Signs of Depression

Eating disorders in the U.S. among ethnic groups were believed to be rare, but recent studies have shown that a number of cultures are now exposed to the thin beauty ideal. As a result, experts expect to see an increase in eating disorder symptoms among ethnic groups. It is also suspected that eating disorders and weight control behaviors may be increasing among adolescent boys. Eventhough research has shown that eating disorders begin during adolescence, few epidemiological studies have been conducted with teens and those that have examined weight control practices among adolescents are too varied to be able to discern trends.

A new study, one of the first to examine trends in adolescent weight control behaviors over a 10-year period, observed that the prevalence of these behaviors in male adolescents significantly increased, while black females appear to resist pressure to pursue thinness. The study was published online in the International Journal of Eating Disorders (http://www.interscience.wiley.com/journal/eat), the official journal of the Academy for Eating Disorders.

Led by Y. May Chao of Wesleyan University in Middletown, CT, scientists examined data from nationally representative samples of high school students from 1995 to 2005. The data was available via the Youth Risk Behavior Surveillance System (YRBSS), a survey conducted every two years since 1991 by the Centers for Disease Control and Prevention to assess the prevalence of health-risk behaviors among teens.

The results showed that the prevalence of dieting and diet product use among female adolescents significantly increased between 1995 and 2005 and as did the prevalence of all weight control behaviors (including dieting, diet product use, purging, exercise and vigorous exercise) among males. The data suggested that black female adolescents are the least likely to practice weight control, while white female adolescents are the most likely. Among males, white adolescents are the least likely to practice weight control and Hispanic adolescents are the most likely. The authors suggest that Hispanics may be more motivated to control their weight due to the higher prevalence of overweight among these young men.

The increase in weight control behaviors among males indicates that the social pressure for men to achieve unrealistic body ideals is growing, putting young males at an increased risk of body dissatisfaction and developing an eating disorder, as per the authors. Considering that males have negative attitudes toward therapy-seeking and are less likely than females to seek therapy, efforts should be made to increase awareness of eating disorder symptomatology in male adolescents, and future prevention efforts should target male as well as female adolescents, they state.

The study reported the 10-year trends but also showed that some behaviors fluctuated during this period. The authors suggest that some practices, such as dieting, may be sensitive to changes in certain aspects of culture, such as fashion and topics of media focus, or seasonal variations, since it was not known at what time of year the YRBSS was administered.

Surprisingly, unlike prior studies, the current study did not find that ethnic differences in weight control behavior are decreasing. The authors suggest that black women tend to have more flexible concepts of beauty, which may make them less vulnerable to social pressure. However, this may put them at increased risk for becoming overweight, given the current environment of super-sized portions of nutritionally deficient foods.

The authors conclude, Males, particularly ethnic minority males, are under studied in this field, and this study provides key information about the prevalence of weight control practices in a large, diverse sample of male adolescents and raises important questions about the factors contributing to the ethnic difference in weight control practices among male adolescents.


Posted by: Evelyn    Source

Research presented at the 72nd Annual Scientific Meeting of the American College of Gastroenterology observed that obesity, among other important risk factors, was the strongest risk factor for colorectal cancer in women.

Joseph C. Anderson, MD of Stony Brook University in New York (and the University of Connecticut) and colleagues examined data from 1,252 women who underwent colonoscopy. They classified patients as per their age, smoking history, family history of colorectal cancer, and body mass index (BMI). Obesity was defined as a BMI of 30 or higher. For smoking, patients were divided into three groups: heavy exposure, low exposure, and no exposure. Patients who were in the heavy exposure group included women who had smoked more than 10 pack years and who were currently smoking or had quit in the past 10 years.

Eventhough smoking posed a significant increased risk for colorectal neoplasia, scientists observed that for women, obesity was the highest attributable risk factor for developing the disease. BMI accounted for one-fifth of all significant polyps detected during colonoscopy. Of those patients who had colorectal neoplasia, 20 percent were obese and 14 percent were smokers.

Given the increasing number of obese patients in the U.S., identifying them as high risk may have important screening implications, said Dr. Anderson. While obesity is positively linked to an increased risk of colorectal cancer, patients who lower their BMI could potentially reduce their risk of developing the disease in the future.


