Chapter 7. Life-Span Development of the Brain and Behavior
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Mia Persson Dogs may look to humans for help in solving impossible tasks thanks to some genes previously linked to social disorders in people. Beagles with particular variants in a gene associated with autism were more likely to sidle up to and make physical contact with a human stranger, researchers report September 29 in Scientific Reports. That gene, SEZ6L, is one of five genes in a particular stretch of beagle DNA associated with sociability in the dogs, animal behaviorist Per Jensen and colleagues at Linköping University in Sweden say. Versions of four of those five genes have been linked to human social disorders such as autism, schizophrenia and aggression. “What we figure has been going on here is that there are genetic variants that tend to make dogs more sociable and these variants have been selected during domestication,” Jensen says. But other researchers say the results are preliminary and need to be confirmed by looking at other dog breeds. Previous genetic studies of dog domestication have not implicated these genes. But, says evolutionary geneticist Bridgett vonHoldt of Princeton University, genes that influence sociability are “not an unlikely target for domestication — as humans, we would be most interested in a protodog that was interested in spending time with humans.” |© Society for Science & the Public 2000 - 2016.
Jon Hamilton What rats can remember may help people who forget. Researchers are reporting evidence that rats possess "episodic memories," the kind of memories that allow us to go back in time and recall specific events. These memories are among the first to disappear in people who develop Alzheimer's disease. The finding, which appears Thursday in Current Biology, suggests that rats could offer a better way to test potential drugs for Alzheimer's. Right now, most of these drugs are tested in mice. "We need to have a way to study the exact type of memory that we think is impaired in Alzheimer's disease," says Bruce Lamb, a professor of medical and molecular genetics at Indiana University in Indianapolis. He was not involved in the study. The lack of an adequate animal model of Alzheimer's disease may be one reason drugs that seemed to work in mice have failed when given to people, Lamb says. Loss of episodic memories, especially recent ones, is a key sign of Alzheimer's, says Jonathon Crystal, an author of the study and director of the neuroscience program at Indiana University in Bloomington. "So if you visit your grandmother who has Alzheimer's, [she] isn't going to remember that you were visiting a couple of weeks ago and what you described about things that are going on in your life," he says. Crystal and a team of researchers thought rats might have some form of episodic memory. So they began doing studies that relied on the animals' remarkable ability to recognize a wide range of odors, like basil and banana and strawberry. © 2016 npr
Link ID: 22711 - Posted: 09.30.2016
By CATHERINE SAINT LOUIS Increasing numbers of children have high blood pressure, largely as a consequence of their obesity. A growing body of evidence suggests that high blood pressure may impair children’s cognitive skills, reducing their ability to remember, pay attention and organize facts. In the most comprehensive study to date, published on Thursday in The Journal of Pediatrics, 75 children ages 10 to 18 with untreated high blood pressure performed worse on several tests of cognitive function, compared with 75 peers who had normal blood pressure. The differences were subtle, and the new research does not prove that high blood pressure diminishes cognitive skills in children. Still, the findings set off alarm bells among some experts. “This study really shows there are some differences,” said Dr. David B. Kershaw, the director of pediatric nephrology at C. S. Mott Children’s Hospital at the University of Michigan, who was not involved with the research. “This was not just random chance.” Dr. Marc B. Lande, a professor of pediatric nephrology at the University of Rochester Medical Center, and his colleagues had children tested at four sites in three states, matching those with and without high blood pressure by age, maternal education, race, obesity levels and other factors. The researchers excluded children with learning disabilities and sleep problems, which can affect cognitive skills. Children with elevated blood pressure performed worse than their peers on tests of memory, processing speed and verbal skills, the researchers found. But all the scores were still in the normal range. Because of increased obesity, elevated blood pressure, also called hypertension, is no longer rare in children, though it is underdiagnosed. In a recent survey, about 3.5 percent of 14,187 children ages 3 to 18 had hypertension. © 2016 The New York Times Company
