The Science Behind Why You Love or Hate Scary Movies

In anticipation of Halloween, October is a month full of spooky festivities including scary movies. Gathering a group of friends to watch a horror movie is a fun holiday activity, but finding a movie that appeals to a broad range of people can be challenging.  After I watched The Taking of Deborah Logan with some friends, we were evenly split on the number of people who found the movie enjoyable or traumatizing. This made me wonder: why do some people love to be scared, while others hate it?

https://www.flickr.com/photos/juanedc/8076488397

Carefully edited movies can elicit similar patterns of brain activity among viewers.

Fortunately, scientists have investigated how watching movies affects our brains. There is even a name for this branch of studies: neurocinema. In these studies, viewers watch movies while being monitored by functional magnetic resonance imaging (fMRI). Unlike traditional MRI, which generates anatomical images, fMRI measures activity by detecting changes in blood flow. Scientists can use fMRI to study brain activity changes in response to watching a movie because blood flow increases when neurons are activated. In a study by Hasson et al. the authors demonstrated that, compared to unstructured recordings, carefully edited movies can elicit similar patterns of brain activity and eye movement among a variety of viewers. However, horror movies are often carefully planned to shock and terrify so there must be more to people’s preferences than brain activity patterns.

There are multiple theories about why some people enjoy being scared more than others. Some theories suggest the individual differences may be attributed to brain chemistry. For example, fear-seekers may be more sensitive to the rewarding effects of dopamine, a neurotransmitter involved in the flight-or-fight response. A similar, sensation-seeking theory suggests that scary movie enthusiasts enjoy the feelings of heightened stimulation.

https://www.flickr.com/photos/130455326@N05/24038448170

Scary movie scenes, common in Halloween movies, can help sensation-seekers compensate for hypoactivation during lower intensity stimulation.

To test the sensation-seeking theory, in a study performed by Straube et al., people answered a questionnaire to determine their level of sensation-seeking and then watched scary and neutral scenes from horror movies while being monitored by fMRI. Interestingly, sensation-seekers, or people with high sensation-seeking scores, had lower brain activation while watching neutral scenes. However, sensation seekers had higher brain activity while watching scary scenes than non-sensation seekers. This suggests that sensation-seekers might experience hypoactivation during lower intensity stimulation, such as neutral movie scenes and compensate by seeking more intense stimulation with scary scenes.

So, if you find yourself cringing in horror at the movie selections this Halloween, blame your brain. The good news is there are plenty of light-hearted Halloween options. I personally recommend Young Frankenstein.

Peer edited by Breanna Turman.

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Like It or Not, Your Internet Trail is Inevitable

I love online shopping. On the Internet I can ponder over one pair of shoes a thousand times without any store clerk getting impatient. For that my mom isn’t quite comfortable with. She warns me about hackers stealing my identity from giving out my name, phone number, or home address. I always laugh at her paranoid personality and then brush it off. But honestly – she’s more correct than I’d like to admit.

Nowadays every step we take online is carefully monitored, traced and stored. All of this data is highly valued for advertisers to target potential customers, turning us into products. While separate parts of this data – gender, age, your likes and status updates, connections and club members – are worthless, once they are assembled and interpreted, the marketers can successfully paint a precise picture of you. With more than 2 billion monthly active users, a third of the world’s population, Facebook actively collaborates with affiliate data broker to create more efficient advertising channels. Last year, the Washington Post published on different 98 targeting options Facebook pulls from other companies to pinpoint the users’ identity. These numerous digital predictions which we give away on daily basis can not only be used to sell things, but even more importantly, to potentially sell a candidate. In case you’re wondering how to stop them from targeting you and to escape from the so-called “useful and relevant” advertisements, see what Facebook knows about you. Twitter is watching as well. Here’s to shut off Amazon figuring you out. Google, too, is built on serving advertisements.

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What does the Internet know about you? All the information you consume online is tracked cross sites.

The Chrome extension Data Selfie is created to dive deeper into how your Facebook activity is measured and interpreted. Based on the contents you looked at, clicked (through likes and links) and the time engagement in posts, the app categorizes you into personality profile groups using the machine learning algorithm Apply Magic Sauce developed by University of Cambridge. In terms of my Big 5 personality traits, I’m more conservative and competitive, and I’m more easily stressed than relaxed. It also classifies my Jungian personality type to ISTPs, Introverted Sensing Thinking Perceiving, who are suited to the field of engineering. It’s likely anyone who knows me would agree, to some extent. Given that these tools only scratch the surface of social network’s data curation, it’s disquieting to comprehend just how much information they have.

