Like cadmium and copper, aluminum is classified as a metalloestrogen, a metal with estrogenic properties. And like cadmium and copper, aluminum appears to be a breast carcinogen. Aluminum has been shown to increase estrogen-related gene expression in breast cancer cells. Aluminum can damage DNA and compromise the functioning of tumor suppressor genes (including BRCA1 and BRCA2) in normal breast cells. Aluminum accumulation in breast tissue increases inflammation, which could also contribute to breast cancer risk.

Studies have demonstrated that the presence of aluminum increases the migratory capacity (ability to move freely and distance moved) of both hormone receptor positive (ER+/PR+) and triple negative (ER-/PR-/HER2-) breast cancer cells. The average level of aluminum in nipple aspirate fluids collected from breast cancer patients was found to be more than twice that of similar healthy women in one study. Now a new study has reported that the frequency and length of antiperspirant use helps determine the aluminum content of breast tissue. Antiperspirant use is also associated with increased breast cancer risk, especially among women who start frequent use of antiperspirants under age 30.

Sources of aluminum exposure

Most antiperspirant sprays, sticks, and roll-ons contain aluminum chlorohydrate or another aluminum salt to block the secretion of sweat. Aluminum in antiperspirants has been shown to enter into circulation through the skin. The amounts are generally tiny, with the highest exposures generated by spray antiperspirants, followed by sticks, then roll-ons.

Applying an antiperspirant to skin that is scraped, cut or irritated (such as may occur after shaving) can result in far higher exposures. The implication is that it is better to use roll-on or gel antiperspirants than sprays or solids. In addition, any such products should not be applied right after shaving or if the underarm skin is broken or shows signs of irritation. It also makes sense to use as little as necessary and not to apply antiperspirants more than once per day. Best would be to use one of the available antiperspirants or deodorants that do not contain aluminum.

Other common sources of aluminum exposure include antacids, baking powder, and the use of aluminum cookware, utensils, packaging and containers. Consumption of acidic foods or liquids significantly increases aluminum absorption.

Latest research finds antiperspirants increase breast aluminum content & BC risk

The age-matched case-control study referenced at the beginning of this news story was designed to investigate the association between self-reported use of underarm cosmetic products (which we will refer to as antiperspirants) and risk of breast cancer. The study included 209 women with breast cancer and 209 healthy women who acted as cancer-free controls. Data concerning the women 's use of antiperspirants over time was collected. Breast tissue aluminum content was also measured in 100 of the breast cancer cases and 52 of the controls.

Use of antiperspirants was found to be significantly associated with increased breast cancer risk. The risk was especially high for women who reported using antiperspirants more than once per day starting before age 30 (3.88 times higher than the risk for non-users). Aluminum was found in the breast tissue of both cases and controls, however it was higher in antiperspirant users and significantly associated with the level of self-reported use. The authors conclude that frequent use of antiperspirants might lead to accumulation of aluminum in breast tissue. In addition, more than daily use of antiperspirants at younger ages may increase the risk of breast cancer, according to the authors.

For more information, please see our aluminum tag and our article on protecting our daughters from breast cancer in the teenage years and young adulthood.