Debunking the Myths - Sodium Lauryl Sulfate

You may have seen this ominous email floating around in your inbox somewhere:

Source: snopes.com

But take the warning with a grain of salt, as not everything in this email may be true... First of all, there is an inherent error within the email chain. It states Sodium Laureth Sulfate, and abbreviates it to SLS, while SLS is actually Sodium Lauryl Sulfate, and the abbreviation for Sodium Laureth Sulfate is SLES. The difference between the two compounds is small, with just an additional ether group in SLES. SLES tends to be a little less irritating to the skin, but other than that, the compounds are pretty much the same.
But with that little bit of snarkiness aside, let's take a closer look at the compound in question:

Sodium Lauryl Sulfate

Structure of Sodium Lauryl Sulfate

SLS is an anionic synthetic detergent, which means that it is a long carbon chain to which a sulfate group (-SO4) is attached, forming the negatively charged (anionic) part. The 12-carbon tail attached to the sulfate group gives the material its amphiphilic properties, or both water loving and water hating. The carbon end of the compound is the nonpolar, hydrophobic side, while the sulfate side is the negatively charged, polar, hydrophilic part. Amphiphilicity is required of detergents, because it needs to be water hating, so it can attach to the oils and greases to be removes, and water loving, so it can be rinsed off easily with water. This property is what makes SLS so abundant in things like shampoos and soaps etc.
However, SLS still does pose some threats. SLS has been found to have many side effects, such as:

• Eye, skin and mouth irritations
• Membrane alterations
• Harmful to the brain, heart, spleen, liver
• Chronic irritant contact dermatitis
• Harmful to normal cell function
• Corrosive to hair follicle, and can cause hair loss

With a rap sheet like this, you might wonder why SLS is used in virtually all shampoos, toothpastes, mouth washes, and more. Well while the above may be true for SLS, the concentration of SLS in these common products is too low to make a difference. Also because our skin only comes in contact with the products for a short amount of time, it doesn't affect it in any noticeably way. As long as you don't marinate your scalp in it every night, SLS will not cause any harm. 

Even if all these harmful effects were possible of SLS, nowhere on that list is "carcinogen". So how did the myth of SLS being a carcinogen come to be?

Back in the 70s, due to sketchy manufacturing processes, small amounts of nitrosamines, which are carcinogens, entered into the shampoos. Somehow, the dubious rumor began that SLS reacted with formaldehyde to make nitrosamine. However, anyone with half a brain can figure out that since first of all, nitrogen is absent in both of those compounds, there is no way to put them together to make a nitrogen containing compounds

It would take some pretty strong, black magic to make this reaction happen

SLS + Formaldehyde --> R¹N(-R²)-N=O???

Therefore, the myth that SLS is a cancer causing compound found in shampoos is FALSE. While it is true that it can be a potential skin irritant, and have dangerous side effects, we are not exposed to it for a long enough time and at a high enough concentration for it to actually affect us. So by all means, continue lathering away with your safe shampoos and soaps!

jennymu

Antioxidants and Aging

In the cosmetic world, anti-aging creams are popping up with increasing frequency. They claim to make you look decades younger by removing wrinkles, spots, and giving you a youthful glow. Seems like a miracle to me. Such miracles don't come cheap either, with prices in the hundreds being average. Is a jar of this anti-aging cream worth it, or is it just empty promises in a nice little package? We'll take a closer look at one of the major contributors of aging, and how cosmetic companies combat it.

Oxidative stress is one of the leading causes of aging signs, so it makes sense that many cosmetic companies try to target this when developing anti-aging products. This post will give more insight into what oxidative stress is, and the method by which these companies try and reduce it.

Here is a helpful introductory video:

The human body needs a balance in redox reactions. "Redox" is a scientific term used to describe chemical reactions that involve the addition or reduction of electrons to molecules, thus altering oxidation numbers or "oxidation states". Reduction is adding electrons to an atom, and oxidation is removing electrons from an atom. The result of this change can be destructive (think rusting iron, a commonplace example of oxidation). Therefore, oxidative stress is basically an imbalance between the production of free radicals, the oxidizing agent, and antioxidants, which are reducing agents. When there are too many free radicals to be reduced by the antioxidants, this creates oxidative stress within the body.
Free radicals are electronically unstable atoms or molecules capable of stripping electrons from any other molecules that they meet in an effort to achieve stability. In their wake, they create even more unstable molecules that attack their neighbors in a domino-like chain reactions. This causes extensive damage to the cells.
Disturbances in this normal redox state in the body can cause toxic effects due to the production of free radicals that will inflict molecular damage to the proteins, DNA, lipids, and other biomolecules in your body, in a process called "oxidative stress". Oxidative stress basically is an imbalance between the production of free radicals, reactive oxygen species,  and antioxidants defense species. This way, the free radicals, the oxidation part, end up overwhelming the antioxidants, which are reducing agents, and so we see oxidation of important molecules such as proteins, lipids, etc.
This oxidative stress can lead to premature signs of aging, one of the biggest fears most women have.

Premature aging: a woman's biggest fear

It seems intuitive, therefore, that one of the best ways to fight these free radicals is to up the amount of antioxidants. These antioxidants are able to neutralize the free radicals, and prevent them from damaging the cells in your body. While many creams include antioxidants in their extensive list of ingredients, is topical application really the best way to go? A 2011 study investigated this very question. The study looked at antioxidant levels in the skin after using them both topically and systemically. 129 healthy women, aged between 21 and 72 years, were divided into seven groups and given topical creams, oral supplements, both, or a placebo. Ultimately, the oral supplement group had the best results, sometimes even beating out the group that had both topical and oral. The human skin is a difficult barrier to penetrate, in order to keep out all the germs that cause diseases, and sometimes this can work negatively when it comes to things like antioxidants. Therefore, the best way to go about getting your daily dose of antioxidants is orally, through food.

Foods rich in antioxidants

Sources: 
http://www.sciencedirect.com/science/article/pii/S0923181110000782
http://www.ccjm.org/content/73/12/1049.full.pdf
http://www.wiley.com/college/boyer/0470003790/reviews/redox/redox.htm
http://www.healthchecksystems.com/antioxid.htm

jennymu