(Press-News.org) The microbes living in people's guts are much less diverse than those in humans' closest relatives, the African apes, an apparently long evolutionary trend that appears to be speeding up in more modern societies, with possible implications for human health, according to a new study.
Based on an analysis of how humans and three lineages of ape diverged from common ancestors, researchers determined that within the lineage that gave rise to modern humans, microbial diversity changed slowly and steadily for millions of years, but that rate of change has accelerated lately in humans from some parts of the world.
People in nonindustrialized societies have gut microbiomes that are 60 percent different from those of chimpanzees. Meanwhile, those living in the U.S. have gut microbiomes that are 70 percent different from those of chimps.
"It took millions of years, since humans and chimpanzees split from a common ancestor, to become 60 percent different in these colonies living in our digestive systems," said Howard Ochman, professor of integrative biology at The University of Texas at Austin and co-author of the study. "On the other hand, in apparently only hundreds of years — and possibly a lot fewer — people in the United States lost a great deal of diversity in the bacteria living in their gut."
That rapid change might translate into negative health effects for Americans. Previous research has shown that compared with several populations, people living in the U.S. have the lowest diversity of gut microbes. Still other research has linked a lack of microbial diversity in human guts to various diseases such as asthma, colon cancer and autoimmune diseases.
The results of this latest study, carried out by researchers from The University of Texas at Austin, Yale University, the University of Pennsylvania and elsewhere, appear this week in the journal Proceedings of the National Academy of Sciences. The lead author is Andrew Moeller, a visiting scholar at The University of Texas at Austin and a graduate student at Yale University.
One possible explanation for humans evolving to have less diversity in their gut microbiomes is that they shifted to a diet with more meat and fewer plants. Plants require complex communities of microbes to break them down, which is not as true for meat.
As for why Americans have experienced much more rapid changes in microbial diversity compared with people in less industrialized societies, some experts have suggested more time spent indoors, increased use of antibacterial soaps and cleaners, widespread use of antibiotics and high numbers of births by Cesarean section all may play a role. Antibiotics and antimicrobial cleaners can kill good bacteria along with the bad, and C-section deliveries prevent babies from receiving certain bacteria from the mother typically conferred during vaginal births.
"Declining diversity in the gut has been a trend for a long time," said Ochman. "It's tantalizing to think that the decrease in microbial diversity in humans is due only to modern medical practices and other lifestyle changes, but this research shows other factors over time also must have played a role."
The researchers analyzed the genetic makeup of bacteria in fecal samples from humans, chimpanzees, bonobos and gorillas to draw their conclusions.
INFORMATION:
Moeller and Ochman's co-authors are Yingying Li at the University of Pennsylvania; Eitel Mpoudi-Ngole at the Institut de Recherches Médicales et d'Études des Plantes Médicinales, Prévention du Sida au Cameroun (Republic of Cameroon); Steve Ahuka-Mundeke at Institut National de Recherche Biomédicale (Democratic Republic of Congo) and the University of Montpellier (France); Elizabeth Lonsdorf at Franklin & Marshall College; Anne Pusey at Duke University; Martine Peeters at the University of Montpellier; and Beatrice Hahn at the University of Pennsylvania.
This work was supported by grants from the National Institutes of Health, the National Science Foundation, Agence Nationale de Recherche sur le Sida and the Jane Goodall Institute.
Download the paper "Rapid changes in the gut microbiome during human evolution" (PNAS, November 3,2014) at: http://www.pnas.org/content/early/2014/10/29/1419136111.full.pdf+html
Compared with apes, people's gut bacteria lack diversity, study finds
2014-11-04
[Attachments] See images for this press release:
ELSE PRESS RELEASES FROM THIS DATE:
Study recommends integrating housing data with health data to improve patient medical care
2014-11-03
A study to be released in the November issue of Health Affairs shows that integrating community housing data on such code violations as mold and cockroaches with health data can identify at-risk geographical areas of medical concern and help target patients for medical interventions.
Researchers from Cincinnati Children's Hospital Medical Center used geocoding, or mapping, to examine associations between housing code violations and children's health. They found that children hospitalized for asthma are nearly twice as likely to be rehospitalized or to revisit the emergency ...
Higher risk of bleeding in atrial fibrillation patients taking blood thinner dabigatran
2014-11-03
PITTSBURGH, Nov. 3, 2014 – Patients with atrial fibrillation who take the blood thinner dabigatran are at greater risk for major bleeding and gastrointestinal bleeding than those who take warfarin, according to a new study by researchers at the University of Pittsburgh Graduate School of Public Health.
The findings, based on Medicare claims data and published today in JAMA Internal Medicine, indicate greater caution is needed when prescribing dabigatran to certain high-risk patients.
