Deodorants and cancer
You may have heard rumours that deodorants and antiperspirants could cause breast cancer. But these concerns were started by an e-mail hoax. There is no convincing evidence that antiperspirants and deodorants cause breast cancer.
An email hoax
The original e-mail claimed that antiperspirants stop your body from sweating out poisons. It suggested that these toxins build up in the lymph glands under the arm and cause breast cancer.
But the details of this are wrong. Breast cancers start in the breast and only later spread to lymph glands. Your body also has several ways of getting rid of toxins, and while sweating is one of them, it is a different system to the lymph glands.
Parabens and breast tumours
A small study found traces of parabens, a chemical found in some deodorants, in some breast tumours. Parabens are similar to oestrogen, the human hormone that can increase the risk of breast cancer at high levels.
But parabens are much weaker than oestrogen itself and any effects it has are likely to be overwhelmed by natural oestrogen produced in our body, or similar chemicals found in our diet.
Finding parabens in tumours is a far cry from saying that it causes breast cancer. To do that, scientists would need to compare levels in breast tumours to "safe" thresholds, to levels in healthy body cells, or to levels in healthy people without cancer. These studies have not been done.
In fact, breast tumours have large blood supplies and are likely to contain traces of anything that finds its way into our bloodstream. The study didn't show that these parabens came from using deodorants rather than intake from food or any other source. And besides, most modern deodorants are parabens-free.
Aluminium in deodorants
There is no evidence that aluminium in deodorants could increase the risk of cancer in animals or humans. This was confirmed by a review of all the available evidence in 2014 that found no link.
A small study in 17 women with breast cancer was quite widely reported in the news in 2007. It found higher levels of aluminium in the part of the breast nearest the skin, and the authors speculated that aluminium in deodorants might cause breast cancer.
But the design of this study was not strong enough to draw that conclusion. For a start, it looked at a very small number of women. And the researchers did not compare levels of aluminium in these womens' breasts to levels in other parts of their bodies, or to levels in women who do not have breast cancer.
Furthermore, a larger study of 176 women in 2013 showed no significant differences in levels of aluminium in normal areas of the breast to the level in the tumour.
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