Hannah Devlin Science correspondent Scientists have found the most definitive evidence yet that some people are destined to age quicker and die younger than others - regardless of their lifestyle. The findings could explain the seemingly random and unfair way that death is sometimes dealt out, and raise the intriguing future possibility of being able to extend the natural human lifespan. “You get people who are vegan, sleep 10 hours a day, have a low-stress job, and still end up dying young,” said Steve Horvath, a biostatistician who led the research at the University of California, Los Angeles. “We’ve shown some people have a faster innate ageing rate.” A higher biological age, regardless of actual age, was consistently linked to an earlier death, the study found. For the 5% of the population who age fastest, this translated to a roughly 50% greater than average risk of death at any age. Intriguingly, the biological changes linked to ageing are potentially reversible, raising the prospect of future treatments that could arrest the ageing process and extend the human lifespan. “The great hope is that we find anti-ageing interventions that would slow your innate ageing rate,” said Horvath. “This is an important milestone to realising this dream.” Horvath’s ageing “clock” relies on measuring subtle chemical changes, in which methyl compounds attach or detach from the genome without altering the underlying code of our DNA. © 2016 Guardian News and Media Limited
By Abdul-Kareem Ahmed In the world of recreational and professional sports, many athletes—particularly in contact sports—suffer concussions. These mild traumatic brain injuries cause headaches, memory problems and confusion, but usually resolve on their own with rest. Some players, however, especially after repeated concussions, continue to experience symptoms for many months—a phenomenon termed post-concussion syndrome. A few of these players will eventually develop chronic traumatic encephalopathy (CTE), a progressive neurodegenerative disease that causes dementia symptoms similar to Alzheimer’s disease. CTE can lead to personality changes, movement problems and, sometimes, mortality. CTE is diagnosed after death because it requires postmortem examination of a player’s brain. Post-concussion syndrome, in contrast, is diagnosed based on patient symptoms. To date, doctors do not have any objective tests to determine syndrome severity or relate it to the risk of developing CTE. Now, a group of researchers from Sweden and the U.K. say they have developed such a test, reporting their findings last week in JAMA Neurology. The test measures biomarkers in the cerebrospinal fluid—the colorless liquid that supports and suspends the brain and spinal cord—that appear to provide a measure of concussion severity and CTE risk. The researchers collected cerebrospinal fluid via spinal taps from 16 professional Swedish ice hockey players and a similar number of healthy individuals. The hockey players had all experienced post-concussion syndrome, causing nine of them to retire from the game. © 2016 Scientific American,
By KEN BELSON One of the frustrations of researchers who study chronic traumatic encephalopathy, the degenerative brain disease linked to repeated head hits, is that it can be detected only in autopsies, and not in the living. Researchers, though, have been trying to solve this problem in two primary ways: by identifying biomarkers linked to the disease that show up on imaging tests in certain locations in the brain, and by trying to locate in the blood the protein that is the hallmark of the disease. On Monday, two groups of researchers said they had made what they considered small steps in developing both methods. The announcements are small parts of much larger studies that will take years to bear fruit, if they ever do. Both methods have been questioned by detractors, some of whom say the hype is getting ahead of the science. Scientists, these critics note, have spent decades trying to find ways to accurately diagnose Alzheimer’s disease, which has some of the same characteristics as C.T.E. Still, at a medical conference in Boston on Monday, Robert Stern, a professor of neurology at Boston University, said technology developed by the company Quanterix (paid for in part with a grant from the N.F.L.) had identified elevated levels of tau proteins in blood samples of 96 former football players between 40 and 69 years old, compared with only 25 people of the same age in a control group. The results, which are part of a seven-year study and are under review for publication, are preliminary because they identify only the total amount of tau in the blood, not the amount of the specific tau linked to C.T.E. Additional tests are being done in Sweden to determine the amount of the C.T.E.-related tau in the blood samples, Stern said. Even so, Stern said, the blood samples from the 96 former players suggest that absorbing repeated head hits earlier in life can lead to higher concentrations of tau in the blood later. © 2016 The New York Times Company