Atrial fibrillation, an arrhythmia in which the heart's upper chambers irregularly ...
Dabigatran associated with higher incidence of major bleeding vs. warfarin
2014-11-03
A study of Medicare beneficiaries suggests the anticoagulant medication dabigatran should be prescribed with caution because it appears to be associated with a higher incidence of major bleeding and a higher risk of gastrointestinal bleeding but a lower risk of intracranial hemorrhage than warfarin, according to a report published online by JAMA Internal Medicine.
Dabigatran etexilate mesylate was approved by the U.S. Food and Drug Administration (FDA) in 2010 to prevent stroke and embolism (blood clots) in patients with nonvalvular atrial fibrillation (AF, abnormal heartbeat) ...
Increased prevalence in autism diagnoses linked to reporting in Denmark
2014-11-03
About 60 percent of the increase in the observed prevalence of autism spectrum disorders (ASDs) in Danish children appears to be largely due to changes in reporting practices, according to a study published online by JAMA Pediatrics.
The prevalence of ASDs (neurodevelopmental disorders characterized by impaired social interactions, communication and by repetitive behaviors) has increased over the past 30 years. The current estimate is about 1 percent of children, although it also has been reported to be higher, according to background information in the study. That increase ...
Telephone counseling leads more adult childhood cancer survivors to get heart screenings
2014-11-03
(MEMPHIS, Tenn. – November 3, 2014) Supplementing written heart screening guidelines with telephone counseling from specially trained nurses more than doubled the likelihood that adult survivors of childhood cancer received recommended heart checks, according to results from the Childhood Cancer Survivor Study (CCSS). St. Jude Children's Research Hospital investigators led the research, whose findings appear in the current issue of the Journal of Clinical Oncology.
The research focused on adults whose childhood cancer treatment put them at risk for a variety of ...
Migraine linked to defective 'insulation' around nerve fibers, suggests study in Plastic and Reconstructive Surgery
2014-11-03
November 3, 2014 – A new study shows cellular-level changes in nerve structure and function that may contribute to the development of migraine headaches, reports the November issue of Plastic and Reconstructive Surgery®, the official medical journal of the American Society of Plastic Surgeons (ASPS).
Nerve specimens from patients with migraine show abnormalities of the myelin sheath that serves as "insulation" around the nerve fibers," according to the study by ASPS Member Surgeon Bahman Guyuron, MD, of Case Western Reserve University, Cleveland. The findings ...
Comprehensive breast center improves quality of care for breast reconstruction
2014-11-03
November 3, 2014 – After opening a comprehensive breast center (CBC), one hospital achieved significant improvement in key measures of quality of care for women undergoing breast reconstruction, reports the November issue of Plastic and Reconstructive Surgery®, the official medical journal of the American Society of Plastic Surgeons (ASPS).
Centralized breast cancer care at CBCs can lead to more timely breast reconstruction for women undergoing breast cancer surgery, suggests the study by ASPS Member Surgeon Albert H. Chao, MD, and colleagues of The Ohio State ...
UCLA astronomers solve puzzle about bizarre object at the center of our galaxy
2014-11-03
For years, astronomers have been puzzled by a bizarre object in the center of the Milky Way that was believed to be a hydrogen gas cloud headed toward our galaxy's enormous black hole.
Having studied it during its closest approach to the black hole this summer, UCLA astronomers believe that they have solved the riddle of the object widely known as G2.
A team led by Andrea Ghez, professor of physics and astronomy in the UCLA College, determined that G2 is most likely a pair of binary stars that had been orbiting the black hole in tandem and merged together into an extremely ...
Forests lose essential nitrogen in surprising way, find scientists
2014-11-03
ITHACA, N.Y. – Even during summer dry spells, some patches of soil in forested watersheds remain waterlogged. Researchers have discovered that these patches act as hot spots of microbial activity that remove nitrogen from groundwater and return it to the atmosphere, as reported in a Nov. 3 article in Proceedings of the National Academy of Sciences.
Nitrogen is a critically important nutrient for plant growth in the forest. Denitrification removes this nutrient from the ecosystem and can reduce the growth and productivity of the forest.
The research contributes ...
New way to make batteries safer
2014-11-03
CAMBRIDGE, MA -- Every year, nearly 4,000 children go to emergency rooms after swallowing button batteries — the flat, round batteries that power toys, hearing aids, calculators, and many other devices. Ingesting these batteries has severe consequences, including burns that permanently damage the esophagus, tears in the digestive tract, and in some cases, even death.
To help prevent such injuries, researchers at MIT, Brigham and Women's Hospital, and Massachusetts General Hospital have devised a new way to coat batteries with a special material that prevents them ...