Even if you don’t have a social media profile, it doesn’t mean you are not out there. Simply log onto the Internet, you start leaving a larger digital footprint more than you think. Simulating what a website picks up, often times without ostensible consent, Webcay displays a cascade of data reported by your browser. Concerning the sensitive information browsers can monitor, Cooper Quintin, a security researcher for the Electronic Frontier Foundation told to The New York Times, “More than just being creepy, it’s a huge violation of privacy.”

We are being watched more than ever before, thanks to the relentless development of digital technology. While it’s possible to opt-out personalized advertising, changing data settings won’t remove you from advertisers’ audiences, as Twitter qualified. And even if you can trail data through apps and tools, you can’t reclaim all of your information because that’s something you agree to when you sign up for the services. What you can do is always be Internet aware as you fill out your personal details, interact with your News Feed, and browse the web.

Peer edited by Gabrielle Budziszewski.

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Burn Baby Burn! For the Longleaf Pines

The recent forest fires have been wreaking havoc across California since early October. In fact, destructive wildfires are a frequent occurrence in the dry, western state. Such fires are generally bad news as they cause destruction of property and affect air quality. However, are they always bad? Interestingly, the answer is no.

Wildfires can be an intricate part of a forest’s natural cycle, and may even help its survival. One such example lies in front of our eyes in the state of North Carolina, where the longleaf pine finds its home.

Longleaf pine forests across the Southeastern United States are one of the most diverse environmental systems in North America. At one point in time, they covered about ninety million acres of land which, unfortunately, has decreased to only about three million acres. Human development and exclusion of fires by human effort are largely responsible for this decline. Longleaf pines are adapted to fire cycles; preventing fires actually hurts the health of the forest. Native Americans realized this correlation and rarely intervened whenever lightning induced fires, which were common events in the Sandhills region, a major home of the longleaf pines located in North Carolina, South Carolina, and Georgia.When the early European settlers came over, they realized the potential of pine resin in shipbuilding. Very soon, North Carolina’s pine forests became a supply line of naval stores for the UK’s Royal Navy. These early settlers however still continued to burn fires like the natives and thereby contributed to the health of the ecosystem. It was only with growth in plantation forestry came an urge to desperately eliminate fires.

Photo taken by Manisit Das

Longleaf pines, in their sparkling green glory. Weymouth Woods, Southern Pines, NC

The Sandhills region is home to about a thousand different plant species, the dominant species being the longleaf pines. With their long needles, the pines produce a bright, shiny green canopy growing atop massively tall trunks.Additionally, the forests support a wide variety of animals amounting to 160 different species of birds, including the endangered red-cockaded woodpeckers, a large number of salamanders, toads, frogs, the hognose snakes, and fox squirrels, and many other species.  In the twentieth century, firefighting prevented the regeneration of longleaf pines, providing non-fire resistant species a competitive edge. That, coupled with increasing human settlement, reduced longleaf pine forest covers. In 1963, the remnants of the natural home of the longleaf pines were brought under the state parks system when Weymouth Woods was established. Since then, simulated prescribed fires are used systematically as a conservation tool to restore and maintain the longleaf pines.

An unexpected player in the conservation effort is the US military. The military base Fort Bragg, bordering the towns of Fayetteville and Southern Pines in North Carolina, is home to some of the world’s largest biodiversity reserves. The army recognizes that maintenance of the natural environment is crucial. The live ammunition exercises conducted by the military in this base already help protect many of the plant species, some of which are exclusive to Fort Bragg. If these rare plants are not preserved, most of the world’s populations of these species will be lost. Understanding the need of the hour, the military installation is taking one further step: in collaboration with the North Carolina Botanical Garden, they have launched an effort to reintroduce some of the plant species at risk into the Sandhills ecosystem.

Weymouth Woods Sandhills Nature Preserve, a North Carolina State Park in the Moore County around Fort Bragg, offers a great snapshot of the magnificent pine forests that once covered the southeastern United States. During my visit, I was surprised by the wide variety of wildlife I encountered within a short period along the sandy trails. This included a large number of dragonflies, skinks, a moccasin, and not to mention the diversity of plants that coexist in the Sandhills pine forests. If you are intrigued by the unique nature and ecology of the longleaf pines, their role in North Carolina’s history, or simply take pride in being a ‘Tar Heel’, I definitely recommend visiting this place. You will not be disappointed in this treasure trove of nature.

