TIME Cancer

You Asked: Is Sunscreen Safe — and Do I Really Need It Daily?

Is sunscreen bad for me?
Illustration by Peter Oumanski for TIME

Tons of you Google it. Our experts have the answer

Google sunscreen and toxic and see what you find. Claims that titanium dioxide is hazardous? Claims that you need vitamin D, and a little unprotected sun can give you that? Claims that chemical sunscreen can turn boy fish into girl fish? Let’s settle this for once and … for now, at least.

First thing’s first. There are two kinds of sun blockers — the physical kind, like zinc and titanium dioxide, and the chemical kind, like oxybenzone and its many cousins. They work in vastly different ways, the former blocking or “scattering” the sun’s rays (literally), and the latter causing a chemical reaction that is said to prevent damage from the sun’s UVA and UVB rays.

Start looking into it and two topics tend to come up again and again. The first surrounds titanium dioxide or zinc oxide — but only in their nanoparticle form — which means ultra-fine specs of material used in sunscreens to block or “scatter” the sun’s rays. Some scientists have voiced concern that nanoparticles may be small enough to slip past your skin’s defense barriers and into your bloodstream. Those concerns have grown louder since a recent study — albeit in rodents — found that mice injected with titanium dioxide nanoparticles developed inflammation, a marker of cell distress that has been linked to lots of terrible things that happen in the body, including aging — and cancer.

These concerns do not extend to sunscreens that contain titanium dioxide and zinc in non-nano form—although those are becoming harder to find.

The second source of concern involves other nonnano sunscreen chemicals, which work by absorbing the sun’s ultraviolet radiation as opposed to reflecting it. More animal studies have hinted at ways in which some of these chemicals could cause damage to a person’s endocrine — hormone — system. That’s the worrisome news and if you want to avoid risk, many experts contend, you are better off with nonnanoparticle forms of the physical sun blockers.

The good news: there just isn’t much hard data showing that applying these chemical sunscreens to your skin can lead to health problems, says Dr. Henry W. Lim, chairman of the Dermatology Department at Henry Ford Health System in Detroit.

Lim points out that many of the animal studies at the root of sunscreen concerns involve injecting or inhaling the chemicals, not rubbing them on your skin. “As of today there are no recorded health issues associated with sunscreen’s proper use,” he says.

But, in almost the same breath, Lim says there may still be reasons to worry about sunscreen. Specifically, he says spray-on sunscreens could present some unique dangers. That’s because, unlike lotions spread on the skin, spray-ons can be inhaled. “That could lead to very different types of risks not associated with creams,” he says, adding that the FDA is in the process of investigating the potential dangers of spray-on products. (The FDA is also, after much delay and pressure, investigating the introduction of new sunscreen ingredients that have been on the market in Europe for some time. Stay tuned for more on the bill that could change that.)

Looking past the possible dangers of sunscreen use, the benefits are far less nebulous: 1 in 3 cancers diagnosed worldwide is a skin cancer, according to the American Cancer Society. And up to 95% of malignant melanomas are caused by excessive sun damage, found research from the International Agency for Research on Cancer. “The risks associated with sun exposure are well mapped and well understood, and we have proof that using sunscreen lowers these risks,” Lim stresses.

“Sunburns are bad. There’s just no way around it,” says Kerry M. Hanson, a chemist at the University of California, Riverside, who has studied sunscreens extensively and has also worked with sunscreen manufacturers. “Protecting oneself from sunburn is critical to prevent skin cancers later in life,” she says. And to protect against sunburn, Hanson says sunscreen is proved to be effective — if it’s applied properly.

A recent study from the University of Queensland in Australia found people who followed proper sunscreen-application practices on a daily basis developed roughly 50% fewer melanomas than those who were left alone to use (or not use) sunscreen as they saw fit. Similar research efforts have uncovered proof of sunscreen’s effectiveness at blocking the development of squamous-cell and basal-cell cancers as well.

Unfortunately, Lim says many people don’t rub on nearly enough of the stuff to protect themselves. You need to spread on 1 oz. — or about the amount that would fill a shot glass — to safeguard your whole body for just a couple hours, he says. And that’s assuming you’re not sweating or swimming, in which case you need to apply more frequently.

In the end, he says the greatest danger of sunscreen may be that it provides people with a false sense of security against the sun’s dangers. “Just because you rub some on in the morning doesn’t mean you’re safe spending all day in the sun,” he says.

TIME You Asked

You Asked: Will Eating Before Bed Make Me Fat?

What to eat at night
Illustration by Peter Oumanski for TIME

You’ve been told eating before bed is a no-no. But a little pre-slumber snack can help you sleep more soundly without packing on pounds—if you reach for the right foods.

