Category: Nutrition

NewsPsychology (Aug. 13, 2012) — When it comes to college-age individuals taking care of their bodies, appearance is more important than health, research conducted at the University of Missouri suggests. María Len-Ríos, an associate professor of strategic communication, Suzanne Burgoyne, a professor of theater, and a team of undergraduate researchers studied how college-age women view their bodies and how they feel about media messages aimed at women. Based on focus group research findings, the MU team developed an interactive play about body image to encourage frank discussions about conflicting societal messages regarding weight, values and healthful choices.

Research  presented at the Annual Meeting of the Society for the Study of Ingestive Behavior (SSIB) suggests that both animals and humans find multiple pieces of food to be more satiating and rewarding than an equicaloric, single-piece portion of food.

Increases in portion size lead to increased intake. We investigated here the impact of number and size of food .Both humans and animals use number as a cue to judge quantities of food, with larger numbers usually associated with larger quantities. Therefore, a food portion cut into multiple, bite-sized pieces may perceptually look more and therefore elicit greater satiation than the same portion presented as a single, large piece. E.J. Capaldi and colleagues (1989) showed that when rats were trained to associate one arm of a T-maze with a single 300 mg pellet and another with 4 (75 mg) pellets, they preferred the arm associated with the four pellets. We investigated if a portion of food in single or multiple, bite-sized pieces (both equal-calorie portions) would affect food selection and consumption in rats and humans.

Food-restricted rats were trained to associate one T-maze arm with 30 (10 mg) pellets and another with 1 (300 mg) food pellet. Following training, they were given 12 trials where arm choice and speed to the chosen arm were measured.

The results showed that rats preferred and also ran faster for the arm associated with the multiple (30) 10 mg pellets than that associated with the single 300 mg food pellet. This shows that foods in greater numbers may be more rewarding to animals than an equicaloric, single food pellet.

Here, a sample of 301 college students was given a pre-measured 82 g food portion (bagel) uncut or cut into quarters. Twenty minutes after the bagel was consumed, subjects were told that they could eat as much or as little from a complimentary test lunch (test meal). Any leftover bagel and test meal was then recorded.

Subjects who received the single, uncut bagel ate more calories from both the bagel and the test meal than those who received the multiple-piece bagel. This shows that food cut into multiple pieces may be more satiating than a single, uncut portion of food.

Devina Wadhera, the lead author, suggests that "cutting up energy-dense meal foods into smaller pieces may be beneficial to dieters who wish to make their meal more satiating while also maintaining portion control."

A study recently published in the Endocrine Society's Journal of Clinical Endocrinology and Metabolism (JCEM) suggests that vitamin D — when taken with calcium — can reduce the rate of mortality in seniors, therefore providing a possible means of increasing life expectancy.

During the last decade, there has been increasing recognition of the potential health effects of vitamin D. It is well known that calcium with vitamin D supplements reduces the risk of fractures. The present study assessed mortality among patients randomized to either vitamin D alone or vitamin D with calcium. The findings from the study found that the reduced mortality was not due to a lower number of fractures, but represents a beneficial effect beyond the reduced fracture risk.

"This is the largest study ever performed on effects of calcium and vitamin D on mortality," said Lars Rejnmark, PhD, of Aarhus University Hospital in Denmark and lead author of the study. "Our results showed reduced mortality in elderly patients using vitamin D supplements in combination with calcium, but these results were not found in patients on vitamin D alone."

In this study, researchers used pooled data from eight randomized controlled trials with more than 1,000 participants each. The patient data set was composed of nearly 90 percent women, with a median age of 70 years. During the three-year study, death was reduced by 9 percent in those treated with vitamin D with calcium.

"Some studies have suggested calcium (with or without vitamin D) supplements can have adverse effects on cardiovascular health," said Rejnmark. "Although our study does not rule out such effects, we found that calcium with vitamin D supplementation to elderly participants is overall not harmful to survival, and may have beneficial effects on general health."

