The aluminum in deodorants is often mentioned among substances to avoid in skin care products and switching to an aluminum-free deodorant is a common step when going green in your skin care routine. The reason is claims that aluminum cause breast cancer. There are, however, many scientists that disagree and consider it an urban myth. That there are no connections whatsoever between deodorant use and breast cancer. This was also the conclusion reached by the EC's Scientific Committee on Consumer Safety (SCCS) in 2014 when they found that none of the studies done so far on the subject deodorants and breast cancer were performed according to good laboratory practice and therefore impossible to draw conclusions from . So what is the truth? Are there any scientific proofs behind these claims? We have gone through the scientific reports in question as well as looked at the newer studies published after 2014. Even if we in many cases agree with the EC report, we find some of the new results that have emerged on the subject clearly distressing. Even if there are no clear proofs, on the basis of current data, it is hard to state that the aluminum in deodorants are completely harmless and it might be a good idea to play it safe and avoid aluminum deodorants.
Why These Suspicions About Underarm Cosmetics as a Cause of Breast Cancer?
The first sign that something is wrong when it comes to deodorants is that a majority of all breast cancer cases starts in the upper, outer quadrant of the breast. We are talking figures varying from 35-60% from report to report, while the other quadrants are responsible for about 5-15% of the cases. This is extremely disturbing figures and there are studies that try to explain this with that in the upper, outer region of the breast there is more tissue of the type that is involved in breast cancer . The problem with this explanation is that the number of breast cancer cases starting in the upper, outer quadrant has increased since the late 1970s . Maybe not linearly as the authors of the report try to argue but the numbers do show a clear rise between the 1970s and the 1990s, which then appears to stagnate until the present day. This among the cases reported in Scotland, England and Wales. Most marked is the increase among the youngest women, those diagnosed with breast cancer before the age of 50. A more recent study confirms the increase in England but fails to see as clear a trend in corresponding American data .
Rise in Breast Cancer Cases Worldwide
Breast cancer is more common in the West than the rest of the world and has doubled in the number of cases per 100,000 people since the 1970s and almost tripled since 1940s [4,5]. Known risk factors are genetic predisposition, estrogen treatments, alcohol consumption, BMI and age at the first pregnancy. About half of the cases cannot be linked to any known risk factor why there is a search for other lifestyle factors.
Epidemiological Studies With Contradictory Results
While deodorants only disguise bad odors, antiperspirants inhibit transpiration. Virtually all antiperspirants contain aluminum salts, most commonly aluminum chlorohydrate or aluminum chloride. The mechanism for how aluminum inhibits transpiration is not perfectly clear but the belief is that it forms a plug that blocks the sweet ducts. So far, four studies have tried to see a connection between the use of deodorants / antiperspirants and breast cancer [5-8]. The two earliest, one from the US and one from Iraq, simply looked at how many breast cancer patients used antiperspirants or deodorants compared to a control group. Both these studies failed to see any increased risk for breast cancer from use of underarm cosmetics [6,8]. Another study from 2003 focused instead on the usage pattern of antiperspirants, deodorants as well as underarm shaving in breast cancer patients and compared with the patients age at diagnosis . The patients were divided into four groups based on how often they used antiperspirants or deodorants where the Max-group corresponded to use 2-5 times/week combined with shaving at least 3 times/week. The study saw a gradual decrease of the age at diagnosis with increased use of antiperspirants. Between the Max-group and the Non-group, i.e. no antiperspirant, no shaving, the difference was astounding, all of 15 years differed between the group's average age when breast cancer was diagnosed. In addition, when they looked only at the Max-group, they could within the group see a difference of 19 years between those who started to use antiperspirants before the age of 16 and those who started later in life. A very recent study has looked more closely at the frequency of antiperspirant use and also measured the concentration of aluminum in breast tissue in breast cancer patients and compared with age matched controls. . This study saw a clear increased risk from use of antiperspirants several times a day before the age of 30. After compensation for other risk factors was the increased risk from use of antiperspirants almost 4 times. The amount of aluminum in breast tissue was significantly linked to the frequency of antiperspirant use. Measurement of aluminum showed significantly more aluminum in the breast tissue of the patients compared with the controls. Additionally could the scientist see a significantly increased amount of aluminum in the patients whose tumors were localized to the in the upper, outer quadrant compared to patients with tumors in other quadrants.
