Monday, September 15, 2014

Sweating Is The Pits

It was in the late 9th century when some societies decided that armpits needed to be kept from fulfilling their stinky destinies. Some locales still haven't gotten the message. Deodorants and antiperspirants are meant to reduce the causes of axillary odor, axilla being the scientific term for armpit, but could we be doing more harm than good with them? Let’s find out.

What does this image have to do with armpits and deodorants?
Well, this is Ziryab, the inventor of the first known underarm
deodorant. He also made fashionable the idea of Muslim men
shaving their faces – still a matter of personal choice except in
some of the strictest sects. Ziryab was a scientist and an artist,
a polymath of the first degree – and maybe he developed the
first Degree (an antiperspirant – get it?).
A long time ago in the Islamic portion of Spain, a very smart guy name Ziryab invented what would later become the beauty aisles at CVS. He developed a deodorant for the axilla, a toothpaste for oral hygiene, bath salts for the skin, and oils and conditioners for the hair. This is only a little weird since he was really a musician and poet – although he had knowledge in astronomy meteorology and botany as well. Unfortunately, his inventions were lost and had to be reinvented later.

Mum was the first commercial deodorant marketed to reduce body odor from the armpits – it’s still around today under the name Ban. It was developed in Philadelphia in the late 1890’s, and became a commercial hit. Deodorants usually contain alcohol, acids, or triclosan, all of which kill or deter bacterial growth. More on that in a second.

Most deodorants also contain a masking fragrance, some perfume contained in a starch microsphere. When sweat breaks down the starch, it releases the fragrance. Starch spheres of different sizes means they breakdown after different periods of time in sweat, so they can keep you socially acceptable for longer periods of time.

On the antiperspirant side of the equation, Stopette was developed in 1941. Antiperspirants contain one or more of several aluminum compounds. Weird as it sounds, they work by combining with the ions in your sweat to clog up your pores so that you don’t sweat. Does that mean that prolonged use will force your underarms to swell from retained sweat until you explode and blow off both your arms. No- but it stirs up an interesting visual.

The function of deodorants/antiperspirants is to prevent you from offending everyone else due to the bacterial byproducts that buildup in your armpits as the day progresses. Bacteria are on your skin – all of your skin. In fact, you have more bacteria on your skin than you have skin cells. Like I said, a lot of bacteria.

Leonard Hofstader on The Big Bang Theory apparently
was stressing over his upcoming date with Penny. The
apocrine glands produce nutrient rich sweat with an
increase in stress hormones. They empty into the hair
follicles, as opposed to onto the skin directly for eccrine
glands. This is why some people shave their armpits to
reduce smell, the fatty products of apocrine glands stick
to hairs and promote more odor.
Your armpits (axilla in scientific terms) offer a warm, moist, food-filled cave in which bacteria thrive. You sweat to control temperature, and this sweat pours forth from the eccrine glands. There are also apocrine sweat glands that control emotional sweating, like when you’re stressed about that first date and all you have clean are royal blue dress shirts. 

Apocrine glands release water and salts like eccrine glands, but their sweat contains more fats, sugars and proteins – and this is food for bacteria. When you reach puberty, the number of these glands in the axilla increase greatly, up to 25,000-50,000 per pit. Apparently evolution has determined that kids don’t have anything to be stressed about.

Bacteria + bacterial food from sweat = bacterial growth and division. With more bacteria come more bacterial products. Basically, these products are chemicals that are produced as a function of bacterial metabolism – it’s their waste products, communication chemicals, and toxins that we smell later in the day.

This brings up an interesting point – well, interesting to me – deodorants suppress odor by killing bacteria and antiperspirants suppress bacterial growth by limiting their sweat-based food, and that then prevents the odor. So all antiperspirants are deodorants, but not all deodorants are antiperspirants. So that makes the products labeled as deodorant and antiperspirant just plain old redundant.

Actinobacteria produce some of the most foul smelling chemicals
associated with body odor. However, a subset of actinobacteria
called actinomycetes make a chemical called geosmin. This is
the chemical that gives the wonderful earthy smell after a rain.
We have discussed how deodorants/ antiperspirants help us, but new research is showing that they may have some drawbacks. A 2014 study in Belgium asked people to forgo their underarm cosmetic regimen for one month. The scientists found that there was a stable community of bacteria (number and types of bacteria = community) when using the products and a stable community when not using the products. But the bacterial communities were different in each situation, with more different types of bacteria seen in the unnatural condition.

In fact, more Actinobacteria were present when antiperspirants were being used, and these produce some of the foulest smelling by products. Therefore, we may be adding to our funk by trying to prevent it. Of course, everyone is entitled to their own crop of axillary bacteria, so differences were seen from individual to individual.

This is may be an unfortunate effect of antiperspirant usage, but there may be more important problems. All women are told not to wear deodorant or lotions when having a mammogram - but do you know why? We said that antiperspirants contain aluminum or zirconium, and we now know that these can stop X-rays from passing through tissue. They can look like small calcifications in the tissue of the breast, and this can lead to false readings of mammograms. That's bad enough, but they may contribute to breast cancer as well.

This is a mammogram image from a breast with cancer. The
main tumor is shown with a single arrow, and the associated
microcalcifications are shown with the double arrows.
Unfortunately, aluminum in antiperspirants can look just like
the calcifications, without or without underlying disease.
The evidence is far from conclusive, but certain studies have shown that the aluminum in antiperspirants can build up in the breast tissue over time. Other studies show that aluminum can stimulate estrogen-like hormone production, and estrogens are known to promote breast cancer cell growth. No studies have shown that antiperspirants cause breast cancer, but more study is needed.

A 2013 review discusses the various studies that indicate an effect of aluminum on breast physiology, including altered iron metabolism, increased oxygen radicals and increases in inflammation. On the other hand, another 2013 study found no difference in aluminum concentrations in normal and cancerous breast tissue, so the causative effect is definitely not proven.

On the other hand, antiperspirants don’t seem to interfere with radiation therapy for breast cancer. A 2012 paper indicated that aluminum based antiperspirants don’t affect the beams of radiation (much like X-rays) that are used to treat some early stage breast cancers. Antiperspirants might promote breast tumors, they do mimic how breast tumors look on X-rays, but apparently they don’t hurt the treatment once you already have breast tumors. Weird.

contributed by
Mark E. Lasbury, MS, MSEd, PhD
As Many Exceptions As Rules

Callewaert C, Hutapea P, Van de Wiele T, & Boon N (2014). Deodorants and antiperspirants affect the axillary bacterial community. Archives of dermatological research PMID: 25077920

Watson LC, Gies D, Thompson E, & Thomas B (2012). Randomized control trial: evaluating aluminum-based antiperspirant use, axilla skin toxicity, and reported quality of life in women receiving external beam radiotherapy for treatment of Stage 0, I, and II breast cancer. International journal of radiation oncology, biology, physics, 83 (1) PMID: 22516385

Darbre PD, Mannello F, & Exley C (2013). Aluminium and breast cancer: Sources of exposure, tissue measurements and mechanisms of toxicological actions on breast biology. Journal of inorganic biochemistry, 128, 257-61 PMID: 23899626

Rodrigues-Peres RM, Cadore S, Febraio S, Heinrich JK, Serra KP, Derchain SF, Vassallo J, & Sarian LO (2013). Aluminum concentrations in central and peripheral areas of malignant breast lesions do not differ from those in normal breast tissues. BMC cancer, 13 PMID: 23496847

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