By CONOR DOUGHERTY SAN FRANCISCO — Every now and again, when I’m feeling a little down, I go to Baseball-Reference.com and look up the San Francisco Giants’ box score from July 29, 2012. It’s an odd choice for a Giants fan. The Los Angeles Dodgers won, 4-0, completing a weekend sweep in which they outscored the Giants by 19-3 and tied them for the lead in the National League West. The Giants went on to win the World Series that year, but that’s not why I remember the July 29 game. I remember that afternoon because my mom, in the throes of Alzheimer’s, left the house she shared with my dad in the Noe Valley neighborhood, walked four or so miles and somehow ended up at AT&T Park. Then she went inside and watched her team. It took a while for me to believe this. When Mom told me she had gone to the park — my dad barely watches baseball, so the Giants have always been a thing between me and Mom — I assumed it was an old memory misplaced on a new day. But it turned out that Sunday game did overlap with the hours she had been out, and a month or so later my dad got a credit card bill with the charge for the ticket. I can’t tell you when Mom cheered or if she managed to find her seat. All I know is Clayton Kershaw struck out seven, the Giants had five hits, and even though I’ve committed these statistics to memory, I still like looking them up. On the chance that this hasn’t been clubbed into your head by now, the Giants have won the World Series in every even-numbered year this decade. And for reasons that I choose to see as cosmic, this run of baseball dominance has tracked my mom’s descent into Alzheimer’s. The disease doesn’t take people from you in a day or a week or a season. You get years of steady disappearance, with an indeterminate end. So for me and Mom and baseball, this decade has been a long goodbye. © 2016 The New York Times Company
Link ID: 22690 - Posted: 09.24.2016
By David Z. Hambrick, Fredrik Ullén, Miriam Mosing Elite-level performance can leave us awestruck. This summer, in Rio, Simone Biles appeared to defy gravity in her gymnastics routines, and Michelle Carter seemed to harness super-human strength to win gold in the shot put. Michael Phelps, meanwhile, collected 5 gold medals, bringing his career total to 23. In everyday conversation, we say that elite performers like Biles, Carter, and Phelps must be “naturals” who possess a “gift” that “can’t be taught.” What does science say? Is innate talent a myth? This question is the focus of the new book Peak: Secrets from the New Science of Expertise by Florida State University psychologist Anders Ericsson and science writer Robert Pool. Ericsson and Pool argue that, with the exception of height and body size, the idea that we are limited by genetic factors—innate talent—is a pernicious myth. “The belief that one’s abilities are limited by one’s genetically prescribed characteristics....manifests itself in all sorts of ‘I can’t’ or ‘I’m not’ statements,” Ericsson and Pool write. The key to extraordinary performance, they argue, is “thousands and thousands of hours of hard, focused work.” To make their case, Ericsson and Pool review evidence from a wide range of studies demonstrating the effects of training on performance. In one study, Ericsson and his late colleague William Chase found that, through over 230 hours of practice, a college student was able to increase his digit span—the number of random digits he could recall—from a normal 7 to nearly 80. In another study, the Japanese psychologist Ayako Sakakibara enrolled 24 children from a private Tokyo music school in a training program designed to train “perfect pitch”—the ability to name the pitch of a tone without hearing another tone for reference. With a trainer playing a piano, the children learned to identify chords using colored flags—for example, a red flag for CEG and a green flag for DGH. Then, the children were tested on their ability to identify the pitches of individual notes until they reached a criterion level of proficiency. By the end of the study, the children had seemed to acquire perfect pitch. Based on these findings, Ericsson and Pool conclude that the “clear implication is that perfect pitch, far from being a gift bestowed upon only a lucky few, is an ability that pretty much anyone can develop with the right exposure and training.” © 2016 Scientific American
Laura Sanders In growing brains, billions of nerve cells must make trillions of precise connections. As they snake through the brain, nerve cell tendrils called axons use the brain’s stiffness to guide them on their challenging journey, a study of frog nerve cells suggests. The results, described online September 19 in Nature Neuroscience, show that along with chemical guidance signals, the brain’s physical properties help shape its connections. That insight may be key to understanding how nerve cells wire the brain, says study coauthor Kristian Franze. “I strongly believe that it’s not enough to look at chemistry,” says Franze, a mechanobiologist at the University of Cambridge. “We need to look at environmental factors, too.” The notion that physical features help guide axons is gaining momentum, says neuroscientist Samantha Butler of UCLA. “It’s a really intriguing study.” A better understanding of how nerve cells find their targets could help scientists coax new cells to grow after a spinal cord injury or design better materials for nerve cell implants. Franze and colleagues studied nerve cells from the retina of frogs. Experiments on cells in dishes suggested that axons, signal-transmitting tendrils led by tiny pioneering structures called growth cones, grew differently on hard and soft material. Axons grew longer and straighter on stiff surfaces and seemed to meander more on softer material. © Society for Science & the Public 2000 - 2016.