Especially if you tend to eat dinner a few hours before bedtime or you’re very active (or both), snacking before bed will help stabilize your blood sugar levels during the long, meal-less night, explains Stephanie Maxson, senior clinical dietician at the University of Texas’s MD Anderson Cancer Center.

Why should you care about blood sugar? As most diabetics know, blood sugar and its attendant hormones can supercharge or deflate your appetite and energy levels, as well as mess with your body’s efforts to store or burn fat. “Having low blood sugar in the morning will cause a person to feel sluggish and make it more difficult to get out of bed,” Maxson explains, adding that low blood sugar could also wake you up or otherwise disrupt your sleep in the middle of the night.

Ideally, you want to encourage stable blood sugar levels for optimal health, which will be tough to do if you’re going 10 or 12 or 14 hours without eating, Maxson says. (This is one reason she and many other nutrition experts underscore the importance of eating breakfast.)

“It’s such a big myth that you don’t need any energy for sleep,” adds Cassie Bjork, a registered dietician and founder of HealthySimpleLife.com. Not only can the right bedtime snack provide the fuel your body needs to burn calories while you sleep, but a little grub also calms the release of hunger hormones that tell your body to store fat, Bjork explains.

That said, a pint of ice cream isn’t going to do you any favors. Instead, you should be reaching for complex carbohydrates like whole wheat bread, non-starchy vegetables, popcorn, and fruit, Maxson says. These foods break down slowly, and so help stave off the blood sugar spikes or crashes that could mess with your sleep or appetite, she explains. For athletes, adding a protein like turkey or chicken to a bedtime snack can help with muscle repair during the night while also providing a hit of an essential amino acid called tryptophan, which is beneficial for sleep, Maxson says.

And don’t shy away from a little fat, which can further slow the absorption of carbohydrates into your system, Bjork says. Some avocado or peanut butter—or a splash of melted butter on your popcorn—can help if you frequently wake up hungry or tired.

Just be sure to avoid things like chips, cookies, cereal, or pretty much any traditional dessert food, advises Dr. Joan Sabaté, a professor of public health and nutrition at Loma Linda University. Because fiber and other digestion-slowing nutrients are typically stripped away from these foods during their preparation, your body absorbs them quickly and they tend to cause quick spikes in your blood sugar, which can make it tough for your to sleep, Sabaté explains.

Anything featuring caffeine—yes, that includes chocolate—is also a bad idea at bedtime, Maxson says.

TIME Infectious Disease

Spacing Out Kids’ Vaccines Can Hurt Their Health, Experts Say

Girl getting immunization
Getty Images

All those shriek-inducing pokes may seem excessive but the rewards of following national vaccination guidelines far outweigh the risks, experts say

“Like any parent, I don’t like to see my child get a shot,” says Dr. Michael J. Smith, a pediatrician at the University of Louisville who has studied immunizations and developmental health outcomes among kids. “But these vaccine schedules are in place for a reason.” Smith compares skipping or postponing one of your child’s vaccinations to not buckling him or her in during a car ride. “You never know when you’re going to get hit. And if you delay or space out your child’s shots, not only are you putting your kids at risk, but you’re putting other people’s kids at risk too.”

The urgency of Smith’s warnings are borne out in the recent outbreaks of measles and pertussis, diseases that had been almost totally eradicated in the U.S. but have made a frightening comeback since the turn of the century—right around the time two now-discredited scientific papers suggested a possible link between vaccines and autism. Dozens of subsequent studies have demonstrated there are no links between vaccinations and autism. But while stats show most parents understand the importance of immunizing their kids, research from the University of Michigan indicates plenty of moms and dads—roughly 1 in 4—worry that current immunization guidelines may overburden their babies’ tiny immune systems.

The Centers for Disease Control and Prevention (CDC) currently recommend that all healthy babies be vaccinated against 12 different diseases or viruses during the first two years of life. That’s compared to eight back in the early 1990s. Recently added to the list are vaccinations against potentially deadly illnesses like hepatitis and chicken pox.

But while the number of vaccines (and needle pricks) has grown during the last two decades, the amount of antigen in those shots, which is the substance that triggers a response from your child’s immune system, has plummeted, Smith explains. “The actual burden on your child’s immune system is far lower that it was 10 or 20 years ago, even though kids now receive more shots,” he says. That’s credited to advances in protein science and a better understanding of the way diseases and children’s immune systems interact.

