Scientists have presented the most conclusive evidence yet that genes play a significant role in parenting.A study by two Michigan State University psychologists refutes the popular theory that how adults parent their children is strictly a function of the way they were themselves parented when they were children.While environmental factors do play a role in parenting, so do a person’s genes, said S. Alexandra Burt, associate professor of psychology and co-author of a study led by doctoral student Ashlea M. Klahr.”The way we parent is not solely a function of the way we were parented as children,” Burt said. “There also appears to be genetic influences on parenting.”Klahr and Burt conducted a statistical analysis of 56 scientific studies from around the world on the origins of parenting behavior, including some of their own. The comprehensive analysis, involving more than 20,000 families from Australia to Japan to the United States, found that genetic influences in the parents account for 23 percent to 40 percent of parental warmth, control and negativity towards their children.”What’s still not clear, however, is whether genes directly influence parenting or do so indirectly, through parent personality for example,” Klahr said.The study sheds light on another misconception: that parenting is solely a top-down process from parent to child. While parents certainly seem to shape child behavior, parenting also is influenced by the child’s behavior — in other words, parenting is both a cause and a consequence of child behavior.”One of the most consistent and striking findings to emerge from this study was the important role that children’s characteristics play in shaping all aspects of parenting,” the authors write.Ultimately, parenting styles stem from many factors.”Parents have their own experiences when they were children, their own personalities, their own genes. On top of that, they are also responding to their child’s behaviors and stage of development,” Burt said. “Basically, there are a lot of influences happening simultaneously. Long story short, though, we need to be sensitive to the fact that this is a two-way process between parent and child that is both environmental and genetic.”The study is published in Psychological Bulletin, a research journal of the American Psychological Association.Story Source:The above story is based on materials provided by Michigan State University. Note: Materials may be edited for content and length.Read more
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A University of Rhode Island anthropologist, along with colleagues from an international team of scientists, has discovered definitive evidence of the environment inhabited by the early ape Proconsul on Rusinga Island, Kenya. The findings provide new insights into understanding and interpreting the connection between habitat preferences and the early diversification of the ape-human lineage.Their research, which was published today in the journal Nature Communications, demonstrates that Proconsul and its primate relative Dendropithecus inhabited “a widespread, dense, multistoried, closed canopy” forest.Holly Dunsworth, URI assistant professor of anthropology, said that the research team found fossils of a single individual of Proconsul, which lived 18 to 20 million years ago, among geological deposits that also contained tree stump casts, calcified roots and fossil leaves. The discovery underscores the importance of forested environments in the evolution of early apes.”To have the vegetation of a habitat preserved right along with the fossil primates themselves isn’t a regular occurrence in primate paleontology,” she said. “It’s especially rare to have so many exquisite plant fossils preserved at ancient ape sites.”Rusinga has been known since the 1980s for preserving a fossil ape and other creatures in a hollowed out, fossilized tree trunk. But it wasn’t until the research team’s discovery of additional tree trunks and fossil primates preserved in the same ancient soil that there was a strong link between the ape and its habitat at the site.”It’s probably the best evidence linking ape to habitat that we could ask for,” Dunsworth said. “Combined with analyses of the roots, trunks and even beautifully preserved fossil leaves, it’s possible to say that the forest was a closed canopy one, meaning the arboreal animals, like Proconsul, could easily move from tree-to-tree without coming to the ground. This environmental evidence jibes with our behavioral interpretations of Proconsul anatomy–as being adapted for a life of climbing in the trees–and with present-day monkey and ape ecology.”Additional evidence from the excavation site has shown that the landscape was stable for many years while the forest grew.According to co-author Daniel Peppe of Baylor University, evidence from the forest soil suggests “the precipitation was seasonal with a distinct wet and dry period. During the dry season, there was probably relatively little rainfall,” he said. “Additionally, by studying fossil leaves at the site, we were able to estimate that there was about 55 to 100 inches of rainfall a year and the average annual temperature was between 73 and 94 degrees Fahrenheit.”Research on Rusinga Island has been ongoing for more than 80 years and has resulted in the collection of thousands of mammal fossils, including many well-preserved specimens of Proconsul and other primates. Evidence from these fossils indicate that Proconsul probably had a body position somewhat similar to modern monkeys, but that details of its anatomy suggest some more ape-like climbing and clambering abilities. …Read more