Peer edited by Caitlyn Molloy.

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Nanotechnology in Your Sunscreen: Doing More Harm than Good?

While soaking in the sunshine may feel good, and you may have heard about solar ultraviolet (UV) radiation harm, you may not be aware of what’s in your sunscreen. Lee Hong explored the benefits of sunscreen in his post on The Pipettepen, and today, we dive deeper into a smaller world – the nanotechnology in our sunscreen.

The two minerals available to sunscreen in form of nanosized particles (NPs) are zinc oxide (ZnO) and titanium dioxide (TiO2). They are less than 1/1000th the size of a human hair. Bulkier minerals in traditional sunscreen reflect visible light, making it opaque and cakey on your skin. NPs on the other side, scatter light instead of reflecting it, resulting in a disappearing and lighter feeling sunscreen.

https://www.flickr.com/photos/77654185@N07/14549162578/

Traditional sunscreens block out UV rays but many with ghostly white color. Nanotechnology make them disappear on your face!

While the resulting nanoproduct can be a big help, people have raised concerns over the safety of NPs-based cosmetic sunscreens. With their smaller size, NPs could in theory be absorbed into the skin at a higher level than their bulkier counterparts. The real question to ask is if these tiny particles are more harmful if absorbed, than good in protecting us from UV rays.

Studies are divided about whether NPs can pass through the skin. A few reassuring words from Paul Wright, a toxicology researcher at RMIT University, “There’s a negligible penetration of sunscreen particles,” as he told The Guardian, “They don’t get past the outermost dead layer of human skin cells.” In 2017, the Australian Therapeutic Goods Administration (TGA) published its review that NPs absorption is unlikely, based on both via in-vitro (i.e. studies using isolated skin cells) and in-vivo (i.e. studies on live skin tissue) studies. It appears that we are in a safe zone!

Other scientists have tested on the toxicity of these tiny metal oxides when exposed to UV light, simulating the real-life scenario for use of sunscreens. Their results indicated that the metal oxides may generate reactive free-radical species, leading to cancer due to DNA damage. However, this alarming impact on human health depends on whether NPs in sunscreen are absorbed into our skin. Providing some comfort, research associate Simon James at the Australian Synchrotron told to The Guardian that “Our study demonstrates that the human immune system has the right equipment to remove any nanoparticles that somehow make it through the skin, assuming some do at all.” Their work showed that human natural defenses can gather and destroy ZnO nanoparticles. Moreover, sunscreen manufacturers utilize surface coatings to improve transparent effect and as a result, the coated components can essentially reduce toxicity from lessen reactivity to UV lights.

https://www.flickr.com/photos/jimnix/7867453946/

It’s not a bad idea shielding your skin from burning sun with an umbrella’s shade whenever you are up for outdoor activities.

With the increased popularity of the nanotech-based products, another concern is noxious effects caused by inhalation of NPs. The Environmental Working Group (EWG), based out of Washington, D. C., announced a warning to refrain from spray sunscreen and loose powder cosmetics containing ZnO or TiO2 particles. The lungs have difficulty removing small particles and thus end up with organ damage possibly in the same way that air pollution is linked to lung cancer.

Evidence suggests there is more harm from skipping the sunscreen than exposing your skin to nanoparticles, but, if you’re not comfortable with these tiny oxides, UV protection umbrellas are another option!

Peer edited by Bailey DeBarmore.

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Spice is Nice (for Birds)

My labmate was having a problem one morning – a fuzzy, gluttonous problem. To help keep her indoor cat entertained during her time at work, she thought it was a great idea to set up a bird feeder. Being so close to the woods, surely this would bring all of the birds to the yard. Unfortunately, the local squirrels soon flocked to the free food source like a group of grad students and left not one seed for their colorful avian counterparts. My advice to her? Grab the hot sauce!

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Capsaicin is the compound in peppers that makes them hot and spicy

Making the bird feeder a literal hot spot by sprinkling high-Scoville sauces on seeds is not meant to suggest that birds engage in the same machismo food challenges as humans. They simply are not irritated by the chemical in peppers that is “hot” to humans and other mammals: capsaicin.

