Scientists searching for ways to protect the aging brain have turned to an unusual source: sea squirts. A study in aged mice found that supplements rich in plasmalogens, molecules found in these marine animals and in the human body, were linked with better learning, healthier brain connections and lower brain inflammation. The findings sound dramatic, […]
Les radicaux libres ont mauvaise réputation. Ils endommagent l’ADN et sont associés au vieillissement et au cancer. Mais une découverte surprenante vient bousculer cette vision : certaines cellules immunitaires ont besoin de ces molécules pour s’attaquer aux tumeurs, qui ont justement trouvé le...
There’s nothing better than sinking your teeth into a sweet, creamy chocolate bar. Rats think so, too—and they may announce their chocolate-infused joy to the world at ultrasonic frequencies.
Researchers have previously linked ultrasonic rat vocalizations with different emotional and motivational states in the animals, such as in reaction to rewarding stimuli. For example, the rodents vocalize in this way when eating something sweet.
Now, a team of researchers in Japan have discovered that rats emit a particular ultrasonic vocalization while eating chocolate. Their findings are detailed in a study recently published in the journal eNeuro.
To come to this conclusion, the researchers compared ultrasonic vocalizations that rats emitted when they had access to chocolate, with those they made when they didn’t have access to the candy. The team also compared them with a chocolate-free control group of rats. Researchers then used AI to analyze the vocalizations’ acoustic features, identifying a distinct ultrasonic vocalization—officially 40 kHz inverted-U—strongly associated with chocolate snacking.
“When rats eat something delicious such as chocolate, they emit a distinct ultrasonic call that humans cannot hear,” Koshi Murata, a study co-author and researcher at the University of Fukui, said in a statement. “This call drops sharply when the brain’s opioid ‘pleasure’ system is blocked. This suggests that rats may be vocally expressing the enjoyment of eating, offering a new window into whether animals experience pleasure as we do.”
To see if this distinct vocalization was related to the tastiness of food or just eating in general, Murata and colleagues compared chocolate-eating vocalizations with the sounds the rats produced while eating regular food. And while the rats ate similar amounts of both, they emitted significantly more 40 kHz inverted-U USVs while eating chocolate.
In a separate food-choice test, the rats also demonstrated an obvious preference for chocolate: 15 out of 16 rats picked chocolate over the regular food (and can we blame them?). In two experiments, researchers also found that the vast majority of 40 kHz inverted-U USVs were emitted within one second of a feeding event.
“Our discovery suggests that animal vocalizations could serve as a real-time, non-invasive readout of internal emotional states—specifically, how much an animal is enjoying its food,” said Murata. “Such a tool would allow researchers to measure ‘pleasure’ more directly than current methods permit, and could accelerate research into the brain mechanisms that generate positive emotions.”
Understanding more about how the brain processes rewarding experiences could shed light on behaviors like overeating, as well as conditions like anhedonia, or the inability to feel pleasure and a common symptom of depression.
Losing weight is one challenge, but keeping it off while maintaining a healthy diet can be even harder. New research suggests that a Mediterranean-inspired eating plan redesigned for the American South can help adults maintain weight loss for two years while improving the nutritional quality of their diets. The program is called Med-South and was […]
Growing up, many of us remember dutifully taking a few more bites of protein (and, of course, vegetables) to appease our moms before we were allowed to progress to the sweet, carb-heavy goodness of dessert. Lately, it seems hard to say whether our moms would be delighted or horrified to see what has happened to protein since.
Just walk into any grocery store right now, and protein is everywhere. Protein water. Protein chips. You can even request protein foam on your favorite fancy latte. Somewhere, a bodybuilder is chugging a protein shake the size of a fire extinguisher as you read this. It’s safe to say this is not your mother’s protein.
To be fair, protein deserves at least some of its mom-and-jock-endorsed reputation. It helps build muscles, keeps you feeling full, and is an essential nutrient we truly can’t live without. Older adults, especially, have been told to eat more of it as they age.
