by Carole Jackson, Bottom Line Health

 For many people, the thought of getting dressed without applying an antiperspirant seems downright unhygienic, not to mention antisocial. But a new review of research suggesting a link between antiperspirants and two deadly forms of cancer — breast cancer and prostate cancer — presents a theory that may change some minds.

 “Both of these cancers are hormone-dependent,” explains Kris G. McGrath, MD, associate professor of medicine at Northwestern University Feinberg School of Medicine and author of the review, which was published in Medical Hypotheses. He believes that the hormone problem may be located in the underarms and that antiperspirant use may be driving it.

 Two Similar Cancers

 According to statistics from the US National Cancer Institute’s Surveillance Epidemiology and End Results Program, the number of cases of breast cancer and prostate cancer in the US has been eerily similar throughout the 20th century, and for 2009 the figures are nearly identical — about 192,000 new cases of each. Dr. McGrath doesn’t think this is just a coincidence.

 Breast and prostate cancers share many characteristics. Both have hormone-dependent growth, in both cases primarily by sexual steroids. Women have a preponderance of circulating estrogen and very little testosterone, while it is the opposite for men — but estrogen and testosterone receptors are present in both breast and prostate tissue. Both cancers are treated with hormonal manipulation, and breast cancer is additionally treated with aromatase inhibitors to block the conversion of male hormones (androgens) to female hormones (estrogens).

 A possible cause

 Hormone-replacement therapy using synthetic forms of estrogen plus progesterone has been associated with breast cancer — but according to Dr. McGrath, rates of both breast cancer and prostate cancer started rising many years ago, well before the introduction of oral contraceptives and hormone-replacement. “So,” Dr. McGrath asked, “where are the hormones coming from? My hypothesis is that the problem started in the underarm after the introduction of aluminum salt-based antiperspirants in 1902.”

 In particular, Dr. McGrath is referring to the sweat glands located under the arm, which naturally release sweat, hormones and pheromones onto the surface of the skin. “When antiperspirants block these glands, the hormones they contain can’t leave the body,” he said. Instead, these hormones have the potential to be reabsorbed by the body — posing a potential excessive exposure to breast and prostate tissue. Even worse, antiperspirant use during puberty could be exposing breast and prostate tissue to unwanted hormones at a time of critical growth and development.

 Look at the label on your antiperspirant and you’ll probably see that it contains some form of an aluminum salt. These chemicals are used because they plug sweat ducts. The apocrine glands are considered an organ — by blocking them, “you are essentially blocking an organ and its function,” said Dr. McGrath. He added that antiperspirants are considered drugs by the FDA.

 A Better Alternative

 So what can we do about underarm sweating and odor without blocking the glands? Deodorants (as opposed to antiperspirants), which mask odors without blocking the sweat glands, can be a good option, but avoid products that contain petroleum-based propylene glycol, which is thought to be carcinogenic. (Propylene glycol derived from a vegetable source is fine.) Two deodorant brands he likes are the widely sold Tom’s of Maine (www.TomsOfMaine.com) and Terra Naturals (www.TerraNaturals.com). (Note: Dr. McGrath is a spokesperson for Terra Naturals.)

 Andrew L. Rubman, ND, our contributing medical editor, offered another suggestion for safely reducing the bacteria that cause underarm odor — good old baking soda. To use, mix about one teaspoonful of baking soda into enough warm water to make a thin, milky paste, which you then rub into your armpit. Or, he suggested, you can easily make your own totally natural, safe deodorant at home with just three ingredients: coconut oil, tea tree oil and lavender oil. First, warm up about one tablespoon of food-grade coconut oil… add a few drops of both tea tree oil and lavender oil. Stir and refrigerate until it solidifies, about an hour. Then you can apply a bit (use sparingly so it won’t get onto your clothing) of the mixture to your armpits just as you would with a commercial deodorant. “It feels good and you’ll smell great,” says Dr. Rubman. “And you won’t have to worry about blocking your apocrine glands.”  

Source(s):

 Kris G. McGrath, MD, associate professor of medicine, Northwestern University, Feinberg School of Medicine, Chicago.

 Andrew L. Rubman, ND, medical director, Southbury Clinic for Traditional Medicines, Southbury, Connecticut.