New research from the University of Adelaide has delved into the reasons why some people are unable to break free of their delusions, despite overwhelming evidence explaining the delusion isn’t real.In a new paper published in the journal Frontiers in Psychology, University of Adelaide philosopher Professor Philip Gerrans says dreams and delusions have a common link — they are associated with faulty “reality testing” in the brain’s higher order cognitive systems.”Normally this ‘reality testing’ in the brain monitors a ‘story telling’ system which generates a narrative of people’s experience,” Professor Gerrans says.”A simple example of normal reality testing is the person who gets a headache, immediately thinks they might have a brain tumor, then dismisses that thought and moves on. Their story episode ‘I might have brain cancer’ gets tested and quickly rejected.”In someone who has problems with reality testing, that story might persist and may even be elaborated and translated into action. Such people can experience immense mental health difficulties, even to the point of becoming a threat to themselves or to others,” he says.In his paper, Professor Gerrans discusses delusions triggered by feelings of familiarity and unfamiliarity, such as the “Capgras delusion” — the delusion of “doubles.” One example is of a man who, after serious head injury following a motor vehicle accident, returned home from the hospital after a year only to state repeatedly that his family had been replaced by impostors.”His family looked familiar but didn’t feel familiar, and the story in his head made sense of that feeling. It didn’t matter how much people tried to point out that his family was the same, in his mind they had been completely replaced by impostors,” Professor Gerrans says.He says in the “Fregoli delusion,” people think they’re being followed by a familiar person in disguise as a way of coping with a feeling of familiarity evoked by seeing a stranger.”People also experience feelings of familiarity and unfamiliarity in dj vu — a sense that a new place is strangely familiar, and the reverse, jamais vu — a sense of extreme unfamiliarity evoked by a familiar place. However, such feelings do not lead to delusion in people whose reality testing is intact.”Professor Gerrans says better understanding this reality testing system could help to improve outcomes for people living with such difficulties.”Trying to treat someone experiencing these delusions by telling them the truth is not necessarily going to help, so new strategies need to be developed to assist them. Ultimately, that’s the aim of this work — to help explain the nature of reality testing in order to help people find a way of working through or around their delusions so that the delusions no longer adversely affect their lives.”Professor Gerrans’s new book, The Measure of Madness. Philosophy and Cognitive Neuropsychiatry (MIT Press), will be published this year.What’s the difference between a dream, a delusion and an hallucination? Professor Gerrans explains:Dream: The images, sensations and thoughts we experience during sleep. In dreams we simply have experiences, we don’t have beliefs about experience because “reality testing” systems are not active.Delusion: An irrational belief at odds with reality maintained in the face of obvious contrary evidence and logical argument.Hallucination: The apparent perception of an object not actually present.Dj vu: The feeling that you have previously experienced a situation which is in fact unfamiliar. Caused by an erroneous “sense of familiarity.”Jamais vu: The feeling that a familiar situation has not been experienced before. …Read more
New research is lighting up yet another reason for women to quit smoking. In a study published online in the journal Menopause, researchers from the Perelman School of Medicine at the University of Pennsylvania report the first evidence showing that smoking causes earlier signs of menopause — in the case of heavy smokers, up to nine years earlier than average — in white women with certain genetic variations.Though previous studies have shown that smoking hastens menopause by approximately one to two years regardless of race or genetic background, this study is the first of its kind to demonstrate that genetic background is significantly associated with a further increased risk of menopause in some white women who smoke. No statistically significant relationships between smoking, the gene variants under investigation