“We think of protein as beneficial,” Dr. Dudley Lamming, a professor at the University of Wisconsin-Madison and lead researcher of the review, told Popular Science, “but a number of studies have started to come out showing that when you look at large populations over the course of decades, people who were eating more protein over the course of these decades were having higher rates of age-related diseases.”
A pattern in the data sparked new questions
Lamming didn’t set out looking for a problem with protein. If anything, he was surprised by a contradiction he was noticing between population data and the conventional wisdom about protein—people who ate more protein over time were showing higher rates of cancer, diabetes, and cardiovascular disease.
“The question is, how can this be?” he remembers wondering.
Proteinmaxxing is spiking prices for whey protein. Video: ‘Proteinmaxxing’: How this trend is spiking whey protein demands, @WKYCChannel3
But a smaller slice, about five or six randomized trials, tested protein restriction directly in people. Those human trials showed consistent short-term benefits: People lost weight, their fat mass declined, and in one study of people with type 2 diabetes, insulin sensitivity improved.
Lamming adds that these results do not appear to be associated with mere calorie reduction.
“In fact, because dietary protein is satiating, people in our studies and others actually ate more calories when they were on a protein-restricted diet,” he says. “But they lost weight, and that’s because energy expenditure increases.”
One hormone may explain what’s happening
To understand the potential connection between protein restriction and increased energy expenditure, Lamming’s review explored existing mouse studies on the topic. Findings from these studies indicate that when protein intake drops, the liver releases a hormone called FGF21. That hormone signals the brain, which in turn triggers what researchers call “beiging.”
“This is a process that essentially tells your fat tissue to stop simply storing fat, but actually to start metabolizing it and burning it for energy,” says Lamming.
In practice, protein restriction doesn’t mean cutting protein out altogether. Most people get about 16 to 17 percent of their calories from protein; in the studies Lamming and his team reviewed, that’s typically cut by around half, down to roughly seven to nine percent.
“We’re not talking about restricting to an unhealthy level where you’re protein insufficient,” he says. “What we’re really talking about, in most cases, is restricting down to the recommended daily allowance as reported by the World Health Organization, which is about 0.8 grams per kilogram [of body weight].”
You don’t necessarily have to restrict protein as a whole to achieve these benefits, either; mouse studies found that cutting back on specific amino acids, including methionine, isoleucine, and valine, may provide some of the same benefits in terms of fat mass, blood sugar control, and longevity.
This doesn’t necessarily mean everyone should be in a hurry to throw away their protein waffles. Lamming is careful to note that people who exercise routinely may be an exception.
“We actually think that dietary protein has negative metabolic health outcomes for sedentary people, like the general population, since most of the population is fairly sedentary,” he says. “But maybe people who are exercising need more protein to help build muscle, and maybe it wouldn’t have these negative metabolic outcomes.”
Although these findings are based only on mouse studies so far, they may suggest that working out might protect against the downsides of higher protein intake, Lamming says.
“Fortunately,” he says, “a lot of the people who are very pro-protein are also people who are exercising.”
Lamming says his team plans to test these ideas—specifically, whether protein supplementation genuinely benefits those who exercise, and whether restriction benefits those who don’t—more directly in both mice and people over the next few years.
“For your typical person who’s not engaged in exercise, we would suspect, based on our research, that eating more calories in the form of protein would be detrimental,” he says.
Lamming’s own suggestion for sedentary people: Consider skipping the protein-added version of a product when a regular option is available.
He was quick to add, however, that those who can safely exercise certainly should.
“No one’s going to argue that more exercise would be bad,” he says.
In Ask Us Anything, Popular Science answers your most outlandish, mind-burning questions, from the everyday things you’ve always wondered to the bizarre things you never thought to ask. Have something you’ve always wanted to know? Ask us.
