The Elephant Man, novelist Pearl S. Buck and Phoebus, god of the sun, all find their way into science writer Carl Zimmer’s latest book. In She Has Her Mother’s Laugh, Zimmer uses famous moments in history — and Greek mythology — to explain genetics and how researchers have come to understand heredity and try to manipulate it.
Zimmer walks through centuries of exploration, settling into stories of scientists who tried to use simplistic notions of heredity to improve the human race. While investigating inheritance, Francis Galton, who coined the term “eugenics,” noticed that notable men had notable sons. He suggested in 1865 that England’s well-being depended on a national breeding program to produce more talented people. His hereditary utopia would make a terrifying episode of TV’s Black Mirror. Galton’s work launched later efforts in the United States to erase undesirable characteristics through sterilization laws and mental capacity checks of immigrants. Eugenics also fed the Nazis’ notion of a superior race. Zimmer doesn’t shy away from the harmful impact of such research and describes the science that showed the flaws in such discriminatory thinking. With more than 550 pages, the book covers a lot of ground, from discoveries of inherited diseases like phenylketonuria to mosaics, individuals whose cells are not all genetically identical. In places, Zimmer uses the private lives of public figures to introduce advances in genetics. With so many examples, it’s hard to grasp why he included certain stories. Some parts drag a bit, others zing. We’re all familiar with Joseph Merrick, the Elephant Man. How researchers came to understand why he was deformed is fascinating. In the early 2000s, scientists discovered that several people with the same disease, now called Proteus syndrome, had mutations in the AKT1 gene important to controlling cell growth. There is current work on a drug to block the gene’s actions. Too late for Merrick, but the work offers hope for people today with the disease.
For some readers, the parts of the book that cover recent research history may feel like familiar walks down memory lane, with added context and details. Zimmer takes us back to research on Neandertals interbreeding with ancient humans (SN: 6/5/10, p. 5), Pima Indians and their high rates of type 2 diabetes, and CRISPR, the prized gene-editing tool (SN: 9/3/16, p. 22). Zimmer describes following CRISPR research as a reporter, witnessing “the beginning of something enormous.”
The book ends with cautionary tales about past attempts to toy with nature to fix environmental problems that turned into ecological disasters. Zimmer also points out future risks of gene manipulation that scientists and ethicists have just begun to consider. The next chapter on heredity, he notes, has as many warning signs as opportunities.
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LEESBURG, Va. — Astronomers watching the 2017 solar eclipse from the ground and from the air witnessed new, tantalizing features of the sun’s outer atmosphere.
Three teams have recently presented their first science results from the Great American Eclipse. Combined, the findings could help disentangle lingering solar puzzles, such as how bursts of plasma leave the sun, why the outer atmosphere, the solar corona, is so well organized and what is the nature of the corona’s magnetic field. While thousands of eclipse watchers gathered across the country last August armed with special glasses and cameras, solar physicists Adalbert Ding and Shadia Habbal and their colleagues set up a specially designed spectrometer in Mitchell, Ore. (That was one of four sites from which their team monitored the eclipse.) The team had used an earlier version of the instrument, which takes in specific wavelengths of light that can trace different coronal temperatures, to watch a solar eclipse in March 2015 from Svalbard, Norway. In both 2015 and 2017, the scientists observed evidence of relatively cool blobs of gas embedded in hot plasma in the outer corona. (The sun’s surface simmers at about 6000° Celsius, but its corona roasts at millions of degrees — and no one knows why.) Ding, of the Institute for Optics and Atomic Physics in Berlin, and Habbal, of the University of Hawaii in Honolulu, measured wavelengths of light emitted by atoms and charged particles called ions in the corona, as a proxy for the plasma’s heat. To the researchers’ astonishment, they saw blobs of plasma during both eclipses that had maintained temperatures as low as 20,000° C embedded within material in the corona that was as hot as 3.7 million degrees Celsius, Ding said at the Triennial Earth-Sun Summit on May 23. “We were very surprised,” Ding says. He thinks the cooler material may be trapped within plasma bubbles and can’t get out. “The stunning thing is that they survive.” The team also measured solar material’s Doppler shift, or the change in wavelength as the material moved toward or away from Earth. The shifts suggested that the scientists had caught a huge bubble of plasma erupting off the sun’s surface and fleeing out into space in 2015 (SN Online: 6/16/17). At the time, they thought seeing such an explosion, called a coronal mass ejection, was just luck.