Uptake of Aluminum Through the Skin
Unlike other metals such as iron, copper, zinc, manganese and cobalt, aluminum is not a trace element and is not necessary for the body. On the other hand, aluminum is not a heavy metal either. Nonetheless, many studies indicate that aluminum is toxic for us and point to a link between aluminum and neurodegenerative diseases such as Alzheimer's [9,10].
The substances in an antiperspirant are not rinsed away in the same way as the content in shampoo and shower gel but stays on the skin until your next shower. Therefore it constitutes a continuous exposure. What's more, the habit to shave just before applying antiperspirants causes small nicks and abrasions, which increases the uptake of the substances in the antiperspirant.
There seems to be a common misconception that Aluminum chlorohydrate is too big a molecule to be taken up by the skin. However, aluminum chlorohydrate is highly soluble in water, in fact more soluble than table salt (50g versus 36g/100 ml at room temperature) meaning that it disperses into free ions in water. It has been shown that aluminum is taken up through the skin [11-13]. The uptake was higher in damaged skin shown by so-called tape stripping, a method where the outmost layers of cells are removed with the help of a tape . The same study also showed that the aluminum applied as an aerosol was more efficiently taken up than the aluminum in roll-on or stick deodorants.
Aluminum has been found in breast tissue  as well as breast milk . There are also some studies that indicate that the amount of aluminum is higher in cancerous breast tissue than in non-cancerous [16,17]. Aluminum concentrations many times higher than in blood sera has been measured in cystic fluid in patients with benign breast cysts . Unfortunately, no attempts were made to correlate this result with usage patterns of aluminum antiperspirants. Yet another study suggests increased amounts of aluminum in breast nipple fluid in breast cancer patients but the study was performed on a very small group of women (18 cancer patients and 16 controls), which makes it difficult to draw any strong conclusions .
One should, however, bear in mind that we also take up aluminum via the food and the presence of aluminum in breast tissue and breast milk not necessarily is a result of aluminum containing antiperspirants.
Aluminum and Estrogenic Effects
Dr. Philippa Darbre is one of the scientists who has almost relentlessly pursued the question of a link between aluminum and breast cancer and she has put up with a great deal of criticism from colleagues for her research. Dr. Darbre has with her research tried to show that aluminum chloride och aluminum chlorohydrate have a direct hormone disrupting effect on the estrogen receptor . The study is, however, badly substantiated and based on only three single experiments, which she does not repeat to exclude chance. The concentrations of aluminum used to show competition with estrogen for its receptor were sky high and completely unreasonable in the context. We are talking about amounts 2,5-10 million times higher than estrogen. The same goes for the attempt to show effects on growth of breast cancer cells. Estrogen normally has a growth stimulating effect on breast cancer cells but the high doses of aluminum used in the experiment only causes the cells to grow slower than normal. Finally, Dr. Darbre makes an attempt to show that aluminum can affect the estrogen effect, i.e. she uses a system where positive binding to the estrogen receptor (binding and activation) results in a measurable effect. In the study estrogen is compared with 10,000 times higher doses of aluminum. She then observes an increased effect with aluminum by its own and a strong effect of estrogen and aluminum together. The problem is the complete lack of controls. Normally this type of study should be verified in the absence of the receptor to rule out that the measured effect is not caused in some other way, i.e. is an artifact. Furthermore, if the estrogen effect was real, the treatment of breast cancer cells with aluminum should have caused a growth stimulation.
These results do not eliminate the possibility of aluminum having a causal effect on breast cancer, they only suggest it is not very likely to occur via the estrogen receptor.