and earlier menopause were observed in African American women.While symptoms of menopause — such as hot flashes, anxiety and insomnia — can result in discomfort, embarrassment, and irritability, the onset of menopause is also associated with risks of coronary artery disease, osteoporosis, and death from all causes. On average, women enter menopause at around 50 years of age. However, the research team now reports that menopause may begin at an earlier age in white female smokers who are carriers of two different gene variants. While the genes themselves do not result in early onset menopause, variations of the genes — CYP3A4*1B and CYP1B1*3 — were found to increase the risk of entering menopause at an earlier age in white smokers. The genetic variants were present in seven and 62 percent of white women in the study population, respectively.”This study could shed new light on how we think about the reproductive risks of smoking in women. We already know that smoking causes early menopause in women of all races, but these new results show that if you are a white smoker with these specific genetic variants, your risk of entering menopause at any given time increases dramatically,” said the study’s lead author Samantha F. Butts, MD, MSCE, assistant professor of Obstetrics and Gynecology at Penn Medicine.Results of the study, which enrolled over 400 women aged 35 to 47 from the Penn Ovarian Aging Study, found that in carriers of the CYP3A4*1B variation, the average time-to-menopause after entering the study in heavy smokers, light smokers, and nonsmokers was 5.09 years, 11.36 years, and 13.91 years, respectively. This means that for heavily smoking white females with this genetic background, the average time-to-menopause was approximately nine years earlier than in nonsmoking carriers.In white carriers of the CYP1B1*3 variation, the average time-to-menopause in heavy smokers, light smokers, and nonsmokers was 10.41 years, 10.42 years, and 11.08 years, respectively — a statistically significant difference although not as stark as the findings for the CYP3A4*1B variant.The Penn study did not examine why no statistically significant relationships between smoking, the gene variants under investigation, and earlier menopause were observed in African Americans.”It is possible that uniform relationships among white and African American women were not found due to other factors associated with race that modify the interaction between smoking and genes,” said Butts. …Read more
Commercial citrus growers are often challenged by environmental conditions in winter, including low seasonal rainfall that is typical in many citrus growing regions. Growers must rely on irrigation to sustain citrus crops through dry winters, so understanding how to determine citrus irrigation needs is critical for successful operations.Authors of a study published in HortScience noted that current methods used to determine moisture needs for citrus are limited, in that they do not account for effects of cold acclimation on water requirements. “Evidence suggests that at least some changes in plant water deficits occur as a result of cold temperatures and not dry soil,” noted Robert Ebel, lead author of the study. “Changes in citrus water relations during cold acclimation and independent of soil moisture content are not well understood. Our study was conducted to characterize changes in plant relations of citrus plants with soil moisture carefully maintained at high levels to minimize drought stress.”Ebel and his colleagues conducted two experiments–the first in Immokalee, Florida, using potted sweet orange, and the second in Auburn, Alabama, using Satsuma mandarin trees. The citrus plants were exposed to progressively lower, non-freezing temperatures for 9 weeks. During the experiments trees were watered twice daily–three times on the days data were collected–to minimize drought stress.Results of the experiments showed that soil moisture was higher for plants in the cold compared to plants in the warm chamber, and results showed that cold temperatures promoted stomatal closure, higher root resistance, lower stem water potential, lower transpiration, and lower stem water potential. Leaf relative water content was not different for cold-acclimated trees compared with the control trees. The key to minimizing drought stress, the scientists found, was carefully maintaining high soil moisture contents throughout the experiments, especially on the days that the measurements were performed.”Our modern understanding of plant water relations has mainly evolved from studying growing plants at warm temperatures and in soils of varying moisture contents,” Ebel explained. “However, this study demonstrates that those relationships are not consistent for citrus trees exposed to cold-acclimating temperatures.”The authors added that the study findings could have implications for commercial citrus growers who currently use traditional measures of determining irrigation scheduling during winter months.The complete study and abstract are available on the ASHS HortScience electronic journal web site: http://hortsci.ashspublications.org/content/48/10/1309.abstractStory Source:The above story is based on materials provided by American Society for Horticultural Science. …Read more
