TIME Research

You Asked: Are Self-Tanners Safe?

You Asked: Should I Use Spray Tanner?
Illustration by Peter Oumanski for TIME

These products are safer than sun exposure—but only if you avoid the sprays.

To bake, or to fake? It’s a classic tanning conundrum. Sitting under the sun causes skin damage and cellular changes that raise your risk for skin cancer, and even among adults under 40, melanoma rates are on the rise.

“In order to get a natural tan from ultraviolet light, your skin has to be injured,” says Dr. Darrell Rigel, a clinical professor of dermatology at New York University. You know this, and you worry about it. But unlike ultraviolet rays, sunless self-tanners don’t mean you have to damage your skin. “These products contain an ingredient that stains the outermost layer or your skin,” Rigel says.

In most cases, that ingredient is dihydroxyacetone (DHA). When it combines with amino acids in your skin, DHA causes a browning reaction—the same type of reaction that occurs when you make toast or grill meat, explains Dr. Adam Friedman, director of dermatologic research at Montefiore-Albert Einstein College of Medicine.

That may sound scary. But the browning only takes place in your skin’s “stratum corneum”—the topmost layer composed of dead cells, Friedman says. “Our bodies make a form of this stuff,” he adds, referring to DHA. “So I’m not concerned about it from as safety standpoint. When used topically, I think it’s the only safe way to have a tan appearance.”

For anyone who’s read up on self-tanners, Friedman’s statements may raise eyebrows. A few years ago, a much-cited report from ABC News raised concerns about spray-tanning salons and the risks of inhaling DHA and other self-tanning ingredients. Subsequent research supported the idea that inhaling spray-on tanning chemicals could potentially raise your risk for asthma, chronic obstructive pulmonary disease (COPD) or cancer.

“Stretched flat, your lungs are the size of a tennis court,” says Dr. Reynold Panettieri, a professor of pulmonary medicine at the University of Pennsylvania. “So inhaling these self-tanning agents could have all sorts of potential health consequences.”

But what about self-tanners you spread on your skin? The ABC News report cited Food & Drug Administration data suggesting that small amounts of DHA might seep through your skin and into your bloodstream. If true, that could also raise health concerns. But since that FDA data came to light, follow-up studies have failed to find evidence that DHA penetrates your skin’s protective barriers.

Dr. Rigel was one of several experts who voiced concern to ABC News following their DHA investigation. But when it comes to DHA in lotions, Rigel says his concerns have since been assuaged. “There’s no data to show that DHA is harmful when applied topically,” he says. “Pregnant women and children may want to avoid it just as a precaution, but this is benign stuff.”

Panettieri agrees. “Based on what we know today, DHA is really pretty safe when applied to the skin correctly,” he says. Correct application means avoiding the sensitive skin around your eyes and on your lips, as well as cuts or abrasions—more reasons to be wary of spray-on options. Panettieri says rubbing DHA into very thin or broken skin could let it enter your system. “Even if DHA got beyond the skin, any risk is hypothetical,” he’s quick to add.

Both he and Rigel say that compared to the well-established risks of sun exposure, topical self-tanning lotions are a safer option. Friedman agrees, and says his only concern is that some people might have an allergic reaction to DHA or other ingredients in self-tanners—a risk that comes with almost any cosmetic.

But Friedman adds one big warning: Self-tanners do not offer your skin any protection from sun damage. “Some people think these self-tanners act like sunscreen,” he says. “They don’t.” In fact, some research suggests DHA may actually increase the amount of damage your skin sustains from sun exposure.

Of course, new research could always surface new risks. And not as much is known about less-common tanning chemicals. But for now, if you’re craving a little color, self-tanning lotions with DHA seem to be your safest option.

TIME Research

Do LSD and Magic Mushrooms Have a Place In Medicine?

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Experts say it's hard to do research on the drugs under their current status

LSD and magic mushrooms are illegal for recreational use, but some medical experts see major benefits from the drugs. In a commentary published in the journal The BMJ on Tuesday, a London-based psychiatrist argues in favor of legally reclassifying the drugs so that they can more easily be used in medical research.

In his paper, James Rucker, a psychiatrist and honorary lecturer at the Institute of Psychiatry, Psychology and Neuroscience at King’s College London, argues that psychedelic drugs like LSD are less harmful and addictive than other controlled drugs like cocaine or heroin. But strict restrictions on the drugs make it difficult to conduct medical trials, he says.

Rucker writes that psychedelic drugs were frequently used in clinical research until they became classified as schedule 1 drugs—considered the most dangerous, and which aren’t used medically—in the UK in the late 1960s. “Hundreds of papers, involving tens of thousands of patients, presented evidence for their use as psychotherapeutic catalysts of mentally beneficial change in many psychiatric disorders, problems of personality development, recidivistic behavior, and existential anxiety,” Rucker writes.