If so, their luck held for the 2017 eclipse. The researchers haven’t finished processing all of their data yet, but preliminary results showed uncharged hydrogen and helium atoms fleeing the sun as far out as 3.5 solar radii from the edge of the sun’s bright disk, at speeds of about 600 kilometers per second.
In another talk at the meeting, solar physicist Amir Caspi of the Southwest Research Institute in Boulder, Colo., presented results from a different vantage point: a WB-57F aircraft flying at about 15 kilometers in altitude.
Caspi’s team was trying to see signs of magnetic waves called Alfvén waves rippling through the outer corona. Simulations of the plasma in the corona “lead you to this Velcro-looking thing, a tangled snarled mess,” Caspi said. “In fact, that’s not what we see.” Alfvén waves could smooth out the snarls, which could help explain why the material there is so neatly organized (SN Online: 8/17/17). What’s more, the waves may contribute to the mysterious coronal heating. So Caspi’s colleagues flew telescopes on a pair of NASA’s high-altitude aircraft during the eclipse to look for these waves. The results were mixed, Caspi admits, in part because the telescopes were not designed for this type of science. NASA originally commissioned them to monitor shuttle launches for issues after the space shuttle Columbia disaster in 2003 (SN: 2/8/03, p. 83).
“Our mission was the first attempt to use them for astronomy,” Caspi says.
The telescopes saw some motion in the corona that could have been waves — or could have been jitter from the planes’ motion. “They’re tantalizing, they’re definitely not random,” Caspi said. “But we don’t know yet whether this is an artifact of the corrections we had to make, or if this is really on the sun.”
The team also captured an image of the corona in infrared wavelengths, which the researchers think is the first image of its kind. Eventually, such infrared measurements could help scientists measure the corona’s magnetic field, which governs most of the corona’s behavior but has never been measured directly (SN Online: 8/16/17).
In another experiment, solar physicist Jenna Samra of Harvard University and her colleagues were on the lookout for certain infrared wavelengths in the corona that were expected to be bright enough to see from the ground.
The team measured five wavelengths, one of which had never been seen before, the team reports in the April 1 Astrophysical Journal Letters. Solar physicist and study coauthor Philip Judge of the High Altitude Observatory in Boulder had predicted in 1998 that those wavelengths, which are especially sensitive to the magnetic field, should be visible in the corona. The results can help plan future observations with the Daniel K. Inouye Solar Telescope, currently under construction in Maui, Hawaii.
Judge and other team members observed the eclipse from Casper, Wyo., and saw some of the same wavelengths (SN Online: 8/21/17), although water in Earth’s atmosphere absorbed some of the light.
Samra, however, observed the eclipse from a plane, a Gulfstream V aircraft at an altitude of 14.3 kilometers. “It was a one-of-a-kind experience. I wouldn’t trade it,” she says. “But in the moment it was terrifying, honestly.”
Fusion may have a dark side. A shadowy hypothetical process called “dark fusion” could be occurring throughout the cosmos, a new study suggests.
The standard type of fusion occurs when two atomic nuclei unite to form a new element, releasing energy in the process. “This is why the sun shines,” says physicist Sam McDermott of Fermilab in Batavia, Ill. A similar process — dark fusion — could occur with particles of dark matter, McDermott suggests in a paper published in the June 1 Physical Review Letters. If the idea is correct, the proposed phenomenon may help physicists resolve a puzzle related to dark matter — a poorly understood substance believed to bulk up the mass of galaxies. Without dark matter, scientists can’t explain how galaxies’ stars move the way they do. But some of the quirks of how dark matter is distributed within galaxy centers remain a mystery.
Dark matter is thought to be composed of reclusive particles that don’t interact much with ordinary matter — the stuff that makes up stars, planets and living creatures. That introverted nature is what makes the enigmatic particles so hard to detect. But dark matter may not be totally antisocial (SN: 3/3/18, p. 8). “Why wouldn’t the dark matter particles interact with each other? There’s really no good reason to say they wouldn’t,” says physicist Manoj Kaplinghat of the University of California, Irvine.
Scientists have suggested that dark matter particles might ricochet off one another. But the new study goes a step further, proposing that pairs of dark matter particles could fuse, forming other unknown types of dark matter particles in the process.
Such dark fusion could help explain why dark matter near the centers of galaxies is more evenly distributed than expected. In computer simulations of galaxy formation, the density of dark matter rises sharply toward a cusp in the center of a galaxy. But in reality, galaxies have a core evenly filled with dark matter. Those simulations assume dark matter particles don’t interact with one another. But dark fusion could change how the particles behave, giving them energy that would provide the oomph necessary to escape entrapment in a galaxy’s dense cusp, thereby producing an evenly filled core.