Oct. 16, 2013 — Early childhood education can yield short- and long-term educational, economic, and societal benefits, underscoring the value of expanding publicly funded preschool education, New York University Professor Hirokazu Yoshikawa outlines in a research brief released today.”Investing in Our Future: The Evidence Base on Preschool Education,” authored by Yoshikawa, a professor NYU’s Steinhardt School of Culture, Education, and Human Development, and other early childhood experts, reviews existing scholarship on why early skills matter, which children benefit from preschool, the short- and long-term effects of preschool programs on children’s school readiness and life outcomes, the importance of program quality, and the costs versus benefits of preschool education.The findings, which offer a roadmap for broad, quality implementation of preschool programs, expand upon studies that have long served as barometers for the value of early childhood education: the Abecedarian Project, which traces back to the 1970s, and the Perry Preschool Project, which commenced in the 1960s.”Scientific evidence on the impacts of early childhood education has progressed well beyond exclusive reliance on the evaluations of the Perry Preschool and Abecedarian programs,” says Yoshikawa, the Courtney Sale Ross University Professor in NYU Steinhardt’s Department of Applied Psychology and lead author of the brief. “More recent evidence tells us a great deal about what works in early education and how early education might be improved. The combination of evidence-based curricula and in-classroom coaching is particularly promising and has been implemented at scale with large positive effects on children.””The recent evidence includes evaluations of city-wide public preschool programs such as those in Tulsa and Boston,” according to Deborah Phillips, professor of psychology at Georgetown University and a co-author of the brief. “Evaluations of these programs tell us that preschool programs implemented at scale can be high quality, can benefit children from a range of socioeconomic backgrounds, and can reduce disparities.”The evaluation of the Boston preschool program was conducted by Yoshikawa and Christina Weiland of the University of Michigan and was recently published in the journal Child Development.The research brief was funded by the Foundation for Child Development and produced in collaboration with the Society for Research in Child Development.According to the authors, the current science and evidence base on early childhood education shows that:• Large-scale public preschool programs that are of high quality can have a substantial impact on children’s early learning. For example, preschool systems in Tulsa and Boston have produced gains of between half and a full year of additional learning in reading and math.• Quality preschool education is a profitable investment. Cost-benefit estimates based on older, intensive interventions, such as the Perry Preschool Program, as well as contemporary, large-scale public preschool programs, such as the Chicago Child-Parent Centers and Tulsa’s preschool program, range from three to seven dollars saved (e.g., higher earnings) for participants for every dollar spent.• Quality preschool education can benefit middle-class children as well as disadvantaged children. The evidence is clear that middle-class children can benefit substantially and that benefits outweigh the costs for children from middle-income as well as those from low-income families. However, children from low-income families benefit more and therefore universal preschool can reduce disparities in skills at school entry.• Long-term benefits occur despite convergence of test scores. As children from low-income families in preschool evaluation studies are followed into elementary school, differences between those who participated in preschool and those who did not on tests of academic achievement are reduced. …Read more
Aug. 30, 2013 — An international team of researchers presents fresh evidence that confirms the existence of the superheavy chemical element 115. The experiment was conducted at the GSI Helmholtz Center for Heavy Ion Research, an accelerator laboratory located in Darmstadt. Under the lead of physicists from Lund University in Sweden, the group, which included researchers from Johannes Gutenberg University Mainz (JGU) and the Helmholtz Institute Mainz (HIM), was able to present a way to directly identify new superheavy elements.Share This:Elements beyond atomic number 104 are referred to as superheavy elements. They are produced at accelerator laboratories and generally decay after a short time. Initial reports about the discovery of an element with atomic number 115 were released from a research center in Russia in 2004. The then presented indirect evidence for the new