It’s now challenging for researchers to conduct research on the drugs, largely due to stigma, cost and reluctance of funders to back such research. “These restrictions, and the accompanying bureaucracy, mean that the cost of clinical research using psychedelics is 5-10 times that of research into less restricted (but more harmful) drugs such as heroin—with no prospect that the benefits can be translated into wider medical practice,” argues Rucker.

Though Rucker is based in the UK, the United States has similar restrictions. According to the Atlantic, the world of research has in recent years seen a revival of interest in studying these drugs, but there’s currently no legislation to reclassify LSD and psilocybin, the main ingredient in magic mushrooms, for medical purposes.

Rucker says that in controlled settings like research laboratories, there’s little evidence to suggest that these can be harmful. But such drugs can be abused, and there’s some evidence to suggest that they can lead to health consequences that range from increased heart rate and nausea to memory loss among people who have abused the drugs for a long time.

“Importantly, and unlike most other drugs, the effects of hallucinogens are highly variable and unreliable, producing different effects in different people at different times,” the National Institutes of Health writes on its website. “Because of their unpredictable nature, the use of hallucinogens can be particularly dangerous.”

More research is needed to determine the safety and medical potential of psychedelic drugs —but in the UK, only four hospitals hold the expensive license necessary to conduct research on schedule 1 drugs, Rucker says.

TIME Diet/Nutrition

Here’s Why Living on a Noisy Street Could Make You Fatter

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Living next to a busy thoroughfare may affect more than just your mental well-being

The overwhelming hum from nearby traffic is often annoying, but it could also be making individuals more obese, according to new research from Sweden.

In an article featured in the Occupational and Environmental Medicine journal this week, researchers said they found that residents of Stockholm exposed regularly to noise from trains, aircraft or road traffic, all experienced growth in their respective waistlines.

For individuals that were unlucky enough to have been consistently exposed to all three categories, “the risk of a larger waist doubled from the 25% heightened risk among people exposed to only one noise source,” reports the Guardian.

The research team was unable to draw a conclusive link between noise pollution and obesity, but suggested that the increase of stress caused by audible irritants may be a possible culprit.

“Traffic noise may influence metabolic and cardiovascular functions through sleep disturbances and chronic stress,” said Andrei Pyko, lead author of the study at Sweden’s Karolinska Institutet, according to the Australian Associated Press.

And when a person’s sleep patterns are disturbed, it can easily affect “immune functions, influence the central control of appetite and energy expenditure as well as increase circulating levels of the stress hormone cortisol.”

[Guardian]

TIME Research

Living at High Altitudes May Increase SIDS Risk, Study Says

A new study looks at how residential altitude affects newborns

A new study suggests babies that live at high altitudes may be at a greater risk for Sudden Infant Death Syndrome (SIDS) compared to infants living at lower altitudes.

Each year, around 3,500 infants under age one die unexpectedly in the United States. Still, public health experts remain uncertain for why SIDS occurs.

In a new study published Monday in the journal Pediatrics, researchers sought to determine whether altitude might play a role in SIDS risk. The researchers looked at residential altitude of over 393,000 Colorado infants, as well as their birth and death certificate data between 2007 and 2012.

After accouting for a variety of complicating factors, the researchers found that babies that lived above 8,000 feet had slightly over double the risk of experiencing SIDS compared to infants that lived under 6,000 feet.

The study did not determine why higher altitudes might increase the risk, but others have suggested that hypoxia, not having enough oxygen, may play a role in SIDS. Researchers suggest the findings should be kept in mind when coaching new parents.

TIME Research

Babies Who Are Breast-Fed Are Better Protected Against Pollution, Study Finds

Human milk counters impact of airborne pollutants

In a newborn infant’s initial four months, exposure to pollutants like nitrogen dioxide and airborne particles can cause negative effects on motor and mental development, but a new study reported on in Science Daily says those effects are countered in babies who are breast-fed by their mothers.

Researchers in Spain began monitoring rural, pregnant women in 2006 and analyzed samples from 638 women and their infants at 15 months. They discovered that babies who are breast-fed did not suffer from the potentially harmful developmental impact of PM2.5 (pollution particle matter) and NO2 (nitrogen dioxide).

Read more at Science Daily.

TIME Research

The Scientific Reason Why Airplane Food Tastes Bad

It has to do with the dry cabin air

Why does airline food taste so lousy? A new study from Cornell University has come up with an answer, and it ain’t bad cookin’.

