Is Your Deodorant Bad For Your Health?

 

By Jesica Levingston Mac Leod, PhD

Body odors (BO) are part of our evolution, and the ability to smell has evolved with us, making people fall in love or run away from a smelly person. Sweat has an initial effect to cool our body down and avoid overheating. Sweat can also be trigger by stress, anxiety or other hormonal changes. Sweat by itself doesn’t smell, but the bacteria located near the glands, for example, the armpits, breakdown the sweat generating the “BO”. How do we deal with the stinky fact? We apply deodorants and/or antiperspirants. Deodorants have ingredients like triclosan, which make the skin more salty or acidic for the bacteria to grow in those areas. Therefore deodorants don’t stop you from sweating, but antiperspirants will do the trick, as they contain ingredients like aluminum and zirconium, which are taken up through the pores and they react with water and swell, forming a gel that blocks the sweat.

Last year, Mandriota and collaborators demonstrated that in a cancer mouse model, concentrations of aluminum in the amount of those measured in the human breast are able to transform cultured mammary epithelial cells, allowing them to form tumors and to metastasize. Moreover, aluminum salts have been linked with DNA damage, oxidative stress, and estrogen action. In 2004, a woman reported aluminum poisoning after using antiperspirants for four years, and after stopping the use of these products the aluminum levels dropped and she recovered.

Breast cancer develops after cells with mutations in their DNA start growing uncontrolled, generating a tumor. Most breast cancers develop in the upper outer quadrant of the breast, near to the lymph nodes that are exposed to antiperspirants. This fact was the starting point for the theories that the underarm cosmetic products could be carcinogenic. One of the first publications on this subject dates from 2002; it was population-based (ages 20-74, 1606 patients) and found no correlation between breast cancer and antiperspirant use. A second article found a relationship between an earlier age of breast cancer diagnosis to more frequent regular use of antiperspirants/deodorants and underarm shaving.

Aluminum salts have been linked to increased risk of developing breast cancer, but so far the research on this has been quite inconsistent. Last month, a new research study of 418 women (ages 20 to 85) examined their self-reported history of use of underarm cosmetic products and health status, in order to unveil a bit more about the link between antiperspirants and breast cancer. Linhart and col. from Austria, studied the relationship of the use of underarm cosmetic products and the risk of breast cancer. They divided the group in two: half of the women were breast cancer patients and the other half healthy controls. Then, they measured the concentration of aluminum in the breast tissue of some of the women. The results showed that the risk of breast cancer increased by an odd ratio of 3.88 in females who described using the underarm products multiple times per day starting before their 30th birthday. Importantly: “aluminum traces were found in the breast tissue in both cancer patients and healthy controls and it was significantly associated to self-reported underarm cosmetic products use”. In fact, the median concentrations of aluminum were 5.8 (2.3-12.9) nmol/g in the tissues from breast cancer patients versus 3.8 (2.5-5.8) nmol/g in controls. The conclusion is that more than daily use of these cosmetic products at younger ages may lead to the accumulation of aluminum in breast tissue and increase the risk of breast cancer.

Although the American Cancer Society claims that “there are no strong epidemiologic studies in the medical literature that link breast cancer risk and antiperspirant use”, after the Linhart investigation, and knowing that 1 in 8 women will be diagnosed with breast cancer in her lifetime, I will avoid antiperspirants with aluminum. Nobody wants to be called “stinky”, so some actions to take are to wash your clothes after working out, take showers regularly and/or clean your armpits with water and soap as soon as you “smell something”, apply deodorant, and consult with your doctor about the best way to keep your body odors under control. The last resource: perfume. If you can’t win the fight… hide.

The Science of Solar Eclipses

By JoEllen McBride, PhD 

As the sky darkens on August 21st, we will stand in awe of the first total solar eclipse to cross over the contiguous U.S. in almost 40 years. This is also a chance for scientists to do what they do best– science!

 

Total Eclipse of the Sun

Every month, the Moon passes between the Earth and Sun during its New Moon phase. We can’t see the New Moon because the side that faces us isn’t illuminated by the Sun but it’s up there. Solar eclipses happen only when the Moon is in the New Moon phase and crosses the plane created by the Earth-Sun orbit. All other New Moons are either too high or too low in the orbit, to cover Sun.