element, however, was insufficient for an official discovery.For the new experiment, scientists at the Institute of Nuclear Chemistry at Mainz University took a sample of the exotic element americium. They deposited an americium layer on a thin foil, which was subsequently bombarded with calcium ions at the GSI facility. For the first time, the exploitation of a new detector system allowed registering photons along with the alpha-decay of the new element and its daughter products. Measured photon energies correspond to those expected for X-rays from these products and thus serve as the element’s fingerprint.”This can be regarded as one of the most important experiments in the field in recent years, because at last it is clear that even the heaviest elements’ fingerprints can be taken”, agreed Professor Dirk Rudolph from Lund University in Sweden and Professor Christoph Düllmann, professor at Mainz University and leading scientist at GSI Darmstadt and HIM. …Read more
Aug. 28, 2013 — For the first time, astronomers have seen the image of a distant quasar split into multiple images by the effects of a cloud of ionized gas in our own Milky Way Galaxy. Such events were predicted as early as 1970, but the first evidence for one now has come from the National Science Foundation’s Very Long Baseline Array (VLBA) radio telescope system.The scientists observed the quasar 2023+335, nearly 3 billion light-years from Earth, as part of a long-term study of ongoing changes in some 300 quasars. When they examined a series of images of 2023+335, they noted dramatic differences. The differences, they said, are caused by the radio waves from the quasar being bent as they pass through the Milky Way gas cloud, which moved through our line of sight to the quasar.”This event, obviously rare, gives us a new way to learn some of the properties of the turbulent gas that makes up a significant part of our Galaxy,” said Matt Lister, of Purdue University.The scientists added 2023+335 to their list of observing targets in 2008. Their targets are quasars and other galaxies with supermassive black holes at their cores. The gravitational energy of the black holes powers “jets” of material propelled to nearly the speed of light. The quasar 2023+335 initially showed a typical structure for such an object, with a bright core and a jet. In 2009, however, the object’s appearance changed significantly, showing what looked like a line of bright, new radio-emitting spots.”We’ve never seen this type of behavior before, either among the hundreds of quasars in our own observing program or among those observed in other studies,” Lister said.The multiple-imaging event came as other telescopes detected variations in the radio brightness of the quasar, caused, the astronomers said, by scattering of the waves.The scientists’ analysis indicates that the quasar’s radio waves were bent by a turbulent cloud of charged gas nearly 5,000 light-years from Earth in the direction of the constellation Cygnus. The cloud’s size is roughly comparable to the distance between the Sun and Mercury, and the cloud is moving through space at about 56 kilometers per second.Monitoring of 2023+335 over time may yield more such events, the scientists said, allowing them to learn additional details both about the process by which the waves are scattered and about the gas that does the scattering. …Read more
July 18, 2013 — You are not just yourself. You are also the thousands of microbes that you carry. In fact, they represent an invisible majority that may be more you than you realize.These microscopic fellow travelers are collectively called the microbiome. Realization that every species of plant and animal is accompanied by a distinctive microbiome is old news. But evidence of the impact that these microbes have on their hosts continues to grow rapidly in areas ranging from brain development to digestion to defense against infection to producing bodily odors.Now, contrary to current scientific understanding, it also appears that our microbial companions play an important role in evolution. A new study, published online on July 18 by the journal Science, has provided direct evidence that these microbes can contribute to the origin of new species by reducing the viability of hybrids produced between males and females of different species.This study provides the strongest evidence to date for the controversial hologenomic theory of evolution, which proposes that the object of Darwin’s natural selection is not just the individual organism as he proposed, but the organism plus its associated microbial community. (The hologenome encompasses the genome of the host and the genomes of its microscopic symbiotes.)”It was a high-risk proposition. The expectation in the field was that the origin of species is principally driven by genetic changes in the nucleus. Our study demonstrates that both the nuclear genome and the microbiome must be considered in a unified framework of speciation,” said Associate Professor of Biological Sciences Seth Bordenstein who performed the study with post-doctoral fellow Robert Brucker.They conducted their research using three species of the jewel wasp Nasonia. These tiny, match-head sized wasps parasitize blowflies and other pest flies, which make them useful for biological control.”The wasps have a microbiome of 96 different groups of microorganisms,” said Brucker. …Read more