Aluminum and Breast Cancer
Aluminum is not directly mutagenic. Attempts to show that aluminum can directly cause mutations have failed. . Regardless, presence of aluminum seems to result in increased DNA damage in the form of double strand breaks . A serious type of damage to DNA that is particularly difficult to repair correctly since both the strands are broken and there is no longer any template to follow. There is also a study that shows that aluminum seems to affect normal cells to display cells a more oncogenic behavior . Long-term treatment of breast cells with aluminum chlorohydrate and aluminum chloride resulted in a loss of contact inhibition and anchor-independent growth, two typical attributes for oncogenic cells. Yet another long-term study indicated that aluminum increased the migration of the cells and resulted in a tendency for invasive behavior, in other words, their propensity to spread and metastasize . These last experiments on cell migration and invasion were not repeated though and one should be careful not to draw to strong conclusions based on them.
A study from the US on a small group of breast cancer patients showed increased genetic instability in the outer region of the breast in non-carcinogenous tissue . No difference could be seen between the upper and lower region though. Genetic instability can, of course, be caused by various reasons but one possibility is impaired repair of DNA damage. A very recent study has found a connection between a protein extremely important for correct repair of DNA damage, namely BRCA1, whose gene is also called the breast cancer gene. BRCA1 is part of a complex that repairs DNA double strand breaks. Mutations that result in loss of function of BRCA1 protein increase the risk for developing breast cancer at some point in your life to 80%. The study in question found that treatment of cells with either aluminum chlorohydrate or aluminum chloride dramatically decreased the amount of BRCA1 proteins in the cells . However, the study is only done on cells in a laboratory and the results need to be verified on human tissue, preferably in correlation with aluminum deodorant use. But if the connection between aluminum and BRCA1 holds true, it is extremely serious and would definitely constitute a mechanism for how aluminum in deodorants can increase the risk for breast cancer.
Avoid Aluminum in Deodorants
Taken together, the recent scientific reports indicate that aluminum in deodorants is not completely harmless. Even if the outcome so far not inconclusively points to aluminum as a risk factor in breast cancer are the results distressing and clearly question the general opinion that aluminum is safe.This is particularly alarming considering the widespread use of aluminum deodorants in the West. So even if aluminum is not yet proven toxic it is better to take no chances and to completely avoid deodorants containing either aluminum chloride or aluminum chlorohydrate, at least until proven otherwise.
Crystal Deodorants – To Avoid or Not?
Potassium alum alternatively Ammonium alum (Chemically; Potassium aluminum sulfate; KAl(SO4)2 or Ammonium aluminum sulfate; NH4)Al(SO4)2) are common in many alternative, natural deodorants, sometimes marketed as aluminum-free, which, of course, is incorrect.
Alum is a naturally available salt possessing antibacterial, constringent and blood-stopping properties and has traditionally been used as a deodorant in various parts of the world. The big difference between deodorants containing alum compared with aluminum chloride or aluminum chlorohydrate is that alum has antibacterial but no antiperspirant properties or at least is a much weaker antiperspirant than the other two salts. Possibly this is due to a lesser uptake of alum compared with the other two salts but since the mechanism behind the antiperspirant effect aluminum salts is not completely understood it is difficult to say if this the case. Unfortunately none of the studies that have looked at uptake of aluminum chloride and aluminum chlorohydrate included alum in the tests and at present there are no physiological studies done on this salt. The solubility in water at room temperature is about 3.5 times less for alum in comparison to the other aluminum salts, which could entail that the uptake through the skin is lower but would hardly prevent it from being taken up at all. Considering that the increased risk for breast cancer development was only seen at excessive use of antiperspirants it may be a question of concentration. Until this is fully investigated we would like to urge for caution regarding crystal deodorants and natural deodorants containing potassium alum or ammonium alum, especially among those that already are at higher risk for other reasons, for example has a family history of breast cancer or are using estrogen supplements. In addition, teenagers, pregnant women and nursing mothers would also be wise to avoid crystal deodorants.
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