On October 11th, 2017 we learned about

What makes smoke from wildfires so bad to breathe in?

My neighborhood, while thankfully a safe distance from being actually immolated in the fires spread across northern California, is starting to look a little scary. The skies are darkened with the red tint of smoke, and trees just two blocks away are starting to be obscured by the thickening particulate. My third grader is… not taking it well. She’s nervously asking how close we are to the fires, if her aunt further north is safe, and if she should start expecting ash to start falling out of the sky, a scenario she only knows from stories about when a baby in southern California. Parental instinct leads me to try and calm her, but with at least 160,000 acres burned this week, how worried should we be about all this smoke?

Byproducts of burning plants

The smoke from forest fires has a lot of different ingredients. Trees’ and other plants’ exact combinations of cellulose, tannins, oils, waxes and more can create a wide range of chemical byproducts of a fire. Smoke from a burning forest is likely to contain carbon dioxide, carbon monoxide, water vapor, hydrocarbons, nitrogen oxides, benzene, formaldehyde, trace minerals and other particulate matter. While that may sound like a big scary list, your body can bounce back from the bigger molecules it inhales pretty well, with only temporary irritation to sensitive tissues in the eyes and respiratory tract. The items that are more worrisome are the tiny particles less than 2.5 micrometers in diameter, around 30 times thinner than a human hair. These minuscule particles can get lodged deep in your lungs, where they can cause more lasting damage to cells.

Avoiding inhalation

There are, unfortunately, a lot of health concerns with breathing in too much smoke. Older people, people with compromised hearts or lungs, and of course, growing kids, are all considered to be especially at risk when the air is too polluted. Kids with asthma are probably at the most risk, as irritation can cause their airways to close enough to completely restrict breathing, but anyone who’s lungs are either sensitive or still growing should really avoid breathing hard outdoors if at all possible. Breathing in some particulate is unavoidable— the goal is just to minimize exposure and impact.

Some folks wear dust or surgeons’ masks to try to stay safe, but most of those masks aren’t designed to block the tiny particulate that is of the most concern. Even if you do have an N-95 or P-100 respirator, it needs to fit against your face without gaps, otherwise you’ll end up sucking in particulate you were trying to filter out. Staying inside is probably a safer bet, using air conditioners to help filter the air. If that’s not an option, you may want to look for Clean Air shelters, or even climate controlled malls and businesses, as a way to avoid sucking in too much smoke.

Hazards from flaming houses

The fact that 3,500 buildings have burned down in these wildfires complicates things a bit. Houses these days are packed with a lot of plastics, which burn hot and fast, releasing more toxic and corrosive gasses like hydrogen chloride, phosgene and even hydrochloric acid. Thankfully, most of these won’t be released in high enough concentrations to affect the surrounding areas, and are more commonly issues for firefighters entering burning buildings. In those scenarios, the to big worries are carbon monoxide and cyanide, both of which are odorless, colorless and most dangerous in hot areas with restricted airflows, like a structure fire. Both chemicals restrict your body’s access and use of oxygen, and can be lethal in under ten minutes’ exposure. Again, this isn’t something you need to worry about in a smokey neighborhood downwind of a fire because concentrations each compound will probably be too low to cause that much harm, but it’s something to consider if you’re ever asked to evacuate, as staying in your home may put you and firefighters in much more risk if you need rescuing later on.

Extended influence

If all this weren’t enough, there’s a chance that wildfires are affecting you even if you can’t see the smoke. Global surveys of air quality have found that large forest fires release enough smoke to be detectable on a large scale, even beyond areas where the smoke is visible. In some cases, there are things that can be done to try to mitigate the impact of forest fires, from direct prevention to reducing carbon emissions that raise the world’s temperatures and make fires more likely in the first place.

For now, everyone’s rubbing their eyes, doing a bit more sneezing, and hoping that the fires can be contained before things get too much worse. If waiting things out feels too passive,  making donations to the people whose lives have been more directly uprooted by the fires has felt helpful as well.