“You can kick [particles] around through this interaction, so that’s kind of cool,” says physicist Annika Peter of the Ohio State University in Columbus. But, she says, dark fusion might end up kicking the particles out of the galaxy entirely, which wouldn’t mesh with expectations: The particles could escape the halo of dark matter that scientists believe surrounds each galaxy.
For now, if fusion does have an alter ego, scientists remain in the dark.
Tropical cyclones don’t move as fast as they used to.
The fierce, swirling storms move 10 percent slower, on average, than they did nearly 70 years ago, a new study finds. Such lingering storms can potentially cause more damage by dumping even more rainfall on land beneath them.
Atmospheric scientist James Kossin examined changes in how quickly tropical cyclones, known as hurricanes in the Atlantic Ocean, moved across the planet from 1949 to 2016. Storms slowed at different rates depending on the region, with the biggest changes seen in the Northern Hemisphere, Kossin reports in the June 7 Nature. Over that same time period, the average temperature of Earth’s surface rose by about half a degree Celsius. Scientists already predict that average wind speeds will increase in tropical cyclones as ocean waters warm due to global warming (SN: 6/27/15, p. 9). The new study suggests that climate change is also altering how quickly these tropical cyclones travel across land or water.
The effect was even more pronounced as storms moved over land, with those originating in the western North Pacific, such as near Japan, slowing by 30 percent. Storms coming in from the North Atlantic – such as 2017’s Hurricane Harvey — are moving 20 percent slower over land, says Kossin, of the National Oceanic and Atmospheric Administration’s National Centers for Environmental Information in Madison, Wis. The new study makes an important link between the atmospheric effects of global warming to its effects on tropical cyclones, says atmospheric scientist Christina Patricola of the Lawrence Berkeley National Laboratory in California, who also wrote a commentary that accompanies the new paper. “Tropical cyclones tend to move along with larger-scale [atmospheric] circulation around them,” she says. “Kossin perceptively hypothesized that this overall slowdown would also affect tropical cyclones.”
It’s not clear whether the slowdown will continue into the future, or how it might vary regionally, Patricola says. Most previous work has focused on how climate change will affect the wind speeds of storms rather than how quickly they travel, known as the translation speed. “But in order to have the best information for building resilience to storms, we need to understand these other characteristics,” she says.
The cyclone slowdown is consistent with a weakening in atmospheric circulation in the tropical parts of the planet, a result of global warming, Kossin found. Global warming is also expected to increase how much water vapor the atmosphere can hold, which means storms could accumulate more moisture before releasing it in rainfall.
Slow-moving Hurricane Harvey, which dumped record levels of rain while lingering for days over southern Texas, could be a harbinger of things to come.
Suicide research is undergoing a timing shift, and not a moment too soon. A new breed of studies that track daily — and even hourly — changes in suicidal thinking is providing intriguing, although still preliminary, insights into how to identify those on the verge of trying to kill themselves.
Monitoring ways in which suicidal thoughts wax and wane over brief time periods, it turns out, can potentially strengthen suicide prevention strategies.
Digital technology has made these investigations possible. Smartphone applications alert people to report on suicidal thoughts as they arise in real-world settings. Scientists have traditionally been limited to tracking suicidal thinking over intervals of weeks, months and years, often in research labs and hospitals.
But risk factors that do a decent job of predicting the emergence of suicidal thoughts and acts over the long haul, such as persistent feelings of hopelessness, provide little help in tagging those who will become suicidal in the coming hours and days. Depression, often cited as a main driver of suicide, displays a strong link to suicidal thoughts but not to attempting or completing suicide in the near future.
Despite increasing efforts to combat suicide, U.S. suicide rates steadily rose from 1999 to 2016 (SN Online: 6/7/18). After declining during the 1990s, U.S. suicide rates now roughly equal those of 100 years ago. In recent weeks, the surprising high-profile suicides of designer Kate Spade and chef and television star Anthony Bourdain have attracted more attention to this problem.
“The field of suicide research needs to move away from its obsession with long-term risk studies,” says psychologist David Klonsky of the University of British Columbia in Vancouver. A better understanding of how particular suicidal thoughts play out in daily life will lead to the identification of the most telling warning signs of impending suicide attempts, Klonsky predicts. Current theories focus on a range of potential factors that transform suicidal thoughts into life-ending actions, including feeling like a burden to others and suffering from unrelenting pain and hopelessness (SN: 1/9/16, p. 22).
