a protective barrier against many micro-organisms and chemicals, some chemicals can penetrate the skin and enter the blood stream.” Researcher Linda Chaé, writing for thehealthytruth.net, agrees, citing the danger to unborn children: “Recent studies by dermatologists at the University of California and a multiple university cooperative team confirm that skin absorption is the major route of entry [for chemicals from skin or hair products getting into the womb].”
Beyond the fact that skin can absorb chemicals is the danger those chemicals pose in the body. Many experts agree that absorption through the skin is more dangerous than through the mouth. Substances absorbed into the digestive system go through the kidneys and the liver where enzymes break them down and often detoxify them, whereas substances absorbed through the skin go through no such process. “Chemicals taken in by the mouth are absorbed by the intestines and pass into venous blood, which is taken to the liver,” Epstein says. “Carcinogens absorbed through the skin bypass the liver and enter blood circulation without this protection.”
Though we still don’t know for sure what percentage of the chemicals we put on our bodies everyday is absorbed into the blood stream, the fact that it happens should be enough to motivate us to be more careful. For your health and the health of those you love, look at your skin in a different way-when you put something on it, imagine that substance inside your body. Would you feel as comfortable using it? If not, try something else instead-something with more wholesome, safe ingredients you can feel good about.
Realizing your skin is permeable, have you made changes in your skin-care routine? Please share your experiences.
Photo courtesy madelien via Flickr.com.