Keyword: Development of the Brain
Link ID: 22672 - Posted: 09.20.2016
By Catherine Caruso Most of us think little of hopping on Google Maps to look at everything from a bird’s-eye view of an entire continent to an on-the-ground view of a specific street, all carefully labeled. Thanks to a digital atlas published this week, the same is now possible with the human brain. Ed Lein and colleagues at the Allen Institute for Brain Science in Seattle have created a comprehensive, open-access digital atlas of the human brain, which was published this week in The Journal of Comparative Neurology. “Essentially what we were trying to do is to create a new reference standard for a very fine anatomical structural map of the complete human brain,” says Lein, the principal investigator on the project. “It may seem a little bit odd, but actually we are a bit lacking in types of basic reference materials for mapping the human brain that we have in other organisms like mouse or like monkey, and that is in large part because of the enormous size and complexity of the human brain.” The project, which spanned five years, focused on a single healthy postmortem brain from a 34-year-old woman. The researchers started with the big picture: They did a complete scan of the brain using two imaging techniques (magnetic resonance imaging and diffusion weighted imaging), which allowed them to capture both overall brain structure and the connectivity of brain fibers. Next the researchers took the brain and sliced it into 2,716 very thin sections for fine-scale, cellular analysis. They stained a portion of the sections with a traditional Nissl stain to gather information about general cell architecture. They then used two other stains to selectively label certain aspects of the brain, including structural elements of cells, fibers in the white matter, and specific types of neurons. © 2016 Scientific American
Hannah Devlin Science correspondent Babies born by caesarean section are more likely to be obese as adults, according to a study that suggests the way we are born could have a lasting impact on health. Birth by caesarean was linked to a 15% higher risk of obesity in children compared with vaginal birth. The scientists involved believe that babies born by caesarean miss out on exposure to bacteria in the birth canal that colonise the baby’s gut and may ultimately change the body’s metabolic rate - and even how hungry we feel. Audrey Gaskins, an epidemiologist at Harvard University and co-author of the new study, said: “Children born via C-section harbour less diverse gut bacteria and these patterns of less diversity have been linked to increased capacity for energy harvest by the gut microbiota. You can think of it as a slower metabolism.” Previous studies have found the same link, but were less able to rule out other factors, such as the mother’s weight or health. The latest research, which included 22,068 children born to 15,271 women, suggests that the link is not simply explained by overweight women or those with pregnancy complications such as high blood pressure being more likely to deliver by caesarean. The link remained after maternal weight was taken into account, and was more striking when siblings who had different types of births were compared. Within families, children born by caesarean were 64% more likely to be obese than their siblings born by vaginal delivery. “With siblings, they have the same mother and home environment so the genetics, the feeding environment, are all controlled for,” said Dr Gaskins. © 2016 Guardian News and Media Limited
By JANE E. BRODY As a woman of a certain age who consumes a well-balanced diet of all the usual food groups, including reasonable amounts of animal protein, I tend to dismiss advice to take a multivitamin supplement. I’ve been told repeatedly by nutrition experts that the overuse of dietary supplements for “nutritional insurance” has given Americans the most expensive urine in the world. I do take a daily supplement of vitamin D, based on considerable evidence of its multiple health benefits, especially for older people. However, based on advice from the National Academy of Medicine and an examination of accumulating research, I’m prompted to consider also taking a vitamin B12 supplement in hopes of protecting my aging brain. Animal protein foods — meat, fish, milk, cheese and eggs — are the only reliable natural dietary sources of B12, and I do get ample amounts of several in my regular diet. But now at age 75, I wonder whether I’m still able to reap the full benefit of what I ingest. You see, the ability to absorb B12 naturally present in foods depends on the presence of adequate