Other researchers participating in the study were Alison Avenell, Tahir Masud, Frazer Anderson, Haakon E. Meyer, Kerrie M. Sanders, Kari

 In an effort to reverse the supersize citizens of his city, New York City Mayor Michael Bloomberg has proposed a ban on the sale of large sodas. Experts at the University of Alabama at Birmingham say by focusing on one product we could be missing the big picture in the obesity battle.

In 2009, a team of researchers from the UAB School of Public Health and Purdue University reviewed five randomized trials that studied the effect of drinking sugar-sweetened beverages on body weight.

"We found no significant effect on overall weight reduction as a result of reducing intake of sugar-sweetened beverages," explains Kathryn Kaiser, Ph.D., instructor in the SOPH. "Since this was published, two other randomized trials have been published, and neither showed large effects on weight change."

"My hope for the public debate and our leaders' focus is that we direct energy and resources toward the design and conduct of randomized trials that will definitively answer the questions about actions that can significantly reduce weight. From this type of effort, policies may be better informed," Kaiser says.

Suzanne Judd, Ph.D., assistant professor of biostatistics in the SOPH, doesn't think limiting the sale of larger size sodas will do anything to combat the obesity epidemic.

"I think to say people drinking large sodas at events is the cause of obesity is short sighted and it is making a villain out of something that may not be the true villain," Judd says. "I think that while reducing consumption of sugar sweetened beverages is important, I don't think making it unavailable in certain settings is a way to accomplish that."

Judd adds that individuals are ultimately responsible for their own health and the actions they take related to it.

"People make their own choices and we can't force them into those decisions. A public health effort must be made so they can better understand the consequences of their choices," says Judd.

Kaiser and Judd have no financial interest in, nor have received payments from, any food or beverage company.

If you don't like the taste of pork, the reason may be that your genes cause you to smell the meat more intensely, according to a new study.

Duke University Medical Center scientists, working with colleagues in Norway, found that about 70 percent of people have two functional copies of a gene linked to an odor receptor that detects a compound in male mammals called androstenone, which is common in pork. People with one or no functional copies of the gene can tolerate the scent of androstenone much better than those with two, the researchers said.

Hiroaki Matsunami, PhD, a Duke associate professor of molecular genetics and microbiology, had previously discovered and described the genetics of the odor receptor for androstenone (OR7D4). But it wasn't until a group of pork scientists in Norway contacted him that he launched an experiment to learn more precisely at a genetic level how humans perceive the smell of meat.

The Norwegian team had practical reasons for the study: It was concerned what might happen in Europe if a castration method for swine were outlawed. Currently, female pork meat and castrated male pork meat are sold in Europe. The researchers were curious how consumers might respond to meat from noncastrated males.

The level of androstenone in noncastrated pigs ranges up to 6.4 ppm. In Norway the level of androstenone in immunocastrated (using hormones) pigs is from 0.1 to 0.2 ppm, and in surgically castrated pigs the rate approaches zero.

The findings raise the possibility that more consumers will dislike meat if castration is banned and more meat from noncastrated animals is sold, Matsunami said.

The study was published May 2 online in the PLoS ONE open-access journal.

A total of 23 subjects were recruited: 13 consumers and 10 professional sensory assessors. When all of the subjects were divided into sensitive and insensitive cohorts according to a smell test that was previously devised, all of the androstenone-sensitive subjects had the RT/RT genotype, with two copies of the functional RT gene.

"I was surprised at how cleanly this experiment showed who smelled what," Matsunami said. "The results showed that people with two copies of the functional variant of the gene for that odor receptor thought that the meat smelled worse with higher levels of androstenone added."

For the experiment, the researchers added only biological levels of androstenone to existing pork meat, up to the limit of what might be found in male wild boars.

Matsunami said it would be fascinating to see results done on certain populations, including people in the Middle East, where pork has been omitted from diets for centuries.

"I would also like to know about odor receptor variants in indigenous populations, such as people who live near the Arctic Circle and who never eat these meats. What is their genotype?" Matsunami said. Vegetarians as a group may also have a genetic predisposition against the smell of meat, but all of these ideas need to be scientifically studied, he said.

Matsunami also speculated whether meat inspectors with both copies of the functional variant, who presumably would be more sensitive to higher levels of androstenone, might make different decisions in their jobs.

