Scary e-mails circulating on the Internet claim everyday objects, such as plastic and deodorant, are secret cancer causes.
Beyond being wrong, many of the myths passed on through forwarded e-mails may cause you to worry unnecessarily about your own health and the health of your family.
Before you panic, take a look at the facts. Here, Timothy Moynihan, M.D., a cancer specialist at Mayo Clinic, Rochester, Minn., takes a closer look at some popular myths about cancer causes and explains why they just aren't true.
Myth No. 1 -Antiperspirants or deodorants can cause breast cancer.According to the National Cancer Institute (NCI), there's no conclusive evidence linking the use of underarm antiperspirants or deodorants with breast cancer.
Some reports have suggested that these products contain harmful substances that can be absorbed through the skin or enter the body through nicks caused by shaving. According to the NCI, some scientists have also proposed that certain antiperspirant and deodorant ingredients called parabens may be associated with breast cancer because they're applied frequently to an area next to the breast.
Two studies of underarm antiperspirants and deodorants and breast cancer have provided conflicting results:
In 2002, a study involving 1,606 women evaluated the possible relationship between breast cancer and underarm antiperspirants and deodorants. This study showed no increased risk of breast cancer in women who used these products.
A 2004 study found parabens in 18 of 20 tissue samples from breast tumors. Parabens, which act like estrogen in the body, are preservatives used in antiperspirants and deodorants. However, this study didn't prove that parabens cause breast cancer. Also, the study didn't identify the source of the parabens. More research is needed to evaluate whether the use of antiperspirants or deodorants causes parabens to accumulate in breast tissue and whether these chemicals increase the risk of breast cancer.
Unlike lung cancer, for instance, where you see a steady rise in cancer rates when the smoking rate increases, there isn't a clear link between the use of antiperspirants and breast cancer. In the United States today, more than 90 percent of adults regularly use an antiperspirant or deodorant. But the breast cancer incidence rates and death rates for women haven't changed significantly since the 1930s—when, presumably, fewer people used antiperspirants or deodorants on a regular basis. For smoking and lung cancer there is a clear association—women began smoking in larger numbers in the 1940s, and lung cancer deaths rose significantly beginning in the 1970s.
Myth No. 2 -Microwaving plastic containers and wraps releases harmful, cancer-causing substances into food.According to the Food and Drug Administration (FDA), stories have circulated for years about the harm from chemicals in plastics leaching into microwaved foods. There is some evidence that substances used to make certain plastics can migrate into some foods. But the FDA has evaluated the migration levels of these substances and has found them to be well within the margin of safety.
The FDA carefully reviews the substances used to make plastics designed for food use, including microwave-safe plastic wraps and containers. These plastics are classified as "food contact substances." The FDA must find them safe for their intended use before these products can be marketed as such.
Other claims have suggested that plastics contain dioxins, a group of contaminants labeled as a "likely human carcinogen" by the Environmental Protection Agency. But according to the FDA, there is no evidence that plastic containers or wraps contain dioxins.
Myth No. 3 -People with cancer shouldn't eat sugar, since it can cause cancer to grow faster.Sugar doesn't make cancer grow faster. All cells, including cancer cells, depend on blood sugar (glucose) for energy. But giving more sugar to cancer cells doesn't speed their growth. Likewise, depriving cancer cells of sugar doesn't slow their growth.
This misconception may be based in part on a misunderstanding of positron emission tomography (PET) scans. Doctors use PET scans to help determine the location of a tumor and see if it has spread.
During a PET scan, your doctor injects a small amount of radioactive tracer—typically a form of glucose—into your body. All tissues in your body absorb some of this tracer. But tissues that are using more energy—exhibiting increased metabolic activity—absorb greater amounts.
Tumors are often more metabolically active than are healthy tissues. As a result, they may absorb greater amounts of the tracer. For this reason, some people have concluded that cancer cells grow faster on sugar. But this isn't true.