Source: Wildfire Smoke: A Guide for Public Health Officials by Harriet Ammann, Robert Blaisdell, Michael Lipsett, et al., Environmental Protection Agency

On October 4th, 2017 we learned about

Pinning down the causes and effects of overly picky eaters

“Do I have eat all of it?”

My daughter looked at me, trying her best to look sad and tortured over the possibility of eating three more forkfuls of salad. The effect was slightly diminished though by her hand, which was still pinching her nose to stop herself from actually tasting her food.

“Yes, eat all of it.”

For all the groaning and whining, she did finish the serving of vegetables. Like most kids her age, she’d greatly prefer a diet strictly composed of starches and sugars, and so this melodrama wasn’t that surprising. However, it also wasn’t that bad- she’s been slowly expanding her range of palatable foods. I can’t really say that she’s a picky eater, because she will try new foods, occasionally even admitting to like them. What may seem “picky” one night might not on another, or to another parent. Because having a limited diet can have an impact on one’s health, scientists are trying to figure out what metrics can be used to classify a truly picky eater.

Figuring out what makes kids finicky

There are a lot of factors involved in a kid’s attitude towards food. Environmental feedback from parents and caregivers counts for a lot, but there’s evidence that kids all have an underlying predisposition for certain foods over others. One distinction that’s being made is cases where kids object to a meal because they don’t like the food, or if they’re objecting as a way to gain control over a situation. That’s sometimes easier said than done, as some kids seem to swing back and forth in their reactions to anything that’s not their favorite macaroni and cheese.

One truly measurable criteria may turn out to be genetics. Kids identified as “picky” by the adults in their lives had their DNA tested, with particular attention given to five genes related to taste. Out of those five, two genes were more likely to have variations in kids that turned their noses up to everything. Kids with very limited palates were most likely to have an unusual nucleotide on the TAS2R38 gene, and kids that turned meals into power struggles showed differences on their CA6 gene. Incidentally, both genes are associated with bitter taste perception, and so these kids’ objects may be tied to feeling extra sensitive to bitter flavors. Since evolution has used bitterness as a toxic defense mechanism in many species of plants, it’s not surprising that it would be an issue kids would fight about.

Minimal menu leads to damaged eyes

This doesn’t mean that picky eaters aren’t worth working with. Most veggies aren’t going to give them a dangerous dose of toxins, but it may just save them from serious vitamin deficiencies. A boy in Canada was recently brought to a hospital because his vision was deteriorating at an alarming rate, and could only make out a blur of movement if objects were dangled a foot in front of his face. Dry patches were found around the edge of his iris, and his cornea was somewhat disfigured.

Doctors eventually realized that he was severely vitamin A deficient, thanks to an extremely limited diet of lamb, pork, potatoes, apples, cucumbers and Cheerios. Without a trace of carrots, sweet potatoes, spinach or fish in his diet, the boy had essentially starved himself of a nutrient most of us don’t need to worry much about. Instead of eating his vitamin A, he was left to receive multiple doses of it intravenously, which restored much of his vision, but not all of it. At least the apples and Cheerios are helping the poor kid get some fiber.

Source: Got a picky eater? How 'nature and nurture' may be influencing eating behavior in young children, MedicalXpress.com

On October 3rd, 2017 we learned about

Dead and injured cells call for help with multiple waves of calcium signals

Owies and boo-boos are a fact of life. Even decades after we figure out how to walk, we’re still quite good at getting poked, cut or scraped with enough force to kill cells in our bodies. Fortunately, our cells have contingency plans for these events, and can spring into action around a wound to start closing it up, even without a Band-Aid! This amazing feat is something we’ve all experienced, but the exact nuts and bolts of how our cells handle it still isn’t fully understood. A new study with fluorescing proteins, high-speed cameras and super-accurate lasers has found that some of the difficulty in deciphering how our bodies heal is due to how complicated the process actually is.

A cell’s final signal

One factor that makes studying healing tricky is the speed that cells work at. In response to a wound that destroys even one cell, the surrounding tissue is “activated” by a surge in calcium ions in less than a tenth of a second. Previous studies suggested that this calcium signaling followed one of two courses. Either a dying cell releases internal fluid carrying calcium ions to nearby cells, or a signal is passed from one cell to the next at points of physical contact, which are called gap junctions. In both scenarios, the outcome would be that the healthy cells would become mobilized, moving to block up the hole left by the destroyed tissue.