The availability of the humane genome has given us the tools for revising sensory and consumer science involving flavor perception, said co-author professor Bjørg Egelandsdal of the Institute of Chemistry, Biotechnology and Food Science at the University of Life Science, in Ås, Norway.

"This could be very useful in product development, to learn which flavor sensors are correlated with which flavors. More research is needed, but we may be able to revise the way we recruit consumer groups for evaluating product development."

Another practical solution for meat producers would be to find other compounds that are safe to ingest, but that might block the androstenone receptors to reduce that scent in meat.

Other authors included researchers from the Norwegian Meat Research Centre in Oslo; the Institute of Chemistry, Biotechnology and Food Science at the University of Life Sciences in Ås, Norway; the Nofima research group in Ås, Norway; and Monell Chemical Senses Center in Philadelphia.

Funding was provided by the Norwegian Research Council and the U.S. National Institutes of Health (NIH) and an NIH-HRSA fellowship. No funding came from pork or agricultural industries.

Obese women are more likely to be discriminated against when applying for jobs and receive lower starting salaries than their non-overweight colleagues, a new study has found.

The study, led by The University of Manchester and Monash University, Melbourne, and published in the International Journal of Obesity, examined whether a recently developed measure of anti-fat prejudice, the universal measure of bias (UMB), predicted actual obesity job discrimination. The researchers also assessed whether people's insecurity with their own bodies (body image) and conservative personalities such as, authoritarianism, and social dominance orientation were related to obesity discrimination, as they are related to homophobia and racism.

Psychologist and lead researcher Dr Kerry O'Brien said the nature of the study was initially concealed from the participants to avoid biased results, and simply advertised as a study on whether some people are better at personnel selection than others.

"Participants viewed a series of resumes that had a small photo of the job applicant attached, and were asked to make ratings of the applicants suitability, starting salary, and employability," said Dr O'Brien. "We used pictures of women pre- and post-bariatric surgery, and varied whether participants saw either a resume, amongst many, that had a picture of an obese female (BMI 38-41) attached, or the same female but in a normal weight range (BMI 22-24) following bariatric surgery.

"We found that strong obesity discrimination was displayed across all job selection criteria, such as starting salary, leadership potential, and likelihood of selecting an obese candidate for the job."

The higher a participant's score on the measure of anti-fat prejudice, the more likely they were to discriminate against obese candidates, while those with a more authoritarian personality also displayed discrimination.

Dr O'Brien and co-authors Dr Janet Latner, from the University of Hawaii, and Dr Jackie Hunter, from Otago University, noted that one of the particularly interesting and new findings was that the participants' ratings of their own physical appearance (body image) and importance of physical appearance were also associated with obesity discrimination.

"The higher participants rated their own physical attractiveness and the importance of physical appearance, the greater the prejudice and discrimination," said Dr O'Brien. "One interpretation of this finding might be that we feel better about our own bodies if we compare ourselves and discriminate against 'fat' people, but we need to test this experimentally."

The study is the first to show a relationship between explicit self-report measures of obesity prejudice and obesity job discrimination. In addition, the results suggest that a belief in the superiority of some individuals over others is related to the perception that obese individuals deserve fewer privileges and opportunities than non-fat individuals.

Dr O'Brien added: "Our findings show that there is a clear need to address obesity discrimination, particularly against females who tend to bear the brunt of anti-fat prejudice. Prejudice reduction interventions and policies need to be developed. It's also becoming clear that the reasons for this prejudice appear to be related to our personalities, how we feel about ourselves, with attributions, such as, obese people are lazy, gluttonous etc merely acting as justifications for our prejudice."

NewsPsychology (Apr. 24, 2012) — Today’s busy families often rely on fast food and take-out to keep everyone fed and on schedule. Researchers at The Ohio State University Wexner Medical Center want to know whether those types of food, which are often high in saturated fat, impact the body’s reaction to stress.