A strange-looking sea animal may offer scientists new clues about how the brain changes with age. Researchers found that aged mice given supplements containing plasmalogens, natural fat-like molecules found in sea squirts, performed better on memory tests and showed several biological changes linked with healthier brain aging. Sea squirts are soft marine animals that attach […]
In a two-year head-to-head trial, researchers found that two very different dietary approaches produced similar changes in body weight. A Mediterranean-style eating plan adapted to Southern food preferences helped participants lose about as much weight as WeightWatchers over two years, but it produced substantially greater improvements in reported diet quality. The comparison was part of [...]
Most men are unaware that a widely consumed part of the American diet has been linked to prostate cancer risk. A new national survey found that only 20% of men knew about the reported association between dairy consumption and prostate cancer. After learning about it, 66% said they would be likely to avoid dairy products. [...]
Muscles need fuel to work, and they can use both sugar and fat for energy. But when too much fat becomes trapped inside muscle cells, this normal energy system can begin to work less efficiently. Excess fat inside skeletal muscle is sometimes called myosteatosis. It is associated with aging, inactivity, obesity and high-fat diets, and […]
What people eat throughout life may influence more than heart health, weight, and blood sugar. A growing body of research is examining whether food choices can also affect how quickly the brain changes as people grow older. This question matters because dementia already affects tens of millions of people worldwide. With no simple way to […]
In 1948, Muriel Howorth was living a relatively ordinary life in the seaside town of Eastbourne on the south coast of England when she received a letter that would completely change the trajectory of her life.
From an early age, she had wanted to take part, or as she put it, “be of use” in international affairs. During World War II, she was employed by the Ministry of Information, the government office primarily responsible for wartime publicity and propaganda in the UK.
Howorth must have been talented at promotion and publicity, because the letter that arrived in 1948—“out of the blue,” according to her personal papers—inquired if she would like to apply her talents to making atomic energy seem more friendly.
She was well-educated, but not terribly knowledgeable about atomic science, so she borrowed a book by the radiochemist Frederick Soddy, who was born in Eastbourne, titled The Interpretation of Radium. Within a few chapters, she found herself a true believer in the promise of the atom. She would devote the rest of her life to sharing the wonders of atomic science with anyone who would listen.
Nuclear energy gets a rebrand after WWII
The United States dropped atomic bombs on the Japanese cities of Hiroshima and Nagasaki on August 6 and 9, 1945, a key factor in the end of World War II. The scale of the destruction and the ongoing damage from nuclear fallout after these attacks was vast. Despite the devastation, when a Gallup poll was released in mid-August of 1945, 85 percent of Americans approved of the bombing.
The atom was more or less a mystery to the average American, and was seen both as something to be feared and a source of hope. The potential for nuclear energy seemed endless, and although the Soviet Union was America’s ally, establishing a lead over the Soviets in nuclear technology seemed prudent.
Around 1900 when this photo was taken, nearly all grapefruits were yellow. The popular Rio red grapefruit wasn’t developed until 1984 using atomic gardening. Image: Contributor / Getty Images / Rykoff Collection
Muriel Howorth’s pro-nuclear children’s book and atomic gardening
In the years after World War II, American and European scientists and heads of state agreed that there should be a focus on more productive and peaceful uses for atomic power. The letter that Howorth received in 1948 was part of this effort. She threw herself into projects that combined science education and entertainment.
Notable among these was an elaborately choreographed pantomime titled Isotopia: An Exposition on Atomic Structure. Howorth also self-published a children’s book featuring Daddy Proton, Mummy Neutron, and their electron children. Her greatest impact as an early science communicator, though, was her work in atomic gardening.
Irradiated peanuts and other miracles of atomic gardens
Applying radiation to agricultural plants was, in part, a response to wartime scarcity. Restricted rations had made people acutely aware of the possibility of food insecurity. Researchers hoped that exposure to gamma radiation might induce mutations that resulted in higher-yielding or disease-resistant crop varieties. Perhaps some of those crops might be more dense in nutrients, too.