 

There are biological differences between certain pain perception receptors in birds and mammals. The TRPV1 (transient receptor potential vanilloid subfamily, member 1) receptor, also known as the capsaicin receptor, is involved in the perception of unpleasant or harmful chemical, physical, and thermal stimuli. The molecular sequence of this receptor between birds and mammals is only 68% similar, as compared to the >95% similarity for most other central nervous system receptors. What this translates to is an unusually high avian threshold for tolerating the spice in hot peppers. While mammals are put off by concentrations of 10-100 ppm (up to about the heat level of a jalapeño pepper), birds are not even fazed by capsaicin levels >20,000 ppm (habanero pepper territory).

Picture by Lindsay Walton

Birds are insensitive to the burn of capsaicin from hot peppers, making spicy bird food less appealing to squirrels.

Chili peppers take advantage of this natural disparity in receptor sensitivity, according to the directed deterrence hypothesis, which states that fruits produce noxious or toxic chemicals that make them more appealing to organisms that will disperse their seeds and less appealing to those that would destroy the seeds. This is especially handy because the regions in which hot peppers grow (for example, throughout Central and South America) are favorable places for seed-eating rodents to thrive. It is common knowledge to chefs and laymen alike that the seeds of chili peppers are much hotter than the surrounding fruit, which serves as extra insurance against seed destruction by mammals that may be more desensitized to capsaicin than the average bear, so to speak.

 

While sprinkling hot sauce on your bird feed or suet cakes stands a good chance at repelling squirrels, anybody with That One Friend Who Puts Sriracha on Everything can tell you that a taste for spicy food can be acquired easily enough. Indeed, while the initial sensitivity to capsaicin differs from individual to individual, mammals can become desensitized to the unpleasant sensations associated with TRPV1 receptor activation, and can actually develop a preference for pungency.

 

Becoming acclimated to capsaicin via desensitizing TRPV1 receptors can open up a new world of chili pepper-related culinary possibilities, but quieting these receptors can have other effects. These receptors are activated by higher temperatures, and studies have shown that capsaicin-desensitized animals have impaired body temperature-regulating behaviors, which can make them more prone to accidental overheating. Because these receptors also convey information regarding painful physical or chemical stimuli, exposure to capsaicin has been used to better understand different types of pain in both rodents and humans alike.

 

So as we go from summer into what Chapel Hill calls “winter,” and if you feel like feeding the birds instead of the squirrels, there are a number of spicy bird foods available or you could make your own. (For those of you interested in feeding squirrels exclusively, birds are repelled by the compound methyl anthranilate, which is strangely enough a component of artificial grape flavoring.) Just keep in mind that the bolder squirrels might end up taking a liking to the spicy birdseed, but you can probably identify them easily enough by the little bottles of Sriracha that they will bring.

 

 

Peer edited by Amanda Tapia.

 

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Mirror, Mirror on the Wall: How Mirror Images of Molecules Affect Our Daily Lives

All we know around us is constructed of atoms that are connected to form molecules. The types of atoms and their arrangement can change the function and characteristics of these molecules. In some cases, two molecules that are made of the same atoms can have very different characteristics, based simply on the 3D arrangement of the connected atoms. As a result of this arrangement, molecules can be exact mirror images of each other. The characteristics of these mirror image molecules can have a significant influence on everything from the scent of fruit to a patient’s survival.

To understand the concept of mirror image molecules, we can consider our left and right hands. Both hands are made of the same components, including the palms, fingers, and knuckles, which are connected in the same order on each hand. Additionally, the shape of each hand is a mirror image of the other (observe this fact by looking at both of your hands out in front of you with the palms facing each other). However, our hands are also considered to be non-superimposable, meaning they can never perfectly line up when both palms are facing the same direction. Just like our hands, molecules can be non-superimposable, mirror images of each other. When two molecules demonstrate this relationship, they are referred to as enantiomers. Conventionally, to distinguish between these two molecules, one is labeled with the letter and the other with S (in some cases, the letters L and D are also used).

Cortney Cavanaugh

The left and right hand are mirror images of each other but are non-superimposable

With this basic overview of a fundamental concept in chemistry, we can now consider how pairs of incredibly similar-seeming molecules can differ so greatly in their function and how those differences impact our lives in a variety of ways! Though enantiomers are simply mirror images of each other, they can trigger very different responses in the human body.