The recently launched study is for married couples and conducted by the husband and wife team of Ron Glaser, director of The Ohio State University College of Medicine’s Institute for Behavioral Medicine Research; and Janice Kiecolt-Glaser, a professor at the same institute. Both have spent more than three decades studying stress and its physical effects.

“In the marital studies we conduct, we’re also interested in how close personal relationships can either be protective or make things more difficult,” says Kiecolt-Glaser, who is also principal investigator of the study.

The research is designed to help gain an understanding of the physiological differences in the body’s responses to a fast-food type meal compared to a healthier meal, and how the discussion of a stressful topic can impact health.

As part of the study, married couples are asked to attend two day-long research sessions together at Ohio State’s Clinical Research Center. During each visit, blood samples are taken and the couples eat meals that appear identical. At one visit, the food is high in saturated fat. However, the other meal is low in saturated fat. The couples are asked to discuss a stressful subject in their marriage, such as finances, in-laws, annoying habits, etc. More blood is taken afterward to determine if the stressful discussions influence how the body processes the fat in the food by looking for changes in triglycerides.

“What you’re eating may actually interact with your behavior, to make things worse in terms of your physiological response,” says Kiecolt-Glaser. “In previous studies, when discussions got a little more heated we saw bigger changes in stress hormones and larger changes in immune response. In this study, we theorize that after the high saturated fat meal, a negative discussion might increase physiological responses more steeply.”

Kiecolt-Glaser, Glaser and their team are looking for changes in pro-inflammatory cytokines in the couples’ blood samples. These proteins are part of the immune response and start the healing process after an infection, injury or other tissue damage that leads to inflammation. Previous research by Kiecolt-Glaser and Glaser has shown when stress causes cytokines, particularly interleukin-6 (IL-6), to remain elevated in the blood stream too long, they contribute to long-term inflammation which is linked to a number of age-related diseases including diabetes, osteoporosis, heart disease and cancer. Glaser says stress isn’t the only factor that can keep levels of cytokines elevated; fat can too.

“Fat cells around the abdomen, called adipocytes, also make cytokines. So the more fat you have around your waist, the higher levels of these cytokines you have, and the more health risks you have,” says Glaser who is also a professor of molecular virology, immunology and medical genetics. “It’s really about the processes of how stress affects the body. When we start learning about the processes, then we can try to find ways to modify them.”

The study is expected to wrap up in 2014 and is funded by the National Institutes of Health and the Ohio State Center for Clinical and Translational Science, a collaboration of scientists and clinicians from seven OSU Health Science Colleges, Ohio State’s Wexner Medical Center and Nationwide Children’s Hospital.

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NewsPsychology (Jan. 25, 2012) — New research reveals a fascinating and unexpected molecular partnership within the brain neurons that regulate appetite. The study, published by Cell Press in the January 26 issue of the journal Neuron, resolves a paradox regarding a receptor without its hormone and may lead to more specific therapeutic interventions for obesity and disorders of dopamine signaling.

Ghrelin is an appetite-stimulating hormone produced by the stomach. Although the ghrelin receptor (GHSR1a) is broadly distributed in the brain, ghrelin itself is nearly undetectable there. This intriguing paradox was investigated by Dr. Roy G. Smith, Dr. Andras Kern, and colleagues from The Scripps Research Institute in Florida. “We identified subsets of neurons in the brain that express both GHSR1a and the dopamine receptor subtype-2 (DRD2),” explains Dr. Smith. “Dopamine signaling in the hypothalamus is linked with feeding behavior, and mutations in DRD2 that attenuate dopamine signaling are associated with obesity in humans. We speculated that expression of both receptors in the same neurons might lead to interactions between GHSR1a and DRD2 that modify dopamine signaling.”

The researchers showed that when GHSR1a and DRD2 were coexpressed, the receptors physically interacted with one another. Further, the GHSR1a:DRD2 complex was present in native hypothalamic neurons that regulate appetite. When mice were treated with a molecule (cabergoline) that selectively activates DRD2, they exhibited anorexia. Interestingly, the cabergoline-stimulated anorexia did not require ghrelin but was dependent on GHSR1a and the GHSR1a:DRD2 interaction. These findings suggest that in neurons expressing both GHSR1a and DRD2, GHSR1a alters classical DRD2 dopamine signaling.