As atomic ambassador, Howorth founded the Atomic Gardening Association and recruited hundreds of members—or, as she called them, “atomic mutation experimenters.” Soon, atomic gardening kits were available to the public. One could send away for packets of seeds from an irradiated plant. By planting these seeds and propagating multiple generations of the plants, home gardeners could test whether any useful-seeming mutations had arisen.
Howorth herself served a mutated variety of Carolina peanuts to some of her scientist friends in 1959. Their response was underwhelming, so she planted the rest of the peanuts in her garden, where they grew remarkably quickly and produced extremely large peanuts. She usually kept a handful of these extra-large peanuts tucked away in her handbag in case the opportunity arose to recruit a new member to the Atomic Gardening Association.
In the June 1961 issue of Popular Science, a story promotes buying “plant atomic energized flower and vegetable seeds” as an “amazing science buy.” Image: Popular Science, June 1961 issue
Howorth’s lasting legacy to citizen science
It’s tempting to view Howorth as a kooky eccentric. Contemporary newspaper reports of her various events and projects were certainly dismissive in tone. More accurately, she represents an early effort at addressing the gap between scientific research and public understanding.
The world was far less interconnected in her day, with no internet, no omnipresent news media, and no social media platforms. Not only that, but the idea of women as integral parts of scientific research was slow to catch on, despite pioneering work by scientists like Marie Curie and Rosalind Franklin.
Today, the same gulf exists between what scientists publish in their fields and what the average person understands. The same challenge of translating scientific language for public consumption exists for science communicators, but the tools available to them have evolved beyond recognition. You can find videos and posts by scientists explaining everything from how blimps work to what various chemical reactions look like, or from how fossils form to why black holes are so dark.
If Howorth were around today, her atomic choreography might have gone viral. As it stands, she was a wonderful example of the love of sharing knowledge with the public, and of the excitement and joy that comes with learning new things about how our world works.
In That Time When, Popular Science tells the weirdest, surprising, and little-known stories that shaped science, engineering, and innovation.
Many things change in space, including how the intestines function. Constipation is a known side effect of space travel, but until now, little has been known about why it happens. Constipation is a familiar problem for astronauts, but the biological reason it develops during spaceflight has remained uncertain. Researchers from the University of Copenhagen working [...]
A compound produced in the body after eating pomegranates improved heart function by up to 80% in experimental models of a type of heart failure with limited treatment options. For people with heart failure with preserved ejection fraction, the heart can still pump blood but struggles to relax and refill properly between beats. In experimental [...]
A lot of us like to start our days with a cup of coffee. Whether it’s a pour-over you make at home or a latte from your favorite coffee shop, many people need caffeine to wake up and feel alert.
If you rely on coffee as a productivity hack, you might be wondering if there’s a time of day that would optimize its effects on the brain. It turns out the answer isn’t that straightforward. How the body reacts to caffeine depends on factors such as age, metabolism, and tolerance. So, here’s what the experts say about how to time that cup of joe.
What effect does coffee have on the body?
Caffeine is the central stimulant found in coffee and other foods like tea, soda, and chocolate. It helps us feel more awake by blocking adenosine, a naturally occurring chemical that builds up in the brain while we’re awake. Experiencing morning grogginess, or sleep inertia, is related to residual adenosine in the brain, though other factors like your sleep quality also play a role. As adenosine builds up throughout the day, it makes us feel increasingly tired and helps signal to the brain that it’s time for sleep.
Since caffeine has a similar chemical structure to adenosine, it fits into the same receptors in the brain. When caffeine binds to these receptors, it blocks adenosine from doing its job. As a result, the brain receives fewer of the signals that make us feel tired, helping us feel more awake, alert, and energized.
