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Obesity genetics
October 16, 2007Genetic variation implicated in Pima obesity
New evidence that genetics plays a key role in obesity is published today in the International Journal of Bioinformatics Research and Applications. The findings relate to the genetics of modern Pima Indians who have an unusually high rate of obesity but could be extrapolated to all people. Their obesity is thought to be linked to a thrifty metabolism that allowed them to metabolize food more efficiently in times when little was available but causes problems when food is in abundance.
Mark Rowe, David McClellan, and colleagues at Brigham Young University in Provo, Utah, USA, have studied the effect of evolutionary selection on Pima Indians, a people indigenous to the present-day Sonora desert of Arizona and New Mexico. The researchers anticipated an effect consistent with higher metabolic efficiency among these people and focused specifically on recently discovered variations in their mitochondrial DNA, so-called SNPs, or single nucleotide polymorphisms.
The metabolic rates of 200 obese Pima individuals were measured and revealed that two of the three known SNPs influence metabolic efficiency. The researchers then used the genetics software TreeSAAP, to analyze the biochemical changes caused by these SNPs and then tracked the evolutionary selection of these genetic variations in 107 different types of mammals. This allowed them to propose a mechanism by which these SNPs affect the mitochondrial respiratory chain and consequently increase metabolic efficiency in the Pima people.
The team suggests that an increased metabolic efficiency could have been an evolutionary advantage. The SNPs may have persisted because they helped the Pima survive the harsh dietary environment of the Sonora desert throughout the history of the people. In the current environment of caloric over-consumption an increased efficiency is unfavorable and may contribute to the high rates of obesity among the Pimas.
While the Pima Indians are an extreme case, the entire human population may also have evolved in a restricted caloric environment, say the researchers. Many populations may exhibit similar SNPs that were advantageous to our ancestors but may now be detrimental. The presence of these SNPs may thus provide one explanation as to why obesity is so rife in the 21st century.
Inderscience Publishers
The metabolic rates of 200 obese Pima individuals were measured and revealed that two of the three known SNPs influence metabolic efficiency. The researchers then used the genetics software TreeSAAP, to analyze the biochemical changes caused by these SNPs and then tracked the evolutionary selection of these genetic variations in 107 different types of mammals. This allowed them to propose a mechanism by which these SNPs affect the mitochondrial respiratory chain and consequently increase metabolic efficiency in the Pima people.
The team suggests that an increased metabolic efficiency could have been an evolutionary advantage. The SNPs may have persisted because they helped the Pima survive the harsh dietary environment of the Sonora desert throughout the history of the people. In the current environment of caloric over-consumption an increased efficiency is unfavorable and may contribute to the high rates of obesity among the Pimas.
While the Pima Indians are an extreme case, the entire human population may also have evolved in a restricted caloric environment, say the researchers. Many populations may exhibit similar SNPs that were advantageous to our ancestors but may now be detrimental. The presence of these SNPs may thus provide one explanation as to why obesity is so rife in the 21st century.
Inderscience Publishers
Obesity Current Events and Obesity News RSSResearchers: Ban on fast food TV advertising would reverse childhood obesity trends
A ban on fast food advertisements in the United States could reduce the number of overweight children by as much as 18 percent, according to a new study being published this month in the Journal of Law and Economics.
Antibiotics Can Cause Pervasive, Persistent Changes to the Microbial Community in the Human Gut, MBL and Stanford Scientists Report
Using a novel technique developed by Mitchell Sogin of the Marine Biological Laboratory (MBL) to identify different types of bacteria, scientists have completed the most precise survey to date of how microbial communities in the human gut respond to antibiotic treatment.
Physical activity after bariatric surgery improves weight loss, quality of life
A new study by researchers from The Miriam Hospital's Centers for Behavioral and Preventive Medicine suggests increased physical activity after bariatric surgery can yield better postoperative outcomes.
Vitamin C lowers levels of heart disease biomarker, finds study, adds to debate of health benefits
A new study led by researchers at the University of California, Berkeley, adds to the evidence that vitamin C supplements can lower concentrations of C-reactive protein (CRP), a central biomarker of inflammation that has been shown to be a powerful predictor of heart disease and diabetes.
Fatty diet during pregnancy makes new cells in fetal brain that cause early onset obesity
A study in rats shows that exposure to a high-fat diet during pregnancy produces permanent changes in the offspring's brain that lead to overeating and obesity early in life, according to new research by Rockefeller University scientists.
Study shows direct link between leptin and obesity-related cardiovascular disease
Obese people who don't have high cholesterol or diabetes might think they're healthy - despite the extra pounds.
Eye conditions linked with obstructive sleep apnea
If a good night's sleep helps the brain and body perform better, it's a good guess that sleep problems can cause more than just fatigue. Numerous studies have shown a connection between sleep disorders and medical conditions such as cardiovascular disease, cerebrovascular disease, and metabolic disorders, including the risk of obesity and diabetes mellitus. In the November issue of Mayo Clinic Proceedings, Mayo Clinic researchers outline several interesting associations between sleep disorders and eye disease.
Sleep Apnea May Be Risk Factor for Sudden Cardiac Death, Mayo Clinic Research Concludes
After studying the sleep characteristics of nearly 11,000 adults in an overnight sleep laboratory, Mayo Clinic researchers suggest that obstructive sleep apnea (OSA) - and, in particular, the low nighttime oxygen saturation of the blood it causes - may be a risk factor for sudden cardiac death (SCD).
Eliminating soda from school diets does not affect overall consumption
With childhood obesity increasing, school administrators and public health officials are reducing availability of sugar-sweetened beverages (SSB) in schools.
Pregnancy diabetes doubles the risk of language delay in children
Children born to mothers with pregnancy-related diabetes run twice the risk of language development problems, according to a research team directed by Professor Ginette Dionne of Université Laval's School of Psychology. Details of this discovery are published in the most recent issue of the scientific journal Pediatrics.
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