“Perhaps most importantly, we showed that a GHSR1a-selective antagonist blocks dopamine signaling in neurons with both DRD2 and GHSR1a, which allows neuronal selective fine-tuning of dopamine signaling because neurons expressing DRD2 alone will be unaffected,” concludes Dr. Smith. “This provides exciting opportunities for designing next-generation therapeutics with fewer side effects for both obesity and psychiatric disorders associated with abnormal dopamine signaling.”

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The above story is reprinted from materials provided by Cell Press, via EurekAlert!, a service of AAAS.

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Journal Reference:

1. Andras Kern, Rosie Albarran-Zeckler, Heidi E. Walsh, Roy G. Smith. Apo-Ghrelin Receptor Forms Heteromers with DRD2 in Hypothalamic Neurons and Is Essential for Anorexigenic Effects of DRD2 Agonism. Neuron, 2012; 73 (2): 317-332 DOI: 10.1016/j.neuron.2011.10.038

Trying to resist that late-night tweet or checking your work email again? The bad news is that desires for work and entertainment often win out in the daily struggle for self-control, according to a new study that measures various desires and their regulation in daily life.

"Modern life is a welter of assorted desires marked by frequent conflict and resistance, the latter with uneven success," says Wilhelm Hofmann of the University of Chicago Booth School of Business. Determining how to best resist desires is not as easy as it seems, according to personality and social psychologists who recently presented new research in San Diego about willpower and food psychology.

Resisting desires

In the new study of desire regulation, 205 adults wore devices that recorded a total of 7,827 reports about their daily desires. Desires for sleep and sex were the strongest, while desires for media and work proved the hardest to resist. Even though tobacco and alcohol are thought of as addictive, desires associated with them were the weakest, according to the study. Surprisingly to the researchers, sleep and leisure were the most problematic desires, suggesting "pervasive tension between natural inclinations to rest and relax and the multitude of work and other obligations," says Hofmann, the lead author of the study forthcoming in Psychological Science.

Moreover, the study supported past research that the more frequently and recently people have resisted a desire, the less successful they will be at resisting any subsequent desire. Therefore as a day wears on, willpower becomes lower and self-control efforts are more likely to fail, says Hofmann, who co-authored the paper with Roy Baumeister of Florida State University and Kathleen Vohs of the University of Minnesota.

Scientists who study the complex interplay between desires and self control say that passing up on temptation is made ever more difficult by the idea that there is no single or clear feeling that alerts us to when our willpower is low. "But we find that when willpower is low, everything is felt more intensely," says Baumeister, author of Willpower: Rediscovering the Greatest Human Strength. "Low willpower seems to turn up the volume on life."

In a series of experiments, Baumeister and his colleagues found that people with low willpower reported more distress in response to an upsetting film and rated cold water as more painful during a cold-water immersion test. They also had stronger desires to open a gift and to keep eating cookies.

Postponing a snack

The effects of willpower depletion explain why so many people have trouble resisting unhealthy food — the more they resist the food, the more they crave it. That's why one group of researchers is looking at ways people can alter their physical cravings. Nicole Mead of Catolica-Lisbon School of Business and Economics and her colleagues tested the notion that postponing consumption of a unhealthy snack to an unspecified future time would reduce the desire for, and therefore consumption of, that snack.

In one experiment, Mead's team gave 105 high school students in the Netherlands a bag of potato chips. Some participants received instructions to either postpone, restrain, or consume the potato chips, while others could choose among the three eating strategies. Over the course of one week, students who initially postponed eating the chips subsequently ate the least amount of the chips, regardless of whether they chose or were given the strategy. They ate even more than those who were instructed to not eat them at all.

"Postponing consumption is an effective strategy that consumers can use for controlling unwanted food-related desires," Mead says. "In modern society, people are absolutely inundated with opportunities to consume, and this strategy may be particularly helpful because it primarily works through desire reduction rather than willpower enhancement." Future research will examine whether the strategy works for other transient impulses, such as spending and sexual desires.