In an effort to provide some answers for concerned parents, Smith and his colleagues looked at kids’ scores on tests related to motor skill, verbal memory, attention span, and several other neuropsychological factor to see if vaccine timing had any impact—good or bad—on a child’s brain development. His research shows kids vaccinated on time score the same or better than children who receive their vaccinations late or not at all.

Related research from Canada looked specifically at the immunization decisions made by parents of children diagnosed with autism. “Our study found that roughly 60 percent of parents who had a child with autism delayed or declined vaccinations for a later-born child,” says Dr. Jessica Brian, a developmental psychologist at the University of Toronto. According to Brian’s research, those children who did not receive their shots on time or altogether were slightly more likely to develop autism. “I don’t want to suggest that vaccines offer some protection against autism,” she says. “But our data show that there’s no increased risk of autism among kids who are vaccinated on time.”

Brian, Smith and other vaccine researchers repeatedly point to the Internet as a source of misinformation and, in some cases, unsubstantiated fear mongering when it comes to vaccines. Not uncommon are conspiracy theories involving pharmaceutical companies and the CDC. But travel overseas, and the picture changes slightly.

In Europe, where some diseases were never eradicated as thoroughly as they were in the U.S., health officials say there isn’t as much “too much, too soon” concern among parents when it comes to immunizations. Still, European moms and dads do harbor fears about potential vaccine side effects, says Niklas Danielsson, deputy head of the vaccine-preventable diseases program for the European Centre for Disease Prevention and Control. Danielsson says the “unprecedented success” of vaccination programs has created a generation of young parents who aren’t familiar with the reality of something like a measles outbreak, so they’re focus is on a shot’s rare risks as opposed to its many proven benefits.

The lingering presence of diseases in other countries is one of the big reasons having your children vaccinated on time is so important, says Dr. Simon Hambidge, a professor of pediatrics and epidemiology at the University of Colorado. “We live in a world of international travel, and people are coming into our country all the time who may be carrying these diseases,” Hambidge says. “Unfortunately, the vast majority of the new outbreaks we’re seeing involve unvaccinated children.”

Hambidge has looked closely at one possible vaccine side effect that has parents worried: seizures. The CDC recommends that all healthy infants receive their first measles vaccination between the ages of 12 and 15 months, and some research has linked the measles vaccine to higher rates of febrile seizures. Though frightening for parents, seizures of this type are relatively common and almost never cause lasting damage, Hambidge explains. “About one in 2,000 to 4,000 kids will experience one of these febrile seizures after receiving the measles vaccine,” he says. “But we found that that seizure rate rises to one in 1,000 or 2,000 if the measles vaccine is given late, or between 16 and 23 months of age.” Hambidge says this is just one example of how a slight deviation from the CDC’s vaccination schedule can put your child’s health at risk.

“The risk of measles is far, far more serious than the risk for febrile seizures,” Hambidge says. “Even if your child is unlucky enough to have a seizure after a vaccination, these seizures are short-lived and don’t lead to any long-term issues, while measles is a life-threatening disease.”

Despite the overwhelming amount of research and real-world evidence that points to the reliable safety of vaccines, experts acknowledge that parents will continue to worry about the chemicals and additives in immunization shots. To those who have doubts, Dr. Smith says, “Vaccines are one of the most rigorously tested and effective health products on the planet. Nothing involving them is done lightly.”

And when it comes to the CDC’s recommendations regarding vaccination schedules, he adds, “As a pediatrician and as a parent, if my family’s on vacation and we have to put off my daughter’s doctor visit, I get anxious each day that she goes unvaccinated. I think the timing is that important.”

TIME

You Asked: Are All Calories Created Equal?

Are all calories equal?
Illustration by Peter Oumanski for TIME

Kale or corn dogs, bananas or beer, a calorie is still a calorie. At least, that’s what dieters have been told for the past half-century. Now, experts don't agree

“By and large, we’ve been taking an accounting approach to weight loss,” says Dr. David Ludwig, a professor of nutrition at the Harvard School of Public Health. By that he means, health scientists have traditionally focused on the number of calories coming in versus the number of calories going out. But there are a lot of problems with that approach, he says. For one thing, it’s really tough to accurately keep track of your daily calorie intake. “Being off by just 100 calories a day could add up to a hundred pounds over a lifetime,” he says.

If burning more calories than you consume would keep you skinny, a low-fat diet should be the answer to all your diet prayers. That’s because, compared to protein or carbohydrates, fat contains roughly twice the number of calories, ounce for ounce. But Ludwig says low-fat diets have proved ineffective when it comes to losing weight. “Mediterranean or low-carbohydrate diets outperform a low-fat diet every time, and that wouldn’t be true if calories were the only measure that mattered,” he adds. (Mediterranean diets and others like the now-trendy Paleo diet are both high in fat, comparatively speaking.)