Turns out, the noisy environment inside a claustrophobic airplane cabin may actually change the way food tastes.

In the study, 48 people were handed a variety of solutions that were spiked with the five basic tastes: sweet, salty, sour, bitter and umami (basically, a Japanese word for the savory flavor found in foods like bacon, tomatoes, cheese, and soy sauce). First, the testers sipped in silence, then again, while wearing headsets that played about 85 decibels of noise, designed to mimic the hum of jet engines onboard a plane.

What the researchers found: While there wasn’t that much of a change in how the salty, sour, and bitter stuff tasted, the noisy surroundings dulled the sweet taste, while intensifying the savory one—which might explain why a meal eaten on a plane will usually seem a little, well, off.

“Our study confirmed that in an environment of loud noise, our sense of taste is compromised. Interestingly, this was specific to sweet and umami tastes, with sweet taste inhibited and umami taste significantly enhanced,” said Robin Dando, assistant professor of food science. “The multisensory properties of the environment where we consume our food can alter our perception of the foods we eat.”

This isn’t the first time airlines have tried to figure out the reason behind funky in-flight food. The Fraunhofer Institute, a research institute based in Germany, did a study on why a dish that would taste just fine on the ground would taste, “so dull in the air,” as Grant Mickles, the executive chef for culinary development of Lufthansa’s LSG Ski Chefs, put it to Conde Nast Traveler.

German researchers tried taste tests at both sea level and in a pressurized condition. The tests revealed that the cabin atmosphere—pressurized at 8,000 feet—combined with cool, dry cabin air numbed the taste buds (kind of like when you’ve got a bad cold). In fact, the perception of saltiness and sweetness dropped by around 30% at high altitude. Multiplying the misery: The stagnant cabin dries out the mucus membranes in the nose, thus dulling the olfactory sensors that affect taste. All of which adds up to a less-than-fine dining experience.

The good news: This research may help airlines find a way to make in-the-air meals more palatable. (That is, for flights and airlines that still offer any food at all!)

The key, according to Mickles, may be using ingredients or foods that contain a lot of umami to enhance the other flavors. He may be on to something: The folks at the Lufthansa have found that passengers guzzle as much tomato juice as beer (to the tune of about 425,000 gallons a year). Turns out, cabin pressure brings out the savory taste of the red stuff.

Good to know. Now pass the earplugs—and bring on the Bloody Marys.

This article originally appeared on Health.com.

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TIME Research

Study Finds Possible Association Between Autism and Air Pollution

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Research suggests that early exposure to air pollution may have wide-ranging negative effects

A new study from the University of Pittsburgh suggests that exposure to fine particulate air pollution from pregnancy up and through the first two years of childhood may be linked with developing autism spectrum disorder (ASD).

Researchers from the University of Pittsburgh’s Graduate School of Public Health conducted “a population-based, case-control study” of families living in southwestern Pennsylvania, which included children with and without ASD, reports Science Daily.

The research team was then able to estimate an individual’s exposure to specific categories of air pollution based on where their mothers lived before, during and after pregnancy.

“There is increasing and compelling evidence that points to associations between Pittsburgh’s poor air quality and health problems, especially those affecting our children and including issues such as autism spectrum disorder and asthma,” said Grant Oliphant, president of the Heinz Endowments, which funded the research project.

However, the members of the study stressed that their findings “reflect an association” but does not ultimately prove causality.

[Science Daily]

TIME Research

This Is Why Long Commutes Can Actually Be Good for Your Mood

The 605 freeway is jammed with cars on a day when the mountains are visible in the distance, on November 5, 2014 in Los Angeles, California.
Melanie Stetson Freeman—AP The 605 freeway is jammed with cars on a day when the mountains are visible in the distance, on November 5, 2014 in Los Angeles, California.

Some people get wound up but others relish the space to think

While saddling people with a long commute is quite likely to put them in a cantankerous mood, a new study out of Australia has also found that some people actually look forward to their daily transit because it provides a bit of much-craved alone time.

Additionally, commuting can be a positive social experience; even though people generally don’t talk with each other, subtle body cues like smiles, frowns and glances help people feel more connected.

“Public transport can be an especially valuable space for being with other people. It can help prevent social isolation,” project author Dr. David Bissell told Australia National University.

But there is a flip side.

Long hours commuting can also cause distrust and depression, even altering how people interact with friends, family and colleagues, says the study.

A key takeaway from Bissell’s research is that stressful commutes directly, and negatively, impact people’s lives. The study cites examples like “tipping points where people change their route or mode of travel, or even move house.”