The meal is pushed way, untouched. Loss of appetite can be a fleeting queasiness or continue to the point of emaciation. While it's felt in the gut, more is going on inside the head.

New findings are emerging about brain and body messaging pathways that lead to loss of appetite, and the systems in place to avoid starvation.

Today, scientists report in Nature about a brain circuit that mediates the loss of appetite in mice. The researchers also discovered potential therapeutic targets within the pathway. Their experimental results may be valuable for developing new treatments for a variety of eating disorders. These include unrelenting nausea, food aversions, and anorexia nervosa, a condition in which a person no longer wants to eat enough to maintain a normal weight.

The senior author of the paper is Dr. Richard D. Palmiter, University of Washington professor of biochemistry and an investigator with the Howard Hughes Medical Institute. His co-authors are Dr. Qi Wu, formerly of the UW and now at the Eagles Diabetes Research Center and Department of Pharmacology at Carver College of Medicine, University of Iowa, and Dr. Michael S. Clark of the UW Department of Psychiatry and Behavioral Sciences. Palmiter is known for co-developing the first transgenic mice in the 1980s with Dr. Ralph Brinster at the University of Pennsylvania. His more recent studies are of chemicals that nerve cells use to communicate with each other, their roles in mouse brain development and function, and their relation to behavior.

Palmiter and his colleagues concentrated on a part of the brain, a relay center called the parabrachial nucleus, because it is an important hub for integrating signals from several brain regions to modulate food intake. Nausea, as well as taste aversion or preferences, may originate from signals processed in the parabrachial nucleus.

In this most recent study, the researchers discovered the type and location of brain cells that send signals that agitate the parabrachial nucleus and thereby squelch the ability to eat. They also demonstrate how these signals can be blocked to restore normal appetite and to ward off starvation.

Earlier studies by Palmiter's team and by Dr. Michael Schwartz' team at UW Center for Excellence in Diabetes and Obesity Research showed that certain nerve cells in the brain's hypothalamus play a role in promoting feeding and weight gain. They do so by collating a variety of signals from the body. If these brain cells are destroyed, feeding stops. Meals will be refused and liquid food placed into the mouth will hardly be swallowed.

The researchers later learned that the ensuing starvation is due to the excessive activation of the brain's parabrachial nucleus. The researchers found that starvation could be prevented by improving receptor signaling for a substance called GABA and thereby calm the excited parabrachial nucleus. This intervention had to be done within a critical adaptation period to be successful. GABA is one of the most common neurotransmitters — chemicals that ferry messages to and from nerve cells in the brain.

At first, the scientists were puzzled about the source of the command that turns on the parabrachial nucleus and makes it turn feeding off. Their research fingered two suspects and their locations in the brain. Their studies pointed out nerve cells involved with another neurotransmitter, glutamate, in the part of the brain called the nucleus tractus solitarus. Also contributing to the abnormal activation were cells involved in serotonin signaling. Both drive the hyper-excitability of nerve cells in the parabrachial nucleus that inhibit feeding.

The researchers went on to discover several ways to reinstate normal appetite by interfering with input signaling from these two cell types. They also tested how to censor "don't eat" signals coming from cells in the parabrachial nucleus.

Their studies revealed six interventions that prevented starvation when the cells that modulate food intake in the hypothalamus no longer function. These interventions acted upon various aspects of signaling to and from the parabrachial nucleus, in most cases by disabling or reducing signals or their receptors.

The researchers were able to prevent severe loss of appetite in their mouse model by administering bretazenil, a drug that promotes GABA signaling, or by administering ondansetron, a drug used to prevent nausea and vomiting during cancer chemotherapy. The Palmiter team also used specially constructed viruses to selectively reduce signaling by glutamate — the major excitatory signal in the brain.

The researchers believe that additional progress in dissecting circuits that control feeding will be achieved by identifying genes that are active in specific populations of brain cells within the parabrachial nucleus. Finding such genes will allow investigators to selectively manipulate their activity in the mouse and thereby control feeding behaviors.

This study was supported in part by a grant from the National Institutes of Health's National Institute on Drug Abuse.