In reality, Ludwig says the body responds differently to calories from different sources. “Your weight is regulated by a complex system of genetic factors, hormonal factors, and neurological input, and not all calories affect this system the same way,” he explains.

As for fat: “Some naturally high-fat foods are among the most healthful we can eat in terms of promoting weight loss and reducing risk for diabetes and heart disease,” he explains, listing off foods like nuts, avocados, and many types of fish. “If you’re counting calories, you would want to eat these foods sparingly because they’re dense in calories. But they’re also very filing.”

Refined carbohydrates, on the other hand—like those found in white bread, cookies, crackers, and breakfast cereals—raise your blood’s level of the hormone insulin, which signals to your body that it needs to store fat cells. Also referred to as high-glycemic foods, these refined carbs pass through your digestive system quickly—which is why you can eat a whole bag of potato chips and feel hungry 15 minutes later, Ludwig says.

Dr. Richard Feinman, a professor of cell biology at the State University of New York Downstate Medical Center, compares insulin to a faucet handle. The more your blood’s amount of the hormone rises, the more the faucet opens and the more fat your body stores.

Feinman has looked at calories from the perspective of thermodynamics—or the laws that govern heat and energy. Like Ludwig, he says the idea that calories from different macronutrient sources would have the same effect on your body is silly. Put simply, it doesn’t make sense that “a calorie is a calorie” because your body uses the energy from different foods in a variety of ways, Feinman explains.

The big lesson here is that people need to look at food as not just a collection of calories, experts say. By cutting out refined carbs and eating more protein and healthy fats, which help you stay full without triggering the storage of fat cells, “You can work with, as opposed to against, your body’s internal weight-control systems,” he says. “That will make weight loss more natural and easy.”

The best part: You can put away the calculator. No more calories counting.

TIME You Asked

You Asked: Is Hot Yoga Good For You—And For Weight Loss?

Hot Yoga
Illustration by Peter Oumanski for TIME

Devoted hot yogis swear by the activity’s many benefits. Others roll their eyes and wonder: Is it even safe to work out at 104 degrees? Here's what the experts say

Start poking around for hard science on Bikram or “hot” yoga, and you’ll find something curious: There’s not much of it. “Considering how popular this is, it’s pretty shocking that our study is one of the very first published research efforts on the subject,” says Dr. Brian L. Tracy, an exercise scientist at Colorado State University.

Tracy and his team have conducted two experiments on the physical effects of Bikram yoga, which involves completing a strict series of poses over a period of 90 minutes in a room heated to 104 or 105 degrees. The first experiment included healthy (but sedentary) young adults with no yoga experience. After eight weeks and 24 Bikram sessions, Tracy says the study participants showed some modest increases in strength and muscle control, as well as a big improvement in balance. They also achieved a slight drop in body weight.

“To be honest, we were pretty surprised by the small size of the weight change, because when you’re in the Bikram studio you feel like you’re working really hard,” Tracy says. “And remember, these were people who didn’t regularly exercise before the study. We were expecting a bigger drop.”

For his follow-up experiment, Tracy hooked up experienced yogis to equipment designed to measure their heart rates, body temperatures, and energy expenditures during a typical Bikram session. That new data helped explain some of those disappointing body-weight findings: While heart rate and core temp climbed significantly (but not dangerously) during the 90-minute session, the participants’ metabolic rates—or the amount of calories their bodies burned—were roughly equivalent to those of people walking briskly.

“I think the immediate reaction is disappointment if you’re a Bikram fan,” Tracy says, adding that, if you’ve spent time reading about the activity online, you might assume you’d be shedding up to 1,000 calories per session. “But that’s not the case,” he says. His research shows men burn an average of 460 calories, while women work off about 330. “I think the heat and the difficulty of the postures combine to alter your perception of the intensity of the exercise,” he explains. On the other hand, one part of your body is getting a major workout, Tracy says. “Heart rates are quite high for the amount of work you’re doing. Quite high.”

Is that something you should worry about, though? “Potentially,” says Dr. Kim Allan Williams, president-elect of the American College of Cardiology. When you’re hot, your heart pumps large volumes of blood to the vessels in your skin where, through a process called convection, sweat is produced. “And it’s actually not the sweat, but the sweat’s evaporation that helps cool you off,” he explains. “Sweat does not evaporate efficiently in those conditions,” he adds.