 

A total solar eclipse is even more special. The cosmos has gifted us with a spectacular coincidence. The distance between the Moon and Earth is 400 times less than the distance between the Sun and Earth. This wouldn’t be interesting except for the fact the Moon is also 400 times smaller than the Sun. Once the Moon hits that sweet spot in its orbit around Earth, it completely covers the Sun.

 

That also means that sometimes a solar eclipse occurs and the Moon doesn’t completely cover the Sun. These are partial or annular eclipses and it just means that the Moon was too far from Earth to hide the Sun completely.

 

A solar eclipse occurs approximately every year and a half (give or take a few months). What makes them seem so rare is our planet is mostly ocean, so the chances of the solar eclipse passing over land with people on it is reduced. That’s why Monday’s total solar eclipse passing over the entire mainland U.S. is such a big deal! Don’t let Neil deGrasse Tyson put a damper on it!

 

Predicting Eclipses

It is true that for centuries solar eclipses were thought of as omens and bringers of terrible things by many human societies. But once we figured out that they were predictable, we quickly used them to learn about the universe. The first predicted eclipse was done by Thales of ancient Greece around 610 or 585 BCE. Thales made the prediction using the idea of deductive geometry borrowed from the Egyptians. Euclid, much later, formalized this into what is now known as Euclidean Geometry. The historical record shows that Thales’s prediction only worked one time though because there are no other accounts of anyone successfully predicting an eclipse until Ptolemy used Euclidean geometry in 150 CE.

 

So how can scientists use this periodic alignment of celestial bodies to their advantage? The Sun is a pretty reliable part of our day, so having it gone for a few moments allows us to study the reaction of animals to an abrupt change in their environment. You’ll hear birds stop singing and frogs and crickets will begin chirping as the sky darkens. Mammals will begin their bedtime rituals also. But we can learn the most about the Sun itself from a solar eclipse.

 

Image of the corona created by placing a disc over the Sun to mimic a solar eclipse. These instruments, called coronagraphs, still allow a little sunlight to get through which can mess up measurements of the corona. So scientists still rely on real deal total solar eclipses to study the corona in detail.
Image of the corona created by placing a disc over the Sun to mimic a solar eclipse. These instruments, called coronagraphs, still allow a little sunlight to get through which can mess up measurements of the corona. So scientists still rely on real deal total solar eclipses to study the corona in detail.

Grab a Corona

The Sun has an outer atmosphere extending millions of miles above its surface called the corona. At temperatures reaching a few million degrees Fahrenheit, the corona significantly hotter than the Sun’s surface. The corona was first observed in 968 CE during a solar eclipse and for many centuries, scientists debated whether this bright wispy envelope was part of the Sun or the Moon. It wasn’t recognized as being part of the Sun until the eclipse in 1724 and then verified over a century later in 1842. Then, during 1932 and 1940 solar eclipses, scientists determined that the corona is significantly hotter than the surface of the Sun. Iron atoms in the corona are stripped of their electrons, which can only happen if the atoms are heated to millions of degrees. This discovery still summons solar physicists to all parts of the planet to observe solar eclipses. This solar eclipse is no different. They’re still not sure why the corona is so hot.

 

Get You Some Flare

Solar eclipses also allow scientists to study another extremity of the Sun, solar flares. Solar flares or prominences are as spectacular as they are dangerous– especially today. They can disrupt satellites and other communications devices as well as short out electrical grids. So it is crucial that we understand as much as we can about them. The first solar prominence was observed, with the naked eye, during a partial solar eclipse in 334 CE. Knowing this probably would have helped Birger Wassenius during the total solar eclipse in 1733. He noticed solar flares but suspected they were coming from the Moon. It wasn’t until a solar eclipse in 1842 that scientists verified the ejections were coming from the Sun.

 

The Sun goes through cycles of solar flare activity about every 11 years. This year, the Sun is approaching a low point in its activity, so scientists will use this total eclipse to study how flares differ from when the Sun is more active.