stomach acid, the enzyme pepsin and a gastric protein called intrinsic factor to release the vitamin from the food protein it is attached to. Only then can the vitamin be absorbed by the small intestine. As people age, acid-producing cells in the stomach may gradually cease to function, a condition called atrophic gastritis. A century ago, researchers discovered that some people — most likely including Mary Todd Lincoln — had a condition called pernicious anemia, a deficiency of red blood cells ultimately identified as an autoimmune disease that causes a loss of stomach cells needed for B12 absorption. Mrs. Lincoln was known to behave erratically and was ultimately committed to a mental hospital. © 2016 The New York Times Company
Keyword: Development of the Brain
Link ID: 22634 - Posted: 09.06.2016
By Jesse Singal Back in 2014, a bigoted African leader put J. Michael Bailey, a psychologist at Northwestern, in a strange position. Yoweri Museveni, the president of Uganda, had been issuing a series of anti-gay tirades, and — partially fueled by anti-gay religious figures from the U.S. — was considering toughening Uganda’s anti-gay laws. The rhetoric was getting out of control: “The commercialisation of homosexuality is unacceptable,” said Simon Lokodo, Uganda’s ethics minister. “If they were doing it in their own rooms we wouldn’t mind, but when they go for children, that’s not fair. They are beasts of the forest.” Eventually, Museveni said he would table the idea of new legislation until he better understood the science of homosexuality, and agreed to lay off Uganda’s LGBT population if someone could prove to him homosexuality was innate. That’s where Bailey comes in: He’s a leading sex researcher who has published at length on the question of where sexual orientation comes from. LGBT advocates began reaching out to him to explain the science of homosexuality and, presumably, denounce Museveni for his hateful rhetoric. But “I had issues with rushing out a scientific statement that homosexuality is innate,” he said in an email, because he’s not sure that’s quite accurate. While he did write articles, such as an editorial in New Scientist, explaining why he thought Museveni’s position didn’t make sense, he stopped short of calling homosexuality innate. He also realized that in light of some recent advances in the science of sexual orientation, it was time to publish an article summing up the current state of the field — gathering together all that was broadly agreed-upon about the nature and potential origins of sexual orientation. (In the meantime, Museveni did end up signing the anti-gay legislation, justifying his decision by reasoning that homosexuality “was learned and could be unlearned.”) © 2016, New York Media LLC.
Laura Sanders An experimental drug swept sticky plaques from the brains of a small number of people with Alzheimer’s disease over the course of a year. And preliminary results hint that this cleanup may have staved off mental decline. News about the new drug, an antibody called aducanumab, led to excitement as it trickled out of recent scientific meetings. A paper published online August 31 in Nature offers a more comprehensive look at the drug’s effects. “Overall, this is the best news that we’ve had in my 25 years doing Alzheimer’s clinical research,” study coauthor Stephen Salloway of Brown University said August 30 at a news briefing. “It brings new hope for patients and families most affected by the disease.” The results are the most convincing evidence yet that an antibody can reduce amyloid in the brain, says Alzheimer’s researcherRachelle Doody of Baylor College of Medicine in Houston, who was not involved in the study. Still, experts caution that the results come from 165 people, a relatively small number. The seemingly beneficial effects could disappear in larger clinical trials, which are under way. “These new data are tantalizing, but they are not yet definitive,” says neuroscientist John Hardy of University College London. Like some other drug candidates for Alzheimer’s, aducanumab is an antibody that targets amyloid-beta, a sticky protein that accumulates in the brains of people with the disease. Delivered by intravenous injection, aducanumab appeared to get inside the brains of people with mild Alzheimer’s (average age about 73) and destroy A-beta plaques, the results suggest. After a year of exposure to the drug, A-beta levels had dropped. This reduction depended on the dose — the more drug, the bigger the decline in A-beta. In fact, people on the highest dose of the drug had almost no A-beta plaques in their brains after a year. |© Society for Science & the Public 2000 - 2016.