What does this have to do with hot yoga? The humidity in Bikram yoga studios is supposed to be kept at 40 percent. But in reality, Tracy says it’s tough to know how often that goal is achieved or maintained. As the humidity climbs and your heart keeps working to cool you off, you’re sweating out minerals like potassium and sodium, along with H20, Williams says. “It’s the same for athletes working out in the middle of summer,” he adds. “You have to be mindful of the heat and humidity.”

To protect yourself, both Tracy and Williams say hot yoga practicers need to pay close attention to their bodies. Feelings of light-headedness, nausea, confusion, or muscle cramping—either during or after a yoga practice—are all signs that you need to take a break. That’s especially true for inexperienced yogis, whose bodies aren’t acclimated to the rigors of hot yoga, Tracy explains.

Williams also stresses the importance of hydration and nutrient replacement. “You can’t sweat out a bunch of minerals and then replace them with water alone,” he says. Dangerously low levels of potassium, sodium, and other electrolytes contribute to those scary health risks mentioned above.

Left unanswered are questions about the long-term effects of hot yoga practice, or how people with heart defects or other health conditions might react to the strenuous conditions, Tracy says.

Sweaty bodies aside, most hot yoga fans also praise the activity’s mental and psychological benefits. And a growing pile of research on yoga suggests the practice—and not just the hot varieties—may help lower stress while improving pain management and emotion regulation in ways similar to meditation.

“This isn’t something we’ve studied directly, but I do think there’s an element of mindfulness in Bikram yoga instruction,” says Emily Lindsay, who researches stress and mindfulness meditation at Carnegie Mellon University. Focusing your attention on your breathing and body posture can anchor you in the present moment and foster mindfulness, Lindsay explains. Yoga practice can also provide moments of peace without interruption from your cell phone, email, or life’s other routine distractions. It’s not farfetched to think that these components could offer yoga practitioners some psychological benefits, Lindsay says.

“Millions of people do it, and there aren’t just one or two anecdotal stories about how Bikram changes people’s lives,” Tracy says. “So there has to be something to it.”

TIME Diet/Nutrition

A Chemical In Coffee, Fries, and Baby Food Linked to Cancer, Report Says

187326070
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The research isn’t conclusive. But lab evidence suggests a type of chemical found in starchy foods cooked at high temperatures—as well as coffee and some baby foods—could promote the growth of cancer cells

The crispy brown crust that forms on your french fries or toast? Those are hot spots for a chemical called acrylamide, which forms when the sugars and amino acids found naturally in foods like potatoes and cereal grains are cooked at temperatures above 150 degrees. It’s present in cookies, crackers, coffee and some baby food that contains processed bran. And according to a new report from the European Food Safety Authority (EFSA), it’s a public health concern.

So should you worry?

Here’s what scientists know now: Lab studies involving animals have shown that diets loaded with acrylamide can cause DNA mutations that increase the risk of tumor growth and the spread of cancer cells. But studies involving people have produced “limited and inconsistent evidence” when it comes to the ties between acrylamide and cancer, the EFSA says.

While people exposed to the chemical in an industrial setting have suffered from nervous system issues like muscle weakness or limb numbness, that has little to do with your diet. “That was through inhalation and skin exposure to high levels of acrylamide at the work place, not food consumption,” stresses Marco Binaglia, a scientist who helped draft the EFSA report.

Binaglia says that, for now, it’s not possible for him or other health scientists to make diet recommendations. “We’ve identified a possible model of action that explains how acrylamide could damage DNA in a way that leads to cancer-producing cells.” But more study is needed to produce specific dietary guidelines, he adds.

For example, Binaglia says the EFSA’s coffee research only looks at acrylamide content, and does not take into account all the other possibly beneficial chemicals and compounds found in your morning joe, for instance. “A lot of questions cannot be answered right now,” Ramos adds. Similarly, the American Cancer Society (ACS) says that, based on available research, “It is not yet clear if acrylamide affects cancer risk in people.”

Despite all the unknowns, if you want to reduce your potential risk by cutting out the chemical from your diet, the ACS recommends boiling potatoes, which results in less acrylamide formation than roasting or frying. They also suggest lightly toasting your breads—no dark spots.

And as for acrylamide in coffee, says Luisa Ramos, another researcher who helped draft the report: “It’s usually found at higher levels in light roasts because it forms during the first minutes of roasting and then degrades as the roasting process continues.”

Ramos says choosing darker coffee roasts may lower your exposure. And, for concerned parents, baby foods that don’t contain processed cereal grains should have lower levels of the chemical.

TIME You Asked

You Asked: Is Biting Your Nails Dangerous — or Just Gross?

