Starving orangutans might help to better understand obesity and eating disorders in humans

Rutgers Evolutionary Anthropologist Erin Vogel thinks new research published today in Biology Letters, a Journal of the Royal Society, examining how endangered Indonesian orangutans – considered a close relative to humans -- survive during times of extreme food scarcity might help scientists better understand eating disorders and obesity in humans. 

Endangered Indonesian orangutans survive during times of extreme food scarcity and starvation [Credit: Erin Vogel]

"There is such a large obesity epidemic today and yet we don't really understand the basis of the obesity condition or how these high-protein or low-protein diets work," said Vogel, whose research, Bornean orangutans on the brink of protein bankruptcy, represents the first time scientists have looked at how these long-haired, orange-colored apes -- that depend on low-protein fruit to survive -- endure protein cycling, or period bouts of protein deprivation. "I think studying the diets of some of our closest living relatives, the great apes; may help us understand issues with our own modern day diets," she said. 

According to Vogel, an assistant professor of anthropology in Department of Anthropology and Center for Human Evolutionary Studies, in the School of Arts and Sciences, the research shows that it is only during high periods of high caloric and protein intake that orangutans put on fat, a scientific fact that is sometimes ignored by those who believe that high protein, low carbohydrate diets are the best way to lose weight. She said it is only when caloric intake is restricted that orangutans use these fat reserves for energy and eventually dip into their protein (muscle) reserves – a condition that is seen with eating disorders like anorexia. 

Orangutans in particular are interesting to study, Vogel said, because they are the only documented species of non-human ape to store fat when food is abundant in the wild and use these fat reserves when preferred fruits become scarce, presumably something done by our early hominin ancestors. 

Vogel and her research team, analyzed samples collected over a five-year period to study the effects of protein recycling, which included examining urinary metabolites and nitrogen stable isotopes – compounds and byproducts in Orangutan urine. What they determined is that these primates are able to endure prolonged protein deficits without starving to death by consuming higher protein leaves and inner bark and obtaining energy from their stored body fat and even muscles for an extended period of time when low-protein fruit is unavailable. 

"We discovered through this research that the daily amount of protein the orangutans take in when fruit is not available is inadequate for humans and one-tenth of the intake of mountain gorillas. But it is sufficient to avert a severe protein deficit," said Vogel. The Bornean orangutan population has fallen drastically in the last 50 years in Indonesia to less than 55,000 and on the island of Sumatra to less than 5,000 due to a massive amount of illegal logging and further clearing of the land to develop palm oil plantations in their now impoverished rainforest habitat. Vogel says that although some palm oil companies argue that clearing partially logged areas of the rainforest for palm oil plantations is not detrimental to the existence of the orangutan because their natural habitat has already been taken away, this research on protein cycling indicates that even areas that have been partially stripped of trees are better for orangutan survival than no forest area at all. 

Source: Rutgers University [December 13, 2011]

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Research examines college students’ knowledge about eating disorders

They’re the prime demographic for developing eating disorders, yet new research out of the University of Cincinnati suggests that it could be difficult for college students to notice the warning signs. 

On Oct. 31, Ashlee Hoffman, a UC doctoral student in health promotion and education, will present her research, titled, “University Students’ Knowledge of An Ability to Identify Disordered Eating, Warning Signs and Risk Factors,” at the American Public Health Association’s 139th annual meeting and exposition in Washington, DC. 

Disordered eating, Hoffman explains, involves unhealthy habits over time that can lead up to, but may not yet fit the medical diagnoses of an eating disorder such as anorexia or bulimia. 

Hoffman’s poster research presentation is based on her survey of 428 college students. The survey examined whether they could differentiate between the myths and facts surrounding disordered eating, as well as the risk factors and warning signs. 

The survey also revealed that one out of four survey participants reported “lifetime involvement in disordered eating,” and that 50 percent of the participants knew someone who had an eating disorder. 

Hoffman says the majority of the study participants could identify the most common risk factors associated with disordered eating, such as depression and anxiety. However, the students who reported longtime disordered eating were the most unlikely group – among males, females, freshmen, sophomores, juniors and seniors – to correctly identify risk factors. 

The study also found that only a moderate percentage of the students surveyed could identify other risk factors that could trigger disordered eating, such as a recent life change, a critical family member or involvement in a sport that emphasizes being lean. 

Females were significantly more likely than males to know risk factors as well as warning signs of disordered eating, such as abnormal weight loss, purging and distorted body image. 

Hoffman’s survey also found that college freshmen and sophomores were more familiar with the primary risk factors than upperclassmen and graduate students. 

Figures from the National Institute of Mental Health in 2004 found that eating disorders affected 24 million Americans – with the majority of sufferers between the ages of 12 and 25. “Eating disorders hold the highest death rate out of any mental illness affecting this age group, with a large number of cases ending in suicide,” Hoffman says. “The survey also found that some students mistakenly believe disordered eating is a vanity issue, when in fact, it is a compulsive, addictive behavior that sufferers can use as a coping mechanism for stress.” 

Hoffman says that her future research will explore how to better educate college-age students about identifying disordered eating, as well as how to open the doors of communication with friends who they suspect might be struggling with disordered eating. “It’s an issue that’s been long perceived as a taboo subject, partly because of the efforts that people make in hiding disordered eating,” Hoffman says. “If it’s not appropriately addressed in conversation, it can make the problem even worse.” 

Secondary researchers on the study were Keith King, UC professor of health promotion and education, and Rebecca Vidourek, UC assistant professor of human services. 

The APHA Annual Meeting and Exposition is described as the oldest and largest gathering of public health professionals in the world – addressing current and emerging health science, policy and practice in preventing illness and promoting health. 

Source: University of Cincinnati [October 31, 2011]

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Do deficits in brain cannabinoids contribute to eating disorders?

A new report in Biological Psychiatry suggests that deficits in endocannabinoid function may contribute to anorexia nervosa and bulimia. Endocannabinoids are substances made by the brain that affect brain function and chemistry in ways that resemble the effects of cannabis derivatives, including marijuana and hashish. These commonly abused drugs are well known to increase appetite, i.e. to cause the “munchies”. Thus, it makes sense that deficits in this brain system would be associated with reduced appetite. 

Researchers measured the status of the endocannabinoid system indirectly by determining whether there was an increase or decrease in the density of endocannabinoid receptors, called the CB1 receptor, in several brain regions using positron emission tomography, or PET, imaging. They compared these densities in women with anorexia or bulimia with those of healthy women. 

They found global increases in ligand binding to CB1 receptors in the brains of women with anorexia nervosa. This finding is consistent with a compensatory process engaged by deficits in endocannabinoid levels or reduced CB1 receptor function. 

CB1R availability was also increased in the insula in both anorexia and bulimia patients. The insula “is a region that integrates body perception, gustatory information, reward and emotion, functions known to be disturbed in these patients,” explained Dr. Koen Van Laere, the study’s lead author. 

“The role of endocannabinoids in appetite control is clearly important. These new data point to important connections between this system and eating disorders,” added Dr. John Krystal, Editor of Biological Psychiatry. 

Additional research is now needed to establish whether the observed changes are caused by the disease or whether these are neurochemical alterations that serve as risk factors for developing an eating disorder. 

Furthermore, since very few effective treatments exist for these disorders, these data indicate that the endocannabinoid system may be a potential new target for developing drugs to treat eating disorders. Such new therapies are currently being investigated in animal models. 

Source: Elsevier [October 31, 2011]

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