June 17, 2013 — Systems such as a beating heart or a power grid that depend on the synchronized movement of their parts could fall prey to an invisible and chaotic tug-of-war known as a “chimera.” Sharing its name with the fire-breathing, zoologically patchy creature of Greek mythology, a chimera state arises among identical, rhythmically moving components — known as oscillators — when a few of those parts spontaneously fall out of sync while the rest remain synchronized.Whether chimera states exist in the real world has remained an imminent question since their discovery in theoretical studies 10 years ago. Now, researchers from Princeton University and Germany’s Max Planck Institute for Dynamics and Self-Organization (MPIDS) report the first purely physical experimental evidence that chimera states can occur naturally and under a broad range of circumstances.They report in the journal Proceedings of the National Academy of Sciences that a surprisingly simple experiment demonstrated that chimera states naturally lay at the crossroads of two types of synchronized motion — in-phase and antiphase. Imagine two groups of pendulums that swing in the same direction at the same time — that’s in-phase. Under antiphase, the pendulums move at the same pace, but one group goes left as the other goes right.Furthermore, the researchers found through mathematical models that the phenomenon can strike any process that relies on self-emergent synchronization, or the natural tendency of components to fall into the same rhythm. A range of things that swing, blink or pulsate share this quality, including clock pendulums, lightning bugs and heart cells.Researchers from Princeton University and Germany’s Max Planck Institute for Dynamics and Self-Organization report the first purely physical experimental evidence that chimera states can occur naturally within any process that relies on spontaneous synchronization, including clock pendulums, lightning bugs and heart valves. A chimera state arises among identical, rhythmically moving components when a few of those parts spontaneously fall out of sync while the rest remain synchronized. The researchers developed a simple apparatus made of two swings, each fitted with 15 metronomes (above). A spring connected the swings so that they moved together. When the swings were set in motion, the metronomes would eventually move together. Yet if the connecting spring was at a certain tensity, the symmetry spontaneously broke so that the metronomes on one swing stayed in lockstep (left) while the metronomes on the other swing moved erratically (right) despite the metronomes all being set to move at the same pace. …Read more
June 6, 2013 — A study using brain images from “quiet” MRI machines adds to the growing body of evidence that breastfeeding improves brain development in infants. Breastfeeding alone produced better brain development than a combination of breastfeeding and formula, which produced better development than formula alone.A new study by researchers from Brown University finds more evidence that breastfeeding is good for babies’ brains.The study made use of specialized, baby-friendly magnetic resonance imaging (MRI) to look at the brain growth in a sample of children under the age of 4. The research found that by age 2, babies who had been breastfed exclusively for at least three months had enhanced development in key parts of the brain compared to children who were fed formula exclusively or who were fed a combination of formula and breastmilk. The extra growth was most pronounced in parts of the brain associated with language, emotional function, and cognition, the research showed.This isn’t the first study to suggest that breastfeeding aids babies’ brain development. Behavioral studies have previously associated breastfeeding with better cognitive outcomes in older adolescents and adults. But this is the first imaging study that looked for differences associated with breastfeeding in the brains of very young and healthy children, said Sean Deoni, assistant professor of engineering at Brown and the study’s lead author.”We wanted to see how early these changes in brain development actually occur,” Deoni said. “We show that they’re there almost right off the bat.”The findings are in press in the journal NeuroImage and available now online.Deoni leads Brown’s Advanced Baby Imaging Lab. He and his colleagues use quiet MRI machines that image babies’ brains as they sleep. The MRI technique Deoni has developed looks at the microstructure of the brain’s white matter, the tissue that contains long nerve fibers and helps different parts of the brain communicate with each other. Specifically, the technique looks for amounts of myelin, the fatty material that insulates nerve fibers and speeds electrical signals as they zip around the brain.Deoni and his team looked at 133 babies ranging in ages from 10 months to four years. …Read more