So to observe how that process actually plays out, scientists had to devise a system that could track changes in calcium levels on a very tiny timescale. To make the calcium visible, scientists used fruit fly larvae that were raised with a special protein that fluoresced, or lit up, when it came in contact with calcium. So while no calcium ion would be directly observed, the ions’ path through cell proteins would glow everywhere they went. Since this happens very quickly, high-speed cameras recorded the millisecond-by-millisecond process, making it understandable to human perception. This all required an actual injury, of course, which was provided by a tiny, ultra-violet laser, capable of punching microscopic holes in a single cell at a time.

More than a single signal

The laser was fired for a single femtosecond, but that was enough to heat part of the cell, and create a cavitation bubble. The bubble is a point where pressure in a liquid suddenly drops, and then bursts, which in this case lead to non-lethal damage to the cells surrounding the laser’s target. This kicked of multiple phases of activity, starting with a burst of calcium ions pouring out of the destroyed cell. A wave of calcium increases then spread outward from the wound, mostly likely traveling between cells at gap junctions. This is all wrapped up quickly, but 45 seconds later, another wave of activity starts, spreading slower and farther than before, indicating that it’s being triggered by bigger, slower molecules. Researchers also noted that this wave only occurs when a cell has been killed, not just injured. If that weren’t enough, the next 30 minutes has even more activity. Rather than maintain the original, symmetrical flow of calcium, researchers noticed “flares” of calcium that would reach out from the injury site in a straight line, last for 10 seconds, then subside.

In the end, it seems that both models for calcium transmission were correct, but they didn’t tell the whole story on their own. The next step is to figure out what slower molecules trigger the second, bigger wave of calcium activity, as well as the intermittent “flares” into surrounding tissue. Aside from understanding how fruit fly, and human, bodies actually work, the hope is that this information will some day lead to better ways to treat injuries. We may even end up with Band-Aids that actively promote healing, even beyond the lovely placebo effect they currently provide.

Source: Cell signals that trigger wound healing are surprisingly complex, Phys.org

On September 17th, 2017 we learned about

Determining what makes microbes more drug resistant in microgravity

Future human endeavors in space may run into problems with bacteria from Earth. The microbes that cover our planet seem to be surprisingly resilient to being in space, a concern that has pushed NASA to extreme measures like destroying spacecraft to avoid contaminating new environments. Experiments on the International Space Station (ISS) suggest that we may need to develop some new medical strategies as well, as bacteria in microgravity may inadvertently make themselves more resistant to antibiotics.

Absorbing less, clumping more

In a series of experiments on the ISS, researchers observed a number of changes in Escherichia coli samples adapting to microgravity. On Earth, forces like buoyancy and sedimentation help push nutrients through bacterial cells with the help of the planet’s gravity. But in the perpetual free-fall of the ISS, these mechanisms didn’t function, leading to bacteria taking in fewer nutrients from their environments. That also meant that they had a smaller surface area to absorb medicines like antibiotics, and larger doses were needed to kill them than on Earth.

This might sound manageable, but collapsing into a more tightly packed ball wasn’t the only effect of microgravity. The E. coli on the ISS also tended to grow in clumps, which researchers worry will lead to the formation of more biofilms, which are defensive structures bacteria use to repel both medicines and immune systems. Beyond that, the microbes also grew extra outer membrane vesicles, which are small structures bacteria use to communicate with each other. This can often lead to faster infections in a body, as well as mitigate the effects of antibiotics to a degree.

Silver lining?

This may sound like the first bacterial outbreak in space will be unstoppable, but researchers are still optimistic. Understanding what microgravity does to bacteria can help us develop new techniques beyond simply increasing the doses of antibiotics. There’s a chance that further study will reveal the underlying principles that shape bacteria that may normally be obscured by the Earth’s gravity. If weaknesses can be found, this may allow us to fight bacterial infections in space and at home in new ways. It should also help us understand what happens to the bacteria we want in our bodies, since they’re needed for our immune health, digestion and more.