The refreshing scent of citrus fruits doesn’t often bring to mind the subtleties of chemistry. Amazingly, however, a single molecule is responsible for the scent of both lemons and oranges. The next time you notice the fragrant event of your coworker peeling an orange, you can thank the molecule R-limonene for filling the room with the citrus aroma. Lemon-scented household cleaners likely contain the enantiomer molecule, S-limonene, which gives the fruit its fresh scent. Less apparent is the connection between spearmint leaves and caraway seeds. The spicy fragrance of caraway is the result of S-carvone while R-carvone is the source of the unmistakable, refreshing scent of spearmint.

The nose is not the only part of the body affected by the different properties of pairs of enantiomers. When it comes to our diets, the human body processes enantiomers of sugars differently. L-Sugars are often used in the world of diet foods as low-calorie sweeteners. The L-enantiomers of the sweet crystals are equally as flavorful as the D-enantiomers, however the body only digests D-sugars while L-sugars are left to pass straight through the body (though this efficient expulsion from the body is often viewed as a negative side effect to utilizing these molecules as sweeteners).

Cortney Cavanaugh

R-Limonene is the molecule responsible for the scent of oranges while S-limonene gives lemons their fragrance

Some food connoisseurs may argue that the effect of enantiomers on taste and scent are their most striking influence, but the nature of these pairs of related molecules also has a profound effect in medicine. There are several examples of cases in which one enantiomer of a molecule is an active drug (medication that demonstrates the desired effect) while its mirror image molecule has no effect on the body at all. In cases with more substantial consequences, the opposite enantiomer of the active drug may have an adverse effect and ultimately cause more harm than good.

When a splitting headache forces you to reach for a bottle of ibuprofen, what you are actually consuming is a mixture of both R– and S-ibuprofen. In this case, S-ibuprofen is the active enantiomer of the drug that leads to pain relief. R-Ibuprofen, although present in the pill, simply has no effect on the body. In such a case, it is not necessary to ensure that the undesired enantiomer is removed completely from the medication. However, the same cannot be said for the pain relief medication known as naproxen, sold under the brand name Aleve. S-Naproxen will cure your backache, but R-naproxen presents a danger as a liver toxin.

The subtle yet consequential differences between enantiomers of medication extend beyond that of over-the-counter pain relievers. Ethambutol is a drug prescribed to treat tuberculosis. Special care must be taken to ensure that the medication contains only S-ethambutol, as R-ethambutol causes blindness. Similarly, L-DOPA is used for the treatment of Parkinson’s disease while D-DOPA can decrease the white blood cell count of a patient and lead to an increased risk of infection, creating a new problem for the patient all together.

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Exposing patients with the wrong enantiomer of a drug can have devastating consequences

Perhaps the most infamous case of drug enantiomers causing a medical disaster occurred with thalidomide. In the late 1950s, the drug thalidomide was used in Germany as a sedative that worked efficiently to treat morning sickness in pregnant patients. While R-thalidomide demonstrated this desired effect, exposure of pregnant women to S-thalidomide caused devastating malformations in developing fetuses. The widespread use of thalidomide led to thousands of babies being born with severe limb deformities and very short life expectancies. Sadly, even medicating the women with only the R-enantiomer would not have avoided this disturbing outcome due to the fact that the body is actually capable of converting R-thalidomide to S-thalidomide. As a result of the thalidomide case, a significant amount of attention has been placed on studying the influence of different enantiomers on the body and has led to more intense drug regulation worldwide.

While some enantiomer combinations can lead to unique aromas, others have greater consequences associated with human health. In both cases however, it is truly remarkable how influential the difference in the 3D arrangement of atoms in a molecule can be. These non-superimposable, mirror image molecules have proven to be a curse and a blessing in chemistry and their unique characteristics dictate our experiences when interacting with them, even affecting our own personal health.

 

Peer edited by Salma Azam and Aminah Wali.

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Crying Over Spilt Milk Substitutes

Milk is a staple food in the American diet that has been expanding its definition for the past few decades. Cow’s milk has been facing increasing competition from plant-based milk substitutes like almond and soy milk. According to the Department of Agriculture, Americans are drinking 37% less cow’s milk today than they were 47 years ago and not surprisingly, milk prices have dipped 40% in just the past few years. It is therefore a convenient time for the dairy industry to ask the question; if it comes from a plant, can you call it milk?