Link ID: 22621 - Posted: 09.01.2016
Merrit Kennedy More than 1,000 residents of a public housing complex in East Chicago, Ind., are now forced to relocate because of dangerously high lead levels in the area's soil. The West Calumet Housing Complex, which houses primarily low-income families, lies on the site of a former lead smelting company, as member station WBEZ reported. In July, the Environmental Protection Agency reported high lead levels in the soil in parts of the complex and notified the residents. The EPA advised parents to stop their kids from playing in the dirt, "to wash their children's toys regularly and to wash children's hands after they play outside." As WBEZ reported, the samples showed lead levels "three times higher than the federal safety standards and in some places even higher, much higher." After that, East Chicago Mayor Anthony Copeland "ordered the removal of 1,200 residents from the West Calumet housing project for safety concerns," according to the member station. The residents have now been informed that the 346-unit complex is set to be demolished. "Residents have been provided vouchers for temporary hotel living until their homes are done being cleaned. The residents will return to their homes for a few more months until vouchers for permanent housing are made available by the U.S. Department of Housing and Urban Development." © 2016 npr
Nicola Davis Children who suffer a traumatic brain injury, including mild concussion from a blow to the head, are less likely to do well at school and are at increased risk of early death, researchers have revealed. As adults they are also more likely to receive a disability pension, have failed to gain secondary school qualifications and nearly twice as likely to have been hospitalised for psychiatric reasons. The team analysed data from more than a million people born between 1973 and 1985, finding that around 9% had been diagnosed with at least one traumatic brain injury before the age of 25. More than 75% of these were mild injuries. The researchers compared the outcomes for these individuals with those of others who had not experienced a head injury, as well as carrying out a second comparison, where possible, with siblings who had not been injured. Once factors such as age and sex were taken into account, the team found that those diagnosed with a traumatic brain injury have an increased risk of experiencing a number of health and social problems. Those who had suffered a traumatic brain injury were 76% more likely to receive a disability pension, 58% more likely to have failed to gain secondary school qualifications and nearly twice as likely to have been hospitalised for psychiatric reasons, compared to those who had sustained no injury. When the researchers looked at patients who had siblings that had not sustained a traumatic brain injury, they found similar - although smaller - effects, suggesting that genetics could also play a role. © 2016 Guardian News and Media Limited
By PAM BELLUCK The images tell a heartbreaking story: Zika’s calamitous attack on the brains of babies — as seen from the inside. A study of brain scans and ultrasound pictures of 45 Brazilian babies whose mothers were infected with Zika in pregnancy shows that the virus can inflict serious damage to many different parts of the fetal brain beyond microcephaly, the condition of unusually small heads that has become the sinister signature of Zika. The images, published Tuesday in the journal Radiology, also suggest a grim possibility: Because some of the damage was seen in brain areas that continue to develop after birth, it may be that babies born without obvious impairment will experience problems as they grow. “It really brings to the forefront the importance of truly understanding the impact of Zika virus and the fact that we need to follow children who not only are exposed to Zika in pregnancy, but even those who don’t appear to have any complications at birth,” said Dr. Catherine Y. Spong, chief of the pregnancy and perinatology branch of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, who was not involved in the study. Most of the babies in the study were born with microcephaly, although three were not. Each also suffered other impairments, almost all of which emerge earlier than microcephaly because a smaller head is really a consequence of brain that has failed to develop fully or has been damaged along the way, experts said. “The brain that should be there is not there,” said Dr. Deborah Levine, an author of the study and a professor of radiology at Harvard Medical School in Boston. “The abnormalities that we see in the brain suggest a very early disruption of the brain development process.” © 2016 The New York Times Company
Keyword: Development of the Brain
Link ID: 22594 - Posted: 08.24.2016
Scientists and clinicians have long dreamed of helping the injured brain repair itself by creating new neurons, and an innovative NIH-funded study published today in Nature Medicine may bring this goal much closer to reality. A team of researchers has developed a therapeutic technique that dramatically increases the production of nerve cells in mice with stroke-induced brain damage. The therapy relies on the combination of two methods that show promise as treatments for stroke-induced neurological injury. The first consists of surgically grafting human neural stem cells into the damaged area, where they mature into neurons and other brain cells. The second involves administering a compound called 3K3A-APC, which the scientists have shown helps neural stem cells grown in a petri dish develop into neurons. However, it was unclear what effect the molecule, derived from a human protein called activated protein-C (APC), would have in live animals. A month after their strokes, mice that had received both the stem cells and 3K3A-APC performed significantly better on tests of motor and sensory functions compared to mice that received neither or only one of the treatments. In addition, many more of the stem cells survived and matured into neurons in the mice given 3K3A-APC. “This USC-led animal study could pave the way for a potential breakthrough in how we treat people who have experienced a stroke,” added Jim Koenig, Ph.D., a program director at the NIH’s National Institute of Neurological Disorders and Stroke (NINDS), which funded the research. “If the therapy works in humans, it could markedly accelerate the recovery of these patients.”