Researchers can’t yet pinpoint suicide alarms for specific groups of people. That makes it even more vital for people contemplating suicide to contact suicide hotlines, psychotherapists and friends for help, Klonsky says. (To reach the National Suicide Prevention Lifeline, call 1-800-273-TALK (8255).)
The rise of real-time, digital monitoring holds promise for giving clinicians a heads-up as to who is in the most immediate danger of acting on suicidal thoughts. A handful of studies published since 2009 have found that thoughts of suicide often appear rapidly in individuals with past suicide attempts, and can vary dramatically from hour to hour.
A team led by psychologist Evan Kleiman of Harvard University has taken digital monitoring a step further. The researchers recruited 51 adults from online forums related to suicide and self-harm and 32 adults hospitalized at a Boston psychiatric facility for recent suicide attempts or severe suicidal thoughts. Volunteers carried smartphones that prompted them four times daily, between four and eight hours apart, to rate the intensity of their current desire to kill themselves, their intention to carry out the act and their ability to resist suicidal urges. Those in the online group provided responses for 28 consecutive days. Hospitalized participants provided responses until they were discharged, a period that typically lasted one to two weeks.
The same five patterns of suicidal thinking appeared in both groups, Kleiman’s team reports in a paper scheduled for publication later this year in Depression and Anxiety. One of those profiles may be associated with the greatest risk for trying to kill oneself in the future, the researchers say. Some individuals reported, on average, low levels of suicidal thoughts that either stayed constant, varied moderately or fluctuated greatly throughout the day. Others reported severe suicidal thoughts that varied either a little or a lot from one report to the next.
Among past-year attempters, suicide tries in the month before the study clustered among those reporting severe suicidal thoughts with few fluctuations. No such association appeared in the hospitalized group, probably because most of those with each profile had been admitted shortly after suicide attempts. Following these people for a longer period, after hospital discharge, might yield a link between a specific profile of suicidal thinking and previous or new suicide attempts.
Kleiman is now participating in a similar study, directed by Harvard psychologist Matthew Nock, of 300 adults and 300 adolescents with histories of suicide attempts who will be monitored for six months after discharge from psychiatric facilities. Participants will respond to smartphone questions and wear sensors that monitor sleep and activity cycles. “Some people have difficulty recognizing how distressed they are in the moment, so we need to capture distress with nonverbal measures,” Kleiman says. By identifying these individuals, clinicians could help them to recognize physical signs of distress in themselves and devise a plan to get help when such signs occur, Klonsky adds.
A related proposal holds that at least two forms of suicidal thinking, one related to spikes in distress, exist and demand closer study in smartphone studies. Psychiatrist Maria Oquendo of the University of Pennsylvania’s Perelman School of Medicine and colleagues suspect that the first consists of sudden bursts of suicidal thoughts following stressful experiences, possibly rooted in stress sensitivity due to child abuse or other early traumas. The second is linked to a consistently depressed mood that likely leads to carefully planned suicide attempts. Oquendo and her colleagues have found evidence for these two types of suicidal thinking in surveys of more than 6,700 U.S. college students.
Stress, or the lack of it, might play a role in some or all of the patterns of suicidal thinking identified by Kleiman’s group. Sleep and activity data in the team’s upcoming study may provide an indirect look at how stress affects suicidal thoughts.
Another digital-monitoring study in the works is that of psychologist Catherine Glenn of the University of Rochester in New York. She is currently assembling a smartphone-and-sensor study that will track 50 teenagers hospitalized following suicide attempts for one month after discharge. “It’s still unclear how much suicidal thoughts fluctuate over short periods of time, especially in youth,” Glenn says.
Despite its promise, digital monitoring of people at risk for suicide only works if people respond to repeated surveys. Consider that U.S. Army soldiers who refused to answer a survey question about the duration of their suicidal thoughts were especially likely to try later to kill themselves. A team led by Harvard psychologist Matthew Nock reported that finding in the February Journal of Abnormal Psychology. Rochester’s Glenn adds that some teens recently released from psychiatric facilities go offline for a couple of days before being hospitalized again for a suicide attempt.
“Suicide is such a complicated area of study,” Glenn says.
Time is out of joint on Venus. The planet’s thick air, which spins much faster than the solid globe, may push against the flanks of mountains and change Venus’ rotation rate.