Dairy proponents don’t think so and suspect that consumers are being misled by marketing of nondairy milk, which they believe appropriates milk’s reputation as a nutritious food undeservedly. Their concerns have made it to Washington with introduction of the DAIRY PRIDE Act, which would require the FDA to enforce its original definition of milk as “lacteal secretion…by the complete milking of one or more healthy cows”. If passed, we might soon be seeing almond drink or perhaps ground soybean water at the grocery store.

(Dairy Data) https://www.ers.usda.gov/data-products/dairy-data/ (Image) https://www.pexels.com/photo/white-brown-cow-234791/

Annual consumption of liquid milk in pounds per person. Source: USDA ERS

It might seem ridiculous to put so much time and energy into policing the name of a product but the truth is that a label can carry a lot of power. We can see this with the clash between the sugar and corn industries. The sugar industry started seeing declining sales with the introduction of the cheaper and more stable high-fructose corn syrup. Sugar extracted from sugar cane or beets was considered natural and when products that switched from using this type of sugar to high-fructose corn syrup started promoting their products as “all natural”, The Sugar Association petitioned the FDA to define the vague term “natural”. This was happening during a time when the demand for natural products was growing and these products were assumed to be inherently healthier than processed products. Although not explicitly stated, the sugar industry wanted to exclude high-fructose corn syrup from being considered natural in order to stay competitive with corn. This clash shows that simple words carry economic power that these industries are well aware of and are willing to exploit.

https://www.pexels.com/photo/coffee-coffee-beans-afternoon-tea-40828/

How do you take your coffee?

There are similar economic pressures underlying the semantic argument on milk but how important of a factor is a name in driving consumer choices in this scenario? Some people opt for milk substitutes for concerns on sustainability of industrial dairy operations or for animal welfare. For people like me unable to digest the lactose found in cow’s milk, the choice has already been made. Other consumers have dairy allergies, are vegan or just prefer the taste of plant-based milk alternatives. These reasons seem to be independent of any deep-rooted meaning that the term “milk” may hold in the minds of consumers. Personally, I don’t expect to stop buying vanilla flavored almond milk if it was called something else. As the sugar industry was trying to clarify the term “natural”, the dairy industry is similarly trying to regain authority over the term “milk”. However, while there was and still is considerable ambiguity over what is considered “natural”, the idea of milk is pretty clear in most people’s minds. In the fight for the niche market of what goes in your espresso or cereal, plant-based milk alternatives are catching up to cow’s milk. While it’s understandable that the dairy industry would try to mitigate losses, they might be fighting a losing battle here.

 

Peer edited by Chiungwei Huang.

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Sunscreen: Not Just for Carolina Blue Days!

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Beach trips are a common activity during the summer months. Forgetting to apply sunscreen can ruin an otherwise perfect day at the beach.

Summertime is well underway, and you may find yourself lathering on sunscreen more often – or like me, you may forget you even have a bottle sitting in your bathroom cabinet. But, there are many reasons to keep that bottle within reach.

Sunscreen is particularly important for those with certain skin types. The Fitzpatrick scale is a numerical classification of skin types that have varying responses to sunlight. For example, type I skin is pale/fair that almost always burns and never tans, while type IV mostly tans and rarely burns. However, no matter your skin type, we are all susceptible to sunburns given enough sun exposure.

What causes sunburns in the first place? The same culprit that causes tanning– more specifically, solar ultraviolet rays that reach earth. UVA (320-400nm wavelengths) is more prevalent than UVB (290-320 nm) and can reach deeper layers of the skin, but both types can wreak havoc.  In skin cells (or keratinocytes), UV exposure induces DNA damage and increases oxidative stress. Tanning is a result of increased melanin production by skin cells (or melanogenesis), which absorbs UV rays.  The long-term effects of UV damage on our skin is also known as photoaging – irregular, spotty pigmentation, wrinkling, sagging, and dryness just to name a few. (check out this paper for more).

https://commons.wikimedia.org/wiki/File:UV_and_Vis_Sunscreen.jpg

Two photographs showing the effect of applying sunscreens in visible light (left) and in UVA (right). The sunscreen on the left side of the face absorbs the UV light, protecting the skin from damage, while the skin without sunscreen directly absorbs the UV light.