Posted by: Evelyn    Source

Food has never been more of a global commodity than it is today. But there is an urgent need to understand the problems that face future European food supplies within this global market. And so researchers and policy makers gathered in Budapest last week to push for a more holistic approach to the study of what Europeans eat.

The conference, supported by the European Science Foundation (ESF) and the European Cooperation in the field of Scientific and Technical Research (COST), looked at where food comes from, the ways in which it is processed, packaged and distributed, and how it is sold and eventually eaten.

Researchers at the conference showed that Europeans sitting down at their dinner tables are eating a broader range of meats and vegetables than ten years ago. Europeans demand that their food tastes better, makes them healthier and can be prepared in less time, and yet they want this food available year round at a low price. To meet these needs, food travels a number of more miles; along much more complicated distribution routes than ever before on its journey from the farm to our forks.

This requires a new approach to describing food supply. We're advocating a food systems approach, says Thomas Henrichs, a senior advisor for the National Environment Research Institute in Denmark. The food systems approach includes not only the activities involved in food supply, such as growing and processing a green bean and packing it for distribution, and shipping it, but also the outcomes of eating the green bean on the environment, on the economy and on the health and welfare of the person eating it, explains Henrichs.

One reason to better understand the European food system is the growth in global marketsthe Chinese are eating more meat, and a large market for dairy products is opening up on the Indian subcontinent. Until recently, Europe has invested intensively in its food system in relative isolation, explains Rudy Rabbinge, professor in sustainable development and food systems at Wageningen University in the Netherlands. But Europe must change its food system to take advantage of these new markets, he says.

And with Europes share of global exports predicted to drop from 24 percent to 20 percent over the next 10 years, Europe needs to become more efficient to compete in a global market. Researchers hope that by encouraging different industries within the food chain to think about the food system as a whole, they can increase overall efficiency.

Changes to Europes own food market is another reason to better understand the European food system. An aging European population brings different health demands that could be metin partby altering the food they eat. Migration of people into the EU has changed European food tastes, customs and traditions, and increased wealth gives Europeans the means to buy more meat. Furthermore, longer workdays and the entry of women into the workplace has left a number of Europeans with little time to prepare food, resulting in a reliance on ready-meals. One consequence of this is an average meal contains more ingredients that have travelled further and require more packaging.

Finally, changing energy consumption and the threat of climate change will force Europeans to think about how efficiently they produce and consume food. By studying food systems, researchers hope to understand the socioeconomic, political, and cultural influences on what Europeans eat. And policy makers can use this knowledge to steer how Europe manages the food chainstarting in the field and ending in the stomachto ensure that all people, at all times, have access to sufficient, safe and nutritious food to meet their dietary needs.


Posted by: Evelyn    Source

White bass wild-caught and sold commercially contained significantly higher levels of mercury, arsenic and selenium than fish caught near former industrial areas. The University of Pittsburgh study, abstract number 161184, is being presented at a special session on Contaminants in Freshwater Fish: Toxicity, Sources and Risk Communication, at 8:30 a.m., Wednesday, Nov. 7, at the annual meeting of the American Public Health Association in Washington, D.C.

As per study results, mercury levels were 2.2 to 4.8 times higher in fish caught in the Canadian Lake Erie and available commercially than in fish caught near former iron and steel mills on the Allegheny and Monongahela rivers in Pittsburgh. While several of these mills have been closed for a number of years, the nearby rivers continue to contain high levels of pollution from sewer overflows and active industrial operations.

For the study, scientists used local anglers to catch 45 white bass at two locations in Pittsburgh and bought 10 white bass locally that were caught in the Canadian Lake Erie. They analyzed the fish for levels of mercury, arsenic and selenium. In addition to higher levels of mercury, the store-bought fish had levels that were 1.7 times higher for arsenic and 1.9 times higher for selenium.

We were surprised by our results since we had hypothesized that levels of contaminants in fish would be higher in specimens caught near once heavily polluted sites, said Conrad D. Volz, Dr.P.H., M.P.H., principal investigator, department of environmental and occupational health, University of Pittsburgh Graduate School of Public Health. These results indicate to us that purchasing fish from a local market cannot guarantee food safety. We recommend a more rigorous testing program for commercial freshwater fish with particular attention to fish entering the U.S