Computer simulations show that the thick Venusian atmosphere, whipping around the planet at 100 meters per second, exerts enough push against a mountain on one side and suction on the other side to speed the planet’s rotation rate by about two minutes each Venus day, according to a study in Nature Geoscience June 18. That’s not much, considering that the planet rotates just once every 243 Earth days. By comparison, Venus’ atmosphere rotates about once every four Earth days. Precise measurements of the planet’s rotation rate have varied by about seven minutes, however. The push and pull of the air over the mountains could help explain the mismatch, with some other force — possibly the gravitational influence of the sun — slowing the planet’s spin back down. The simulations by UCLA planetary scientist Thomas Navarro and colleagues are the first to account for a 10,000-kilometer-long wave in Venus’ cloud tops , spotted in 2015 by the Japanese space agency’s Akatsuki spacecraft (SN: 2/18/17, p. 5) . Similar waves are launched into the atmosphere on Earth when air flows over a mountain, but they normally dissipate quickly as opposing winds break them up. Venus’ atmosphere rotates so much faster than the planet and in such a uniform direction that the waves could persist for a long time. “This work is very interesting,” says planetary scientist Tetsuya Fukuhara of Rikkyo University in Tokyo, one of the researchers who discovered the atmosphere wave. The work helps explain where the wave comes from and addresses how Venus’ surface features affect the atmosphere, “which is the most important issue in the Venus atmospheric science.”
More detailed measurements of Venus’ rotation, possibly taken with a future lander (SN: 3/3/18, p. 14), could eventually help reveal details of Venus’ interior, such as the size of its core.
“Venus is the closest thing to Earth that we know of,” Navarro says, and yet its hot, thick, toxic atmosphere makes it utterly alien. “We’d like to know what’s inside.”
MADISON, Wis. — Giving children with autism a healthier mix of gut bacteria as a way to improve behavioral symptoms continued to work even two years after treatment ended.
The finding may solidify the connection between tummy troubles and autism, and provide more evidence that the gut microbiome — the collection of bacteria and other microbes that live in the intestines — can influence behavior.
“It’s a long way from saying there’s a cure for autism,” says Michael Hylin, a neuroscientist at Southern Illinois University in Carbondale who was not involved in the work. “But I think it’s a promising approach. It’s one that’s worthwhile.”
Children with autism spectrum disorders often have gastrointestinal problems. In previous studies, environmental engineer Rosa Krajmalnik-Brown of Arizona State University in Tempe and colleagues discovered that children with autism had fewer types of bacteria living in their guts than typically developing children did. And many of the kids were missing Prevotella bacteria, which may help regulate immune system actions. The researchers wondered whether altering the children’s cocktail of gut microbes to get a more diverse and healthier mix might help fix both the digestive issues and the behavioral symptoms associated with autism. In a small study of 18 children and teenagers with autism, the scientists gave kids fecal transplants from healthy donors over eight weeks. During and two months after the treatment, the kids had fewer gastrointestinal problems, including diarrhea, constipation, abdominal pain and indigestion, than before the therapy. Autism symptoms, such as hyperactivity, repetitive actions and irritability, also improved and seemed to be getting even better at the end of the trial than immediately after treatment ended, the team reported last year in Microbiome. But no one knew whether the improvements would last.
Krajmalnik-Brown announced the results of a two-year, follow-up study July 10 at the Beneficial Microbes Conference. The children had kept many of the Prevotella and other beneficial bacteria gained during treatment. And the diversity of bacteria in the children’s guts was even greater two years later than it was two months after the therapy ended, Krajmalnik-Brown said.
Some of the children’s stomach troubles had worsened slightly. But on average, scores on a gastrointestinal-symptoms scale were still more than 60 percent better than before kids received the transplants. The real surprise was that the kids’ autism symptoms continued to lessen two years after the therapy ended. Still, the study was small. “Don’t try this at home,” Krajmalnik-Brown cautioned.
The children were ages 7 to 16 when the study started. Ideally, treatment would begin at younger ages, Krajmalnik-Brown said, but the researchers have not gotten approval to conduct the research in younger children.
Next, the scientists need to make sure that the improved behavioral symptoms are really due to fecal transplants. The team will put the idea to the test in a study of the therapy in adults with autism.
The definite detection of nonterrestrial neutrinos, whether from the sun or from beyond the solar system, will yield a far deeper understanding of stellar interiors and, therefore, of how today’s universe came to be. — Science News, July 20, 1968.