Sunscreen, like the name implies, blocks UV light from penetrating the deep layers of our skin through multiple active ingredients. Inorganic particulates such as zinc oxide and titanium dioxide are particularly effective at reflecting UVA and blue light. Other organic molecules absorb UV rays, such as aromatics. Newer brands of sunscreen include compounds such as avobenzone, Helioplex, and Meroxyl SX – all are not only safe, but also beneficial to blocking UV rays on the skin.

Something else to know about sunscreen – that SPF (Sun Protection Factor) written in huge numbers on your  bottle means something after all! Officially, it is a measure of the fraction of sunburn-producing UV rays that reach the skin. For example, SPF 15 means that 1/15th of burning radiation from the sun will reach the skin assuming the correct (i.e. thick) dose of sunscreen is applied. So, if you’re Fitzpatrick scale type I skin, it’s likely that you will get a sunburn from one application of SPF 15 sunscreen while your friend, who is type III or IV, does not burn with the same application.

Here are a few tips about picking and using the right sunscreen –

  1.       According to the American Academy of Dermatology, look for a sunscreen that has an SPF of 30 or higher that provides broad-spectrum coverage against both UVA and UVB light. The FDA recommends a broad-spectrum sunscreen with SPF 15 or higher.
  2.       Apply sunscreen anytime you go outside. UV light can still penetrate the atmosphere during cloudy days or in the winter!
  3.       Use the right dose. For an average adult, use at least 1 ounce (about what you can hold in your palm, or in a single shot glass) for all sun-exposed skin.
  4.       Re-apply every 2 hours to remain protected.
  5.       Check that expiration date. The active ingredients in sunscreen degrade slowly over time, and even though newer sunscreens have stabilizers be sure to replace your sunscreen if it’s expired.

 

Peer edited by Christina Marvin.

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Should Coconut Oil be in Your Pantry?

https://www.flickr.com/photos/chiotsrun/5438923520

Coconut oil is actually not a healthy alternative to butter in cooking. Feel free to use it as a moisturizer though!

Maybe it reminds us of a warm beach vacation. Or sipping a pina colada. But whatever the reason, many Americans are making coconut oil a part of their diet.

But be warned– coconut oil is extremely high in saturated fat. In fact, 92% of the fat in coconut oil is saturated. To put this in context, the fat content of butter is 63% saturated fat.

As a nutrition researcher, I’ve spoken with many Americans about their diets, and lots of people are excited about coconut oil. I’ve heard every claim– it promotes brain health, it helps you lose weight…I could go on. The truth is, the evidence isn’t strong for any of these claims.

It’s time to set the facts straight. Let’s discuss two common “myths” around coconut oil.

Myth 1: Saturated fats from plants are less harmful than animal saturated fats. Many foods contain saturated fat, such as steak, butter, and–you guessed it–coconut oil. Some people claim that plant-based saturated fats are less harmful than saturated fats from animal sources. While differences do exist between plant-based and animal saturated fats, this claim is false. Saturated fats from red meat, butter, and coconut oil all contain carbon, hydrogen and oxygen atoms, but they contain different numbers of each of these atoms, which makes them chemically different. But that’s where the differences end.

Let’s compare butter with coconut oil. The saturated fat in coconut oil is comprised mainly of a saturated fatty acid called lauric acid (which has 12 carbon atoms, 24 hydrogen atoms, and 2 oxygen atoms). Butter consists mostly of a saturated fatty acid called palmitic acid (which contains 16 carbon atoms, 32 hydrogen atoms, and 2 oxygen atoms). So yes–the saturated fats in coconut oil and butter are different, but they actually have very similar effects on our bodies. Feeding studies show that both lauric and palmitic saturated fatty acids raise our body’s cholesterol levels, which can lead to all kinds of health conditions, including heart attacks and strokes. Additionally, scientists recently combined data from 21 studies on coconut oil and found no evidence that coconut oil should be viewed differently from other sources of saturated fat. Thus, despite the chemical differences, saturated fats have similar effects on our health.

Myth 2: Coconut oil helps you lose weight. The myth that coconut oil helps people lose weight probably comes from a study in 2008 on how the human body processes different types of stored fat. All living things store fat in two types of molecules known as triglycerides: medium-chain triglycerides (MCTs) and long-chain triglycerides (LCTs). When a human, animal, or plant needs energy, these fats are broken down. The 2008 study by Dr. Marie-Pierre St.-Onge showed that eating oil rich in MCTs can increase a person’s ability to break down fat more than oils rich in LCTs, leading to faster weight loss. Coconut oil contains MCTs, so this is seemingly great news for coconut oil supporters. But dig a little deeper, and you’ll find out that the science is much more complicated.