Source: Why bacteria 'shapeshift' in space by Jim Scott, Phys.org

On August 23rd, 2017 we learned about

Yeast, algae and urine may be astronauts’ best bet for sustenance and supplies on longer trips in space

Astronauts at the International Space Station (ISS) recently got a welcome, tasty reminder that they operate in low Earth orbit. A batch of 30 Bluebell ice cream cups were delivered on a Dragon resupply capsule, marking the end of the North American summer for people living where there are no seasons. In the future, astronauts traveling further into space, such as to Mars, won’t be able to look forward to such luxuries. Instead, there’s a good chance they’ll have to find ways to enjoy whatever their onboard yeast and algae can make out of their urine.

Recyling, not resupplying

Once a ship gets too far from Earth, astronauts won’t be able to rely on regular care packages the way they can on the ISS. Like hikers trekking deep into the woods, people making the nine-month trip to Mars will need to carry everything they might need with them when they depart. This is tough, since some items essential to nutrition, like omega-3 fatty acids, don’t have a shelf life long enough to make the trip. Growing food in space may be an option to an extent, but as tasty as space lettuce may be, growing a farm’s worth of plants won’t be efficient for a while. Instead, the answer may be to bring some very compact organisms to help do a lot of serious recycling.

Water is already heavily recycled in space, even on the conveniently located ISS. Some toilets on the station are equipped to clean astronauts urine so that potable water can be reclaimed for later use. However, other ingredients in astronaut pee may provide even more utility, such as nitrogen that can be fed to yeast. If some carbon dioxide-scrubbing algae are along for the trip, they can also be fed to the yeast, at which point astronauts will have a biological factory at their disposal to create new products. Those omega-3 fatty acids, for instance, can be created by specific strains of Yarrowia lipolytica yeast raised on algae and nitrogen, ensuring a fresh supply of nutrients for astronauts on long trips.

Producing plastics

Beyond filling astronauts’ nutritional needs, genetically modified yeasts also promise to make raw materials, like polyesters. We normally think of polyester as a component of fabrics, but it may be usable in 3D printers to make other tools and components on demand in space. There are still a number of challenges to be overcome, such as the currently-impractical volume of yeast needed to make a small plastic tool, but the hope is that these methods will be refined in the near future.

There’s still no word on a urine-fed yeast that can make ice cream for future space travelers, but don’t despair if you really wanted some truly authentic astronaut ice cream. People are already working with yeasts to make dairy proteins without cows here on Earth, so version raised on algae and urine shouldn’t be an insurmountable problem.

Source: Space savers: astronaut urine could make supplies from nutrients to tools by Nicola Davis, The Guardian

On July 23rd, 2017 we learned about

Studying babies’ brains by sampling the bacteria from their butts

Parents concerned about their infant’s future aptitude may soon be fretting over their diapers. There’s no special scent or consistency to be looking for, but scientists have found a correlation between the bacteria in babies’ poop and babies’ later performance on cognitive tests. The exact mechanism at work isn’t fully understood, but it suggests that the microorganisms that call our bodies, and especially our digestive tracts, home may somehow influence our brains.

A swath of one-year-olds had their diapers sampled and analyzed to see what microbes were living in their guts. It’s well established that our bodies are colonized by trillions of microbes, many of which are crucial to our health, helping us do everything from digest food to blocking out more harmful species of bacteria. We acquire these microbes starting at birth, and so it wasn’t surprising that one-year-olds’ microbiomes were starting to look similar to what you’d find in an adult.

Better with Bacteroides

When these babies turned two, they were then given a cognitive assessment that looked at a range of skills. These included motor control, perception and language development. The results were then compared against the bacteria that had been in these kids’ diapers the previous year to see if any particular batch of microbes matched up with higher test scores. While not a clear cause and effect, kids that had had more Bacteroides bacteria scored higher on these tests, suggesting that the microbes were somehow connected to cognitive development. Surprisingly, babies with more diverse microbiomes didn’t do as well on these tests, even though that has been previously linked to other health benefits like diabetes and asthma.