For the study, Dr. Bissell interviewed 53 commuters for whom commuting was a significant part of their life. He also interviewed 26 “stakeholders” like policymakers and transport advocates. He then went through two “week in the life” experiments in Australia.

“Hopefully it will be a bit of a wakeup call to employers in terms of managing this situation,” he said.

TIME Research

Rape Is Common Among Female College Freshmen, Study Shows

Demonstrators protest sexual assault on college campuses at the #YesAllWomen rally in solidarity with those affected by violence in Seattle on May 30, 2014.
Alex Garland—Demotix/Corbis Demonstrators protest sexual assault on college campuses at the #YesAllWomen rally in solidarity with those affected by violence in Seattle on May 30, 2014.

Sexual assaults and rape have reached "epidemic levels," researchers say

A new study of first-year women at a large private university in the Northeastern U.S. reveals that many freshman women have suffered some form of rape.

The study looked at 483 women (a relatively small study size) who were a representative sample of the freshman class and who volunteered to partake in the study. The women filled out questionnaires when they arrived on campus, at the end of their fall semester, at the end of their spring semester and at the end of the summer following their first year at college. The study was published Wednesday in the Journal of Adolescent Health.

Before entering college, about 18% of the women reported enduring a completed or attempted incapacitated rape (involving drugs or alcohol) since age 14, and 15% reported being victims of completed or attempted forcible rape. Over the study year, the researchers found that 9% of the women reported experiencing attempted or completed forcible rape and 15.4% reported attempted or completed incapacitated rape. Some of the women in the study reported more than one incident. At the end of the study, the lifetime experience of forcible rape was 21.7% among the women in the study, and 25.7% for incapacitated rape.

In general, rape involving drugs and alcohol was most common among the women in the study. The data also suggests that women who had already undergone a rape before entering college were more likely to report experiencing rape during their first year. “These findings are important not only for sexual assault prevention but for mental health promotion on campus as previous work has illustrated that multiple exposures to violence are strongly associated with poor mental health, including suicidality,” a corresponding editorial on the study reads. The study authors add that risky drinking behavior should be a target for prevention.

The researchers conclude that incapacitated and forcible sexual assaults and rape have reached “epidemic levels” among college women. The findings are among a small population of women, but underline that rape is not an altogether uncommon experience among young women. While it should be noted that the study looks at self-reported rapes and not clinically validated assaults, it’s also important to note that Department of Justice data suggests up to 80% of rapes and sexual assaults of female college students go unreported.

The study replicates findings in a number of other studies, which tend to find that close to 1 in 5 women in college are sexual-assault victims. But over the past year, there’s been a great deal of controversy about using the results from one study as a stand-in for a national average of college rape victims. This has been particularly true of the 1-in-5 number often cited by the White House, which comes from the 2007 Campus Sexual Assault Study of two different colleges. This new study was much, much smaller — its value should be taken as one data point to build a broad picture of sexual assault on America’s campuses.

“These data make clear that prevention programs for both men and women in both high school and college are necessary,” the study authors write. “Programs may need to address trauma-related concerns for previously victimized women.”

TIME animals

Panda Poop Suggests They Shouldn’t Eat Their Favorite Food of Bamboo

A photo taken on April 1, 2014 shows the giant panda Hao Hao eating bamboo at Pairi Daiza animal park in Brugelette, Belgium.
Virginie Lefour—AFP/Getty Images A photo taken on April 1, 2014 shows the giant panda Hao Hao eating bamboo at Pairi Daiza animal park in Brugelette, Belgium.

After 14 hours of eating bamboo, only 17% is digested

Giant pandas may be reliant on a highly specialized diet of bamboo, but new research suggests they are not actually very good at digesting their favorite meal.

Scientists in China discovered that, unlike most herbivores, a panda’s gut bacteria has not evolved to match its diet and remains more akin its omnivorous bear cousins.

The team took 121 fecal samples from 45 giant pandas — 24 adults, 16 juveniles and five cubs — and compared these with data from a previous study, which included seven wild pandas. Both studies indicated that the bears do not have plant-degrading bacteria like Ruminococcaceae and Bacteroides.

“This result is unexpected and quite interesting, because it implies the giant panda’s gut microbiota may not have well adapted to its unique diet, and places pandas at an evolutionary dilemma,” said Xiaoyan Pang, a co-author of the study in a press release.

The scientists also discovered that gut bacteria in late Autumn is quite different from spring and summer — which they hypothesize may be a result of the lack of bamboo shoots in the fall.

Pandas spend up to 14 hours per day consuming bamboo but only digest about 17% of their meal.

China’s most famous animal evolved from a species that ate both meat and plants and began to consume almost exclusively bamboo around 2 million years ago.

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