Update In May 1968, researchers reported that a particle detector in South Dakota spotted ghostly subatomic particles called neutrinos from the sun, but only about a third as many as theories predicted. The shortage vexed physicists for decades, until the 2001 discovery that many of the sun’s electron neutrinos — the only kind the South Dakota detector was designed to find — switch flavors on their way to Earth, becoming muon and tau neutrinos (SN: 6/23/01, p. 388). That switch accounted for the sun’s missing neutrinos. Detectors have also glimpsed neutrinos spawned by supernova 1987A (SN: 3/7/87, p. 148) and even a supermassive black hole (SN Online: 7/12/18).
Using tiny 2-D materials, researchers have built microscopic chemical sensors that can be sprayed in an aerosol mist. Spritzes of such minuscule electronic chips, described online July 23 in Nature Nanotechnology, could one day help monitor environmental pollution or diagnose diseases.
Each sensor comprises a polymer chip about 1 micrometer thick and 100 micrometers across (about as wide as a human hair) overlaid with a circuit made with atomically thin semiconducting materials (SN Online: 2/13/18). This superflat circuit includes a photodiode, which converts ambient light into electric current, and a chemical detector. This chemical detector is composed of a 2-D material that conducts electric current more easily if the material binds with a specific chemical in its environment. Researchers can choose from a vast menu of 2-D materials to fashion detectors that are sensitive to different chemicals, says study coauthor Volodymyr Koman, a chemical engineer at MIT (SN Online: 1/17/18). In lab experiments, Koman and colleagues created a sensor spray that detected toxic ammonia vapor inside a sealed section of piping, as well as a spray that ID’d soot particles sprinkled across a flat surface.
Right now, researchers can determine whether their sensors have come in contact with certain particles only after the fact — by collecting the chips and hooking them up to electrodes. These electrodes test how easily electric current flows through a chip’s chemical detector, which reveals whether it touched a particular chemical after it was sprayed. But future sensors could emit light signals when in contact with target particles, says study coauthor Michael Strano, a chemical engineer at MIT.
The team is also investigating ways to power the circuits without ambient light and to integrate multiple chemical detectors onto a single chip. The simpler, single-chemical detection systems tested so far are “only the beginning,” Koman says. “It’s very exciting,” says Kourosh Kalantar-Zadeh, an electrical and chemical engineer at the University of New South Wales in Sydney whose commentary on the study appears in the same issue of Nature Nanotechnology. Sprayable sensors could someday detect gas leaks, pollution from power plants, volatile organic compounds and other air and water contaminants (SN: 3/17/18, p. 12).
Being so tiny, the devices could also be injected into a person’s bloodstream to monitor its chemical composition for medical purposes — like a blood test that wouldn’t require drawing any blood, Kalantar-Zadeh says. Or chemical sensors could be taken as nasal spray or swallowed to track digestive health (SN Online: 1/8/18). Unlike silicon-based devices that might pose environmental or health hazards, the polymers and the minute amounts of 2-D materials used to make the new devices are expected to be more biofriendly, he says.
The American Academy of Pediatrics is cautioning parents and pediatricians to avoid exposing children to eight chemicals found in food and in plastic packaging. The chemicals may be especially harmful to kids due to their small size, says the report published July 23 in Pediatrics. Pregnant women should also avoid the chemicals. And lower-income families who eat a lot of prepackaged foods could be at greater risk for exposure.
The chemicals include nitrates and nitrites, often added to processed meats as a preservative, as well as bisphenol A, or BPA, which is used to make durable plastics and has been linked to cancer, obesity and cardiovascular disease (SN: 10/3/15, p. 12). Also listed are phthalates, which help make plastic flexible, and perfluoroalkyl chemicals, or PFCs, which are resistant to stains, grease and water. These and other compounds have also been associated with endocrine disruption, obesity and insulin resistance, when cells don’t respond properly to insulin leading to an overproduction of the hormone (SN Online: 2/9/12). Some of these chemicals may also have neurocognitive effects, such as increased hyperactivity in children, says study coauthor Sheela Sathyanarayana, a physician and epidemiologist at the University of Washington in Seattle.
Scientists are unable to test the effects of these chemicals directly in humans, so evidence shows only that there is correlation, not causation, between exposure and disease.
To avoid these chemicals, the report suggests that parents buy fresh or frozen produce and skip processed meats packaged in plastic or food in metal cans, which can be lined with BPA. People should also avoid putting plastic containers in the dishwasher or microwave, the team says, where heat can draw chemicals out of plastic.
The researchers say that they hope the report prompts more strict regulation of these additives. “All parents should be able to know what they are feeding their children,” Sathyanarayana says.