Nail Biting
Illustration by Peter Oumanski for TIME

Social stigma aside, experts say gnawing on your nails could lead to some scary health issues

You do it while you’re reading emails or watching television; the tip of a finger creeps up between your teeth, and you nibble away for a few minutes before catching yourself. Your mom always told you it was a bad habit, and you worry about coworkers eye-balling your shredded digits. But is biting your fingernails actually dangerous?

“Yes, and for a number of different reasons,” says Richard Scher, M.D., an expert on nail disorders at Weill Cornell Medical College and a member of the American Academy of Dermatology.

To begin with, your nails harbor all sorts of germs. In particular, a family of bacteria called enterobacteriaceae — which includes salmonella and E. coli — tends to thrive in the cozy crevice beneath the tips of your nails, Scher explains. When you bite your nails, those bacteria end up in your mouth and gut, where they can cause gastro-intestinal infections that lead to diarrhea and abdominal pain.

Long-term, habitual nail nibblers can also suffer from a type of infection called paronychia, Scher says. Tears or abrasions in the skin of your fingertips allow strains of bacteria or yeast to get inside. Both cause swelling, redness, and a buildup of puss around and under the nail, which has to be drained surgically and treated with antibiotics or antifungal agents, he explains.

If the infection is bacterial, the nail can also become tender and painful. “You’ll see it where every fingertip becomes inflamed,” Scher adds.

The wart virus HPV is also a common infection among nail biters, says Chris Adigun, M.D., a dermatologist at NYU Langone Medical Center. After infecting the fingers, these warts can then spread to your mouth and lips, Adigun adds.

The perils of nail biting also extend to your teeth. “Constant biting can lead to poor dental occlusion, so the biter’s teeth shift out of position or become oddly shaped,” Scher says. Biters also suffer from higher rates of gum disease and infection, he adds.

So how do you quit the habit? For a lot of people, nail biting is a manifestation of stress or psychological disorders.

“Both tend to cause teeth grinding, and your fingernails are a handy buffer.” You’ll have a hard time stopping without help from a psychiatrist or mental-health professional, he says. If your habit is mild, Scher says there are over-the-counter products you can spread on your nails that have a bitter taste. “The taste reminds you not to bite,” he explains.

TIME Germs

You Asked: Is the 5-Second Rule Legit?

The Five Second Rule
Illustration by Peter Oumanski for TIME

When food hits the floor, some say you have 5 seconds to retrieve it before filth hitches a ride. Here’s what germ experts have to say about that

Donut down! You quickly grab your grub, certain you’ve satisfied the 5-second rule with time to spare. But is your fallen food safe to eat?

Past research shows roughly 70% of women would say yes, along with 56% of men, says Paul Dawson, a food scientist at Clemson University who has lab-tested the legitimacy of the 5-second rule. Unfortunately, snacking on stuff that has touched the ground is always a risky proposition, he says.

“I compare picking up dropped food and eating it to not wearing a seat belt,” Dawson says. You could drive a lifetime without wearing a safety belt and never have an accident, but that doesn’t mean you’re safe not wearing one, he explains.

Dawson and his team tested the time it takes harmful bacteria like salmonella to transfer from various surfaces—wood, tile, carpet—to either dry foods (bread) or moist ones (bologna).

Here’s what they found: The length of time food spends on the floor does increase the amount of bacteria that latches on. Also, specific food-floor combinations (especially moist food on tile) result in a greater transfer of germs. But regardless of the snack-surface specifics, a significant amount of unhealthful gunk jumps from the ground to your food pretty much instantaneously, Dawson explains.

“I stand by the zero-second rule,” he says. “If bacteria is present on the ground, it will be transferred to your food.”

Recently, biomedical scientist Anthony Hilton and colleagues at Aston University in the UK repeated Dawson’s experiment with different sickness-causing bacteria like E. coli and Staphylococcus aureus. The results didn’t change.

“The majority of bacteria transfer to the food immediately on impact,” Hilton says. “The quicker you pick up your food, the fewer bacteria will transfer.” But that doesn’t mean a speedy recovery of your fallen treat will keep you safe from germs, he adds.

What about food falling on other surfaces—like your desk at work? It all depends on whether illness-causing bacteria are present, Dawson says. According to a University of Arizona study, the average office desk harbors hundreds of times more germs than the average office toilet seat.

Consider yourself warned.

TIME Diet/Nutrition

Fried Food Linked to Diabetes and Heart Disease—With an Asterisk

A server carries a tray with a hamburger and french fries at Bolt Burgers in Washington, DC on February 25, 2014.
A server carries a tray with a hamburger and french fries at Bolt Burgers in Washington, DC on February 25, 2014. Saul Loeb—AFP/Getty Images

Eating fried foods could raise your risk for several life-threatening diseases. But not all frying oils may pose the same health risks

The more fried food you eat, the more likely you are to suffer from Type 2 diabetes and heart disease, reveals new research. But goodies fried in some trans-fat-free oils—now offered at many restaurants since FDA cracked down on trans fats—may not present the same health hazards.