 

Other Notable Discoveries Thanks to Solar Eclipses

In 1868 the element Helium was discovered in the Sun’s light during the 1868 and 1869 solar eclipses and named after the Sun (Helios = Sun in Greek). Helium wasn’t identified on Earth until 1895. Another big win for physics came during the 1919 solar eclipse. Scientists used the darkened sky to verify that the Sun is massive enough to bend the light of faraway stars before it reaches us. Stars that should have been behind the Sun– and therefore not visible during the eclipse– were clearly seen. This proved part of Einstein’s theory of relativity that massive objects bend space around them.

 

Solar eclipses are awe inspiring and also useful to science. So make sure you grab your eclipse glasses or pinhole cameras or fists and get out there!

 

What A Marshmallow Can Say About Your Brain

By Deirdre Sackett

In the 1970s, researchers at Stanford University performed a simple experiment. They offered children the chance to eat a single marshmallow right now, or wait 15 minutes to receive two marshmallows. Out of 600 children in the study, only about ⅓ were able to wait long enough for two treats. Most attempted to wait, but couldn’t make it through the whole 15 minutes. A minority of kids ate the marshmallow immediately.

 

Feeding marshmallows to children in the name of science may seem like a waste of federal funds. But it turns out that the ability to wait for a treat can actually predict a lot about someone’s personality and life trajectory.

 

Since the 70s, many scientific groups have repeated the “marshmallow test” (some of which have been hilariously documented). In some iterations, researchers recorded whether each child chose an immediate versus delayed treat, and then tracked the children’s characteristics as they grew up. Amazingly, the children’s choices predicted some important attributes later on in life. Generally, the more patient children who waited for the bigger reward would go on to score higher on the SAT, have a lower body mass index (BMI), and were more socially and cognitively competent compared to the kids who couldn’t wait and immediately ate one treat.

 

The “marshmallow test” measures a cognitive ability called delay discounting. The concept is that a big reward becomes less attractive (or “discounted”) the longer you need to wait for it. As such, delay discounting is a measure of impulsivity – how long are you willing to wait for something really good, before choosing a quicker, but less ideal, option?

 

While it’s okay to occasionally have spur-of-the-moment choices, poor delay discounting (increased impulsivity) is often a symptom of problematic gambling, ADHD, bipolar disorder, and other mental health issues. In particular, drug addiction is also accompanied by increased impulsive choices. For instance, drug users will choose immediate rewards (such as drugs of abuse) over delayed, long-term rewards (i.e., family life, socializing, or jobs). Drug users are poor at delay discounting and choose immediate options faster than non-drug users. This isn’t just a human flaw; exposing rats to cocaine also increases their impulsivity during delay discounting tasks.

 

Interestingly, aspects of the “marshmallow test” hint at this impulsivity-drug addiction link. In 2011, researchers did a follow-up study with the (now adult) children from the original 1970’s Stanford experiment. The scientists imaged the subjects’ brains while making them do a delayed gratification task in which they had to wait for a reward. They found that patient versus impulsive individuals had very different activity in two specific brain regions involved in drug addiction.

 

Firstly, the study found that impulsive individuals had greater activity in the ventral striatum, a brain region heavily linked to drug addiction and impulsivity. The greater activity in this region may imply that impulsive individuals process information about rewards differently than patient individuals. That is, the way their brain is wired may cause them to want their rewards right now.

 

Secondly, the impulsive individuals had less activity in the prefrontal cortex, which is responsible for “putting on the brakes” for impulsive actions. This finding suggests that impulsive individuals may not have that neural “supervisor” that can stop themselves from acting on their impulses. Drug addicts show similarly reduced prefrontal activity. So in addition to doing worse on standardized tests, having higher BMIs, or being less socially competent, the marshmallow test predicts that impulsive individuals may have brain activity similar to those of drug users.

 

While it seems like a silly experiment, the marshmallow test is a great starting point to help increase our understanding of impulsivity. Using this information, researchers can start to develop treatments for impulsive behavior that negatively affects people’s lives. Specifically, treating impulsivity in drug addicts could help as part of the rehabilitation process. So think about that the next time you reach for that sweet treat!