By Clare Wilson Taking a daily vitamin or mineral supplement is widely seen as a common-sense way of looking after yourself – a kind of insurance, like wearing a seat belt. But evidence is growing that it might not be such a healthy habit after all. The latest finding is that calcium supplements, taken by many women after the menopause to strengthen their bones, are linked to dementia. Among women who have had a stroke, taking calcium was associated with a seven-fold rise in the number who went on to have dementia. Calcium was also linked with a smaller, non-statistically significant, rise in dementia in women who had not had a stroke. The finding emerged from a study that was not a randomised trial, so it is not the most robust type of medical evidence. The researchers merely counted dementia cases in people who had chosen whether to take calcium, and so the data could be biased. But the results are striking and come on the heels of a previous study that was a randomised trial, which found a link between calcium supplements and a modestly higher risk of heart attacks – suggesting that caution over calcium is indeed warranted. If future research confirms the association with dementia, women would face a horrible dilemma: should they continue to take calcium, staving off bone weakness that can lead to fatal hip fractures, while running an increased risk of one of the most dreaded illness of ageing? So what’s going on? Team member Silke Kern at the Sahlgrenska Academy Institute of Neuroscience and Physiology in Gothenburg, Sweden, says that taking a calcium pill triggers a rapid surge in the mineral’s levels in the blood, one that you wouldn’t get from calcium in food. © Copyright Reed Business Information Ltd.
Link ID: 22588 - Posted: 08.23.2016
By KATHERINE KINZLER You may not be surprised to learn that food preference is a social matter. What we choose to eat depends on more than just what tastes good or is healthful. People in different cultures eat different things, and within a culture, what you eat can signal something about who you are. More surprising is that the sociality of food selection, it turns out, runs deep in human nature. In research published this month in the Proceedings of the National Academy of Sciences, my colleagues and I showed that even 1-year-old babies understand that people’s food preferences depend on their social or cultural group. Interestingly, we found that babies’ thinking about food preferences isn’t really about food per se. It’s more about the people eating foods, and the relationship between food choice and social groups. While it’s hard to know what babies think before they can talk, developmental psychologists have long capitalized on the fact that babies’ visual gaze is guided by their interest. Babies tend to look longer at something that is novel or surprising. Do something bizarre the next time you meet a baby, and you’ll notice her looking intently. Using this method, the psychologists Zoe Liberman, Amanda Woodward, Kathleen Sullivan and I conducted a series of studies. Led by Professor Liberman, we brought more than 200 1-year-olds (and their parents) into a developmental psychology lab, and showed them videos of people visibly expressing like or dislike of foods. For instance, one group of babies saw a video of a person who ate a food and expressed that she loved it. Next they saw a video of a second person who tried the same food and also loved it. This second event was not terribly surprising to the babies: The two people agreed, after all. Accordingly, the babies did not look for very long at this second video; it was what they expected. © 2016 The New York Times Company