May 31, 2013 — A major question in ecology has centered on the role of microbes in regulating ecosystem function. Now, in research published ahead of print in the journal Applied and Environmental Microbiology, Brajesh Singh of the University of Western Sydney, Australia, and collaborators show how changes in the populations of methanotrophic bacteria can have consequences for methane mitigation at ecosystem levels.”Ecological theories developed for macro-ecology can explain the microbial regulation of the methane cycle,” says Singh.In the study, as grasslands, bogs, and moors became forested, a group of type II methanotrophic bacterium, known as USC alpha, became dominant on all three land use types, replacing other methanotrophic microbes, and oxidizing, thus mitigating methane, a powerful greenhouse gas, explains Singh. “The change happened because we changed the niches of the microbial community.”The pre-eminence of USC alpha bacteria in this process demonstrates that the so-called “selection hypothesis” from macro-ecology “explains the changes the investigators saw in the soil functions of their land-use types,” says Singh. The selection hypothesis states that a small number of key species, rather than all species present determine key functions in ecosystems. “This knowledge could provide the basis for incorporation of microbial data into predictive models, as has been done for plant communities,” he says.”Evidence of microbial regulation of the biogeochemical cycle provides the basis for including microbial data in predictive models studying the effects of global changes,” says Singh.Singh warns that one should not take the results to mean that biodiversity is not important. Without microbial biodiversity, the raw materials — different microbial species with different capabilities — for adapting to changes in the environment would be unavailable, he says.Read more
Apr. 29, 2013 — Evidence has shown that green tea extract may be an effective herbal remedy useful for weight control and helping to regulate glucose in type 2 diabetes. In order to ascertain whether green tea truly has this potential, Jae-Hyung Park and his colleagues from the Keimyung University School of Medicine in the Republic of Korea conducted a study, now published in the Springer journal Naunyn-Schmedeberg’s Archives of Pharmacology.
The active constituents of green tea, which have been shown to inhibit intestinal glucose and lipid uptake, are a certain type of flavonoid called gallated catechins. The authors had previously suggested that the amount of gallated catechins necessary to reduce blood glucose concentrations can be achieved from a daily dose of green tea. However, the amount of green tea needed to decrease lipid uptake from the gut is higher and has been shown to have adverse effects in humans. Once in the bloodstream, gallated catechins can actually increase insulin resistance, which is a negative consequence especially in obese and diabetic patients.
For their study, the researchers tested the effects of green tea extract on body weight and glucose intolerance in both diabetic mice and normal mice fed a high-fat diet. To prevent a high dose of gallated catechins from reaching the bloodstream, the authors also used a non-toxic resin, polyethylene glycol, to bind the gallated catechins in the gut to prevent their absorption. They then looked at the effects on the mice of eating green tea extract alone, and eating green tea extract plus polyethylene glycol. They compared these against the effects of two other therapeutic drugs routinely prescribed for type 2 diabetes.
Results showed that green tea extract in isolation did not give any improvements in body weight and glucose intolerance. However, when green tea extract was given with polyethylene glycol, there was a significant reduction in body weight gain, insulin resistance and glucose intolerance in both normal mice on a high fat diet and diabetic mice. The polyethylene glycol had the effect of prolonging the amount of time the gallated catechins remained in the intestines, thereby limiting glucose absorption for a longer period.
Interestingly, the effects of the green tea extract in both the intestines and in the circulation were measurable at doses which could be achieved by drinking green tea on a daily basis. In addition, the effects of green tea extract were comparable to those found when taking two of the drugs which are currently recommended for non-insulin dependent diabetes.
The authors conclude that “dietary green tea extract and polyethylene glycol alleviated body weight gain and insulin resistance in diabetic and high-fat mice, thus ameliorating glucose intolerance. Therefore the green tea extract and polyethylene glycol complex may be a preventative and therapeutic tool for obesity and obesity-related type 2 diabetes without too much concern about side effects.”Read more