First off, St-Onge’s study used an oil that contained 100% MCTs. But coconut oil contains only 4% MCTs. Therefore, St.-Onge’s study cannot be generalized to coconut oil. And what’s more– St.-Onge published another study in 2017 that showed that small doses of MCTs do not help with weight loss in overweight adolescents.

Additionally, MCTs containing lauric acid (remember, this is the main fatty acid in coconut oil) are heavier than other MCTs. To give you some numbers, the average weight of a triglyceride in coconut oil is 638 grams per mole (g/mol), versus 512 g/mol in other medium-chain triglyceride oils. The heavier weight of the triglycerides in coconut oil means they are broken down by the body differently than other MCTs. (If you’d like a more detailed explanation of this process, click here.) This is another reason as to why many studies on MCTs, such as the 2008 St.-Onge study, cannot be generalized to coconut oil.

Unless you’re using coconut oil to moisturize your skin, it should not be in your pantry. The science shows that unsaturated fats—like olive oil and avocados— remain the healthiest types of fat. So you can indulge in that pina colada periodically, but my everyday advice– let’s ease up on the coconuts!

Peer Edited by JoEllen McBride

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Whole Milk, how about that?

Many of us can still remember seeing our favorite pop singers with the perfect milk mustache on commercials for “Got milk?”. Later, in the school cafeteria, we would try to recreate this perfect milk mustache with milk provided by the cafeteria for lunch. Since those seemingly blissful times, much controversy has arisen surrounding milk and its supposed benefits.

https://www.flickr.com/photos/jonathanschertzer/6769789381

Enjoy a glass of milk and cookies! Whole milk may not be an unhealthy option after all.

Milk has always been promoted as a great source of calcium and vitamin D– essential vitamins and minerals for maintaining health. However, the emphasis on these nutrients disregards the high fat, saturated fat, and lactose content of milk. To address these less desirable components of milk, the milk industry has promoted low-fat milk and fat-free milk. Furthermore, governmental nutritional guidelines, like MyPlate, also recommend three daily servings of lower fat options over whole milk. This begs the question: is reduced-fat milk healthier than whole milk? To bolster these low-fat and fat-free options, the sugar industry has biased the answer to this question by promoting research that minimizes the hazards of sugar, and casts fats as the dietary enemy. These influences have contributed to a negative public perception of fats, ideal for promoting reduced-fat milk—reduced-fat milk still has the beneficial nutrients, but no longer with dietary enemy number one: fat.

In 2013, a provocative scientific review, questioned whether the three daily servings of reduced-fat milk was an evidence-based recommendation. Turns out there is a lack evidence to support replacing whole milk with reduced-fat milk based on weight management or cardiovascular disease prevention. Rather, the authors suggest, that consumption of reduced-fat milk might cause harm if sugar or simple carbohydrates are substituted for the fat. The suggestion to replace whole milk with reduced-fat milk relies on the presupposition that consumption of reduced-fat milk will lead to a total reduction in caloric intake. However, reduced-fat foods tend to be less satiating which may lead to additional caloric consumption.  For example, because a snack that includes reduced-fat milk may be less filling than a snack with whole milk, a child eating the reduced-fat snack might compensate for the reduced feeling of satiety by eating more. If these compensatory calories are more than the difference in calories between reduced-fat and whole milk or if they come in the form of refined starches and sugars, the net result of consumption of reduced-fat milk may be increased calorie consumption and increased risk for cardiovascular disease. A low-fat diet, rich in low-fat dairy products, may not only increase hunger but also negatively impact weight loss and cardiovascular health when compared to a higher fat diet.

When considering the benefits of whole milk versus its reduced-fat counterparts, I consider how milk consumption fits into my entire diet. You cannot assess food items as singular entities since they are a part of whole diet; it is important to approach dietary recommendations holistically. This makes generalized nutrition recommendations incredibly difficult to make and easily influenced by entities with vested interests in having their products promoted over others. So, maybe let’s enjoy whole milk in moderation, how about that?

Peer edited by Tamara Vital

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