Caffeine is the central stimulant found in coffee. Video: How does caffeine keep us awake? – Hanan Qasim, TED-Ed
“But this perceived energy does come at a cost,” says Dustin Lee, an assistant professor of psychiatry and behavioral science at Johns Hopkins, in an email to Popular Science. The brain adapts to these conditions incredibly well, so over time, the brain produces more adenosine receptors.
The more receptors your brain has, the more caffeine it needs to feel alert, eventually leading to caffeine tolerance and withdrawal. “Withdrawal symptoms, which I’m sure most of us have some familiarity with, include headache, irritability, fatigue, and difficulty concentrating,” Lee explains.
If you want to quit caffeine or miss your usual cup of joe, then you’re likely to experience these symptoms very quickly. They usually start within 12 to 24 hours after stopping caffeine, peak within 48 hours and resolve within two to nine days.
When should you drink coffee?
“There’s no set answer for everyone,” says Marie-Pierre St-Onge, a professor of nutritional medicine at Columbia University Medical Center, to Popular Science. It depends on your age, metabolism, and caffeine tolerance.
“Peak caffeine absorption occurs rapidly, at about 30 to 60 minutes after ingestion,” says Lee, so a simple answer to the question would be to drink coffee about an hour before whatever activity that would benefit from caffeine’s stimulating effects. If you’re going on a run, for example, you might want to get some caffeine in before heading out, says St-Onge. That’s why its use is limited by some sports governing organizations like the National Collegiate Athletic Association.
You shouldn’t really need caffeine right when you wake up, as your body should already be alert, says St-Onge. “If you’re starting to feel a slump a few hours after waking up, that would be when to drink coffee.”
Both Lee and St-Onge stress that the answer to when you should drink coffee really depends on the individual. The ability to metabolize caffeine slows down with age, so the amount of time to clear caffeine from your bloodstream gets longer as you get older. Your circadian rhythm also changes as you get older, which means you might get tired earlier in the day.
“Compounded, [these changes] make it so that you would want to consume your caffeine earlier as you get older,” explains St-Onge.
“Caffeine dose matters just as much as the time at which you drink your cup of coffee,” adds Lee.
A cup of coffee can actually have a wide range of caffeine—the dose can depend on the ratio of coffee to water, how you brewed your cup, and even bean type. And “tolerance has a major effect on caffeine’s effects, so the morning cup of coffee might serve more to partially reverse overnight caffeine withdrawal, so that should be taken into consideration as well,” he says. Basically, that means that for regular coffee drinkers, the first cup of the day is contributing to reversing the effects of not having had any caffeine since the day before.
When should you not drink coffee?
“Not too close to bedtime,” says St-Onge. If you’re finding that you’re having trouble falling asleep, make sure that you’re not drinking coffee too late in the afternoon.
Drinking coffee on an empty stomach can also be too abrasive for some people, and may lead to side effects like increased jitters and an increased urge to go to the bathroom. (Though the idea that it can lead to stomach ulcers is a myth.) If you’re someone with a sensitive stomach, try eating something alongside your cup of coffee to be safe.
So, don’t fret too much the next time you’re thinking of when to have a cup of coffee. Just remember: not too late, and not too much. Then you might become dependent on the stuff.
In Ask Us Anything, Popular Science answers your most outlandish, mind-burning questions, from the everyday things you’ve always wondered to the bizarre things you never thought to ask. Have something you’ve always wanted to know? Ask us.
A compound connected with foods such as pomegranates and walnuts could point scientists toward a new treatment for one of the most stubborn forms of heart failure. Researchers found that urolithin A helped stiff heart tissue relax and reduced several damaging changes linked to the disease. Urolithin A is not simply a nutrient that comes […]
Intelligence is an energetically expensive luxury – as the rise of artificial intelligence has reminded us. The human brain is no exception. Comprising roughly 2% of the body weight, it uses one fifth the body’s energy in the resting state – compared with less than half of this in non-human primates. A five-year-old child devotes […]
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