A U.S.-based study team analyzed diet and disease data collected from more than 100,000 men and women. Compared to people who ate fried food less than once a week, those who gobbled things like fries, fried chicken, or other deep-fried snacks four to six times a week saw their risk for Type 2 diabetes and coronary heart disease jump 39% and 23%, respectively. The risks rose even more for people who ate fried food on a daily basis.

Cooking oil tends to break down during the frying process—a chemical transformation that changes the oil’s fatty acid composition, explains study co-author Leah Cahill, a research fellow in nutritional sciences at the Harvard School of Public Health. Foods simmering in that degraded oil absorb fatty acids and other unhealthy compounds. That’s a problem, because those acids and compounds contribute to ballooning waist lines, unhealthy cholesterol and blood pressure changes, and higher levels of oxidative stress—all of which could explain the links between fried food consumption and higher rates of Type 2 diabetes and heart disease, Cahill says.

Still, there may be a light at the end of the tunnel for fried-food fans. Cahill says past research has hinted that trans fat-free cooking oils may not pose the same health risks. Cooking at home with fresh oils might also limit your exposure to unhealthy compounds, she adds.

Unfortunately, at this point Cahill says it’s impossible to say which fried foods are safe and which are not. “I wish I could give more-specific recommendations when it comes to healthy cooking oils. But our study is really a first take, and we need to know more before we can say what’s safe.”

While Cahill and other nutrition scientists sort things out, her research suggests you’re better off limiting your fried food intake—especially away from home, where oils are more likely to be reused.

TIME Diet/Nutrition

Don’t Drink the Maple Water: Which Health Drinks Are Actually Healthy

Green juices healthy
How healthy are these super hyped drinks? AFP via Getty Images

The popularity—and price point—of beverages touting miracle health benefits is exploding, but science doesn’t always back up the hype

Liquid nutrition is having a moment. From kombucha teas to high-priced “cleanses,” grocery stores are devoting whole aisles to a rash of new beverages that claim to energize your mind, trim your waistline, and supercharge your body. But while some offer legitimate health perks, “no drink is going to offer you a magic bullet against whatever ails you,” promises Mayo Clinic’s Katherine Zeratsky, RD, LD.

Here’s what Zeratsky and other nutrition experts have to say about the trendiest health drinks on the market:

Coconut Water
The Claim: Billed as “Mother Nature’s sports drink,” coconut water is a dehydration-slaking, nutrient-restoring alternative to plain H20 or more “synthetic” workout recovery beverages.
The Cost: $3 and up for roughly 16 oz
The Truth: Coconut water contains a lot of potassium—more than a medium-sized banana—as well as electrolytes, which help your body absorb H20, explains Manuel Villacorta, MS, RD, author of Peruvian Powerfoods. But if you’re refueling after a serious workout, coconut water alone won’t be enough to replenish what your body has lost, he adds. And if you haven’t been exercising? Don’t let the word “water” fool you into thinking this beverage isn’t caloric, Zeratsky warns. “People tend to lose track of the calories they consume in beverages. But if you’re drinking a bottle or two of coconut water a day instead of water, that extra 100 or 200 calories will add up,” she stresses.

Almond Milk

The claim: A healthy, humane alternative to cow’s milk.

The cost: $4 for a 65-oz carton

The truth: All “milks” are not created equal—especially when it comes to protein, explains Jennifer Koslo, PhD, RD. “Almond milk has about one gram of protein per serving, compared to eight or nine grams in cow’s milk,” Koslo says. Almond milk also lacks dairy’s branch amino acids, which—along with protein—aid muscle health and growth, Villacorta adds. If you’re lactose intolerant and need something to splash on your morning cereal or in your coffee, almond milk is a good choice, Koslo says. “But even if your almond milk is fortified with vitamin D and other nutrients, you’re not getting the same benefits you would from cow’s milk,” she adds. For those worried about the humane treatment of cows, stick to local and organic dairy products, Villacorta suggests.

Kombucha

The claim: Thanks to its bacteria content, this fermented “probiotic” tea bolsters your immune and digestive systems by supporting the microorganisms that live in your gut.