There’s no known mechanism that would allow for the bacteria to directly influence brain development at this point, but the correlation suggests this is worth looking into. Even if it turns out that the increase in Bacteroides is a side effect of something else that does directly help brains, understanding that relationship may someday prove beneficial. In the mean time, don’t worry about your baby’s poopy diapers any more than practicality already requires you to.

Source: In Baby’s Dirty Diapers, The Clues To Baby’s Brain Development, Scienmag

On June 21st, 2017 we learned about

How Zinnia Huit could summon and speak with every animal, great and small

Sciencing the Sisters Eight!

The last sister showcase her new power in The Sisters Eight is Zinnia, although it also becomes clear that she’s been using it all along. While most of her sisters have to wait their turn for their powers to manifest, Zinnia spends the entire series conversing with dogs, birds and most importantly, the family’s eight cats. However, Zinnia’s abilities go beyond being able to chat with pets in the house, as she’s also able to summon animals to her from near and far, a feat that would probably require multiple modes of communication.

Calling all critters

When Zinnia calls in her zoological cavalry, human onlookers are somehow excluded from receiving her signal. This isn’t that weird an idea, as many creatures make use of similar senses to humans, but in ranges outside our perception. Elephants, for instance, have been found to make long-distance calls to each other between 1 to 20 hertz, just below the average human’s hearing range. These low-pitched calls travel a long way though, being audible over six miles away in optimal weather. It’s unclear how Zinnia would produce such a sound, but if she could it could theoretically get the attention of everything from a pachyderm to a peacock, all of whom rely on low-frequency sound for long distance communications.

Other birds might be getting called in with magnets. If Zinnia were somehow creating a strong magnetic field from her body, she could conceivably manipulate the navigation functions of many migrating birds. The birds normally rely on sensing the Earth’s magnetic poles, but if Zinnia could somehow put out a stronger signal, she might be able to convince birds that she was their actual destination.

A final way to summon other species would be to emit a batch of pheromones. Zinnia’s Zaniness doesn’t really mention how many insects arrive at Zinnia’s behest, but bugs like moths rely on these chemicals to find each other over large distances, often to find potential mates in a relatively gigantic world. Pheromones have been found to cause insects to aggregate in a wide range of species, with Cecropia moths sometimes traveling as far as 30 miles to find a mate.

Cat chats

As cool as calling in a zoo’s worth of animals is, it’s still noteworthy that Zinnia regularly converses with cats. Cats are famous for being less socially oriented than other domesticated animals like dogs, but that doesn’t mean they don’t pay attention to what humans might have to say. After all, cats don’t meow to communicate with each other as much as they do it for the people in their lives, which indicates a pretty solid effort to share their thoughts with us, even if those thoughts seem to mostly concern when they’d like to be let in or out the front door.

If you’re not Zinnia, there are still ways to try to “speak” with your cat. Body language counts for a lot, and training a cat to do specific tasks is likely to work better if it’s built around gestures instead of vocal cues alone. Following this idea, facial expressions count for a lot with cats, and learning to read them can help you understand what’s on your kitten’s mind. Some expressions probably what mean what you’d guess they mean based on human faces, such as signs of stress. However, a long, slow blink is tied to being relaxed and at ease, and cats will do this for humans and other cats when their stress levels are low enough. On the other hand, one thing people likely misinterpret is purring— even injured cats will purr, and so it doesn’t always mean a cat is happy with it’s situation, but is more likely a way for the cat to request your continued attention. So a purr might mean help is needed, or that continued petting is still required.

Zinnia seems to take all these concepts, and crank them up to enable even more sophisticated communication with the fauna in her life. Researchers haven’t pinned down the body language for complicated statements like “stop stealing the other cats’ food while invisible,” but we do at least know that there’s a foundation for her chats. Even if we can’t herd cats (or flocks of birds and bugs) very easily, there are definitely ways to start “speaking” with them.

Source: Your Cat Is Trying to Talk to You by Melissa Dahl, Science of Us

On May 25th, 2017 we learned about

Biological components in fabric aim to make responsive and self-repairing clothing

If your wardrobe is feeling a bit lifeless, you’ll be pleased to know that researchers are looking into adding bits of biology to clothing, turning them into dynamic, changing pieces of fabric. Unlike work to create wearable electronics, these concepts shouldn’t require any new batteries or other power sources, as evolution has primed these cells and proteins to do the work without needing to be plugged in. At this point, neither project is worried about fashion as much as function, but that’s OK when you’re talking about self-repairing, shape changing pants and shirts.

Moving with microbes

The MIT Media Lab’s Tangible Media Group has recently unveiled their “biohybrid” workout suit, which is designed to help athletes stay cool and dry during a workout. To do this, they’re basically co-opting a lot of existing concepts, but putting them together in a new, shirt-shaped way. The cooling is still handled by sweat evaporating off the body to cool down, but that sweaty skin will have better access to the air thanks to the clothes’ built-in bacteria.

Now most people aren’t looking for more bacteria on their body, but these microbes are actually built into the fabric itself. Harmless bacteria like Bacillus subtilis is integrated into small flaps in the cloth, with those openings being clustered over where people sweat the most. As moisture, in this case from sweat, builds up, the bacteria naturally absorb it, and basically puff up like a wet sponge. Since they’re unevenly distributed on the clothing’s flaps, as they expand, they can cause the small flaps to curl open, exposing the sweaty skin to fresh air. Even having sweat-ports in your shirt isn’t your thing, the team is also looking at other applications for geometry-shifting bacteria, like lampshades that open up when exposed to heat, or shades that close in response to ambient humidity.

Sealed by squid proteins

If you just don’t like holes in your clothes, chemists at the U.S. Naval Research Laboratory in Washington, D.C. have got you covered, albeit covered in squid proteins. Squid suction-cups have been found to be very adaptable, and can basically be reshaped and fused into shapes needed to help the squid grab hold of prey. Researchers have now isolated the proteins that make this possible, and are looking into using it on common fabrics, like linen or wool.

The most pressing use for this idea is to help protective clothing, like hazmat suits, be repaired more easily, although there is interest in expanding it to wider public use as well. Since the proteins can basically “glue” two pieces of fabric together with water and some pressure, there’s a chance that it could someday be used to patch up small tears in clothes in washing machine.

For now, both sets of biologically-enhanced clothes aren’t available for general use, but as growing proteins and bacteria becomes more common in commercial processes, we might soon have clothes that really are closer to a second skin.

Source: MIT Has Designed a Workout Suit Covered With Living Cells to Keep You Cool by Leah Rosenbaum, Seeker

On May 10th, 2017 we learned about

Food on airplanes tastes bland because your taste perception breaks in the air

It turns out that there’s one unpleasant part of flying that’s not the airlines’ fault, at least not directly. The food served on commercial airlines has long been famous for being bland and unappetizing, although since every snack on planes is now sold at prices that would make a movie theater blush, we might not being paying attention to this as much. Still, there’s not a lot an airline can do to make food tastier, aside from make us eat it on the ground. That’s because flying at high altitudes demands an environment that basically breaks our sense of taste. Even your favorite homemade dish would taste wrong if you ate it at 30,000 feet.

The air up there

The mechanism behind this isn’t actually flying, or being in the sky. Your taste buds aren’t somehow sensitive to altitude or anything. The issue is primarily how the air in a pressurized cabin messes with your sense of smell. Our perception of a flavor isn’t just what receptors are triggered on our tongues, as the exact ratios of different smells we experience as we chew provides a lot of information about what we’re eating. So when you’re stuffed up, food seems to have less flavor because you can’t detect those smells as well, which brings us back to airplanes.

While airplanes do pressurize their cabins so that you have enough oxygen to watch a movie at 30,000 feet in the air, they’re not recreating atmospheric conditions on the ground. The air pressure in the plane is closer to sitting on a 6,000- to 8,000-foot-tall mountain, meaning there’s less air to move yummy smells around the cabin. That air is also exceptionally dry, with less humidity that many deserts. This makes the mucus membranes in your sinuses drier, and less smells get registered by your brain, meaning you can’t detect a food’s flavor as well.

Upended ingredients

Weirdly, not all flavors are affected equally. The air pressure issues seem to knock out salt and sweet perception more than other types of flavors, such as umami. This is tough, since small amounts of salt are often used to enhance sweet flavors, and recipes have to be rethought to taste normal in flight. Further throwing things off is the fact that large amounts of salt bring out umami flavors, so just throwing salt at a bland snack may end up confusing things. On the other hand, this also explains why people tend to enjoy some foods more in the sky— tomato juice that’s got more umami is apparently preferred by lots of people that would never order a Bloody Mary on the ground.

Even if perfectly rebalanced recipes were concocted, and the air pressure optimized again to better match eating at sea levels, airplanes would still have an ambiance problem. As much as taste pivots on the balance of smells and flavors, our dining experience actually depends on nearly all our senses. Lighting has been found to influence how we perceive food, as does ambient sound. Light levels vary on planes, but the noise of the engines is usually a constant 85 decibels. All that sound further erodes our perception of salt and sugar, although it does seem to boost how well we can detect cardamom, lemon grass and curry.

Most of the above is unlikely to be addressed by airlines any time soon. Perfecting and mass-producing recipes that work better in the air, or retrofitting planes to feel more like an afternoon at the beach is obviously costly, possibly even more than $10 for a sandwich. So the next time you fly, just try to stay hydrated as much as possible, and try not to think about how much salt and sugar you might be eating without even enjoying it.

Source: Why does food taste different on planes? by Katia Moskvitch, BBC Future

On May 4th, 2017 we learned about

Age and “sweet tooth” genes can make eating sugar less satiating

Apologies if this makes me a bad parent, but I’m not actually sure how much sugar my kids eat each day. I do know that it makes them very excited to do so, and so every possible spike in sucrose and fructose in their daily routine is something to be negotiated, connived or at least celebrated. In the case of my four- and eight-year-old, a lot of this love for sweets is probably tied to their ages— kids taste receptors don’t work the same way adults’ do, and their growth seems to help them use those calories too. If these preferences last past their 16th birthdays though, their mom and I may be to blame, not because of parenting, but because of genetics.

Dessert-oriented DNA

Danish researchers recently isolated what they believe to be a “sweet tooth” gene, FGF21. Two variations in this gene was associated with significantly higher amounts of sugar consumption on a daily basis among the 6,500 people who participated in the study. The more common variations of the gene help produce hormones that calm neurological reward responses, making sugar less exciting to our brains after a certain amount has been eaten. People with this genetic sweet tooth don’t seem to have that same cap, and happily consume more sugar without feeling sated by it. More troubling, there may this reward connection may mean these people are also more likely to consume more alcohol and cigarettes, although that hasn’t been explicitly proven yet.

Before you start blaming FGF21 for the last candy bar you ate, don’t forget the other sweet tooth gene, SLCa2. Identified in 2008, this gene produces a protein called GLUT2, which helps move glucose around the body and help us feel full after our blood sugar levels are normalized. In lab experiments, mice with a mutation on the FGF21 gene were prone to eating more food than other mice, and there may be a correlation with Type 2 Diabetes. Overall, a change in a single amino acid correlated with as much as 25 more grams of sugar than people without the sweet tooth mutation.

Caloric counterbalance

Importantly, neither sweet tooth gene mutation really synced up with serious health problems (although these test participants’ dentists may have a different opinion on that.) People with FGF21 mutations actually had lower body mass indexes on average, so if they were somehow eating more calories due to extra sugar, they were also making up for it elsewhere in their diets. People with SLCa2 mutations were similar— while they may have eaten anywhere from 3 to 15 additional grams of sugar than other people, they weren’t consuming extra calories as a result. They were just making sugar a bigger proportion of their diet. This may be problematic if the remaining calories aren’t providing enough vitamins, antioxidants and fiber, but by itself a sweet tooth isn’t necessarily a bad thing.

Source: Crave Sugar? Maybe It's in Your Genes by Dina Fine Maron, Scientific American