The cost: $4 and up for 16 oz

The truth: “More and more, we’re learning about the value of bacteria and probiotics to maintain a healthy population of microorganisms in our digestive systems,” explains Stephanie Maxson, MS, RD, a senior clinical dietician at the University of Texas MD Anderson Cancer Center. Kombucha tea—as well as other fermented foods like yogurt and kefir—are good sources of probiotic microorganisms, so they may support your digestive or immune systems. But at this point, it’s not clear which types of bacteria are necessary for optimal digestive health, Maxson says. “Because everyone’s microbiome is unique, people will react differently to different strains of bacteria.” Also, there’s some concern that people living with illness—particularly AIDS or cancer—may be at greater risk for infection from the bacteria in unpasteurized, fermented drinks like kombucha tea, Maxson says. If you’re healthy and don’t mind the cost, she recommends drinking no more than an ounce or two of kombucha a day. “It usually comes in a big bottle, which has enough bacteria to last you a week,” she says.

Green Juice

The claim: There are many varieties of this “super” beverage, but nearly all tout the same benefit: a huge helping of healthful fruits and veggies packed into a convenient, easy-to-swig package.

The cost: $3.50 (and up) for 15 oz

The Truth: Plant enzymes oxidate quickly, so your drink has to be really fresh for you to get all the ingredients’ nutritional benefits, Villacorta explains. As a result, a lot of pre-bottled, commercially sold green juices aren’t fresh enough to offer you the most bang for your buck. And even the fresh-squeezed options won’t provide the full range of nutrients you’d get from eating whole fruits and vegetables, he says.

Chia Seed Juice

The claim: Chia seeds are loaded with fiber, which supports digestion, as well as omega-3s, protein, calcium, magnesium, and antioxidants.

The cost: $3.50 for 10 oz

The truth: Chia seeds are good sources of fiber, and also contain healthy vitamins, nutrients, and some omega-3 fatty acids, says Susan Bowerman, MS, RD, assistant director of the UCLA Center for Human Nutrition. But these drinks tend to have a lot of other ingredients—like sugar—that make them high in carbs and calories, she adds. Also, it’s a lot cheaper to make your own chia seed drinks, Koslo adds. “Just add the seeds to a smoothie and save yourself some money,” she recommends.

Juice Cleanses

The claim: Whether you last a day or a week, a juice cleanse can supercharge your energy levels, help you lose weight, flush out your clogged digestive system, and sharpen your brain.

The cost: $7 to $10 for 16 oz

The truth: Drinking the juice of a fruit or vegetable is not as good for you as eating it whole, Zeratsky says. “Nearly all the fiber and a lot of the nutrients are contained in the flesh, so don’t let the marketing fool you into thinking drinking a juice is the same as eating the whole vegetable,” she warns. And while these cleanses are convenient, they’re also a lot more expensive than buying whole fruits and vegetables, Bowerman adds. “If people can afford cleanses and they want to drink them once in a while to supplement their regular diet, that’s fine. But they shouldn’t be consumed on their own for extended periods, because they’re not nutritionally complete,” she explains.

Aloe Vera Drinks

The claim: They support immune and digestive health, and aid weight loss.

The cost: $2.50 for 16 oz

The truth: “I’ve heard anecdotally that aloe vera can be good for digestion, but there’s really not much science behind it,” Koslo explains. She says there are also some reports of complications like diarrhea and cramps from drinking too much of these beverages. “No dietician is going to tell you you need to get aloe vera in your diet,” she adds. “If you want to drink it, there may be some benefits. But I would do so sparingly.”

Hemp Milk

The claim: Another vegan alternative to dairy milk, this beverage provides omega-3s and plant-based nutrients.

The cost: $6 for 32 oz

The truth: Like almond milk, you shouldn’t think of this hemp-based option as a comparable replacement for cow’s milk, Bowerman says. “Most are not as high in protein.” On the other hand, hemp milk does offer you some omega-3 fatty acids, although not the super-beneficial type found in fish, Koslo adds. “If you have a milk allergy, this could be a good alternative. But you’re not going to get the same protein and nutrients that mammalian milk offers,” she explains.

Maple Water

The claim: It’s low-cal and loaded with super-hydrating “bioactive compounds” including vitamins, nutrients, and polyphenols—some of which promote thyroid and bone health.

The cost: Roughly $3.50 for 11 oz (although it’s not yet widely available)

The truth: The product is so new that there’s little research out there on its health benefits, Villacorta says. And while there’s some research touting maple syrup as a source of healthy antioxidant compounds, that doesn’t mean maple water will offer the same compounds in nutritionally significant quantities, he says. Maple water is supposedly high in antioxidants as well as manganese, which assists thyroid health, bone strength, and vitamin absorption, says Lilian Cheung, RD, of the Harvard School of Public Health. “But these claims are not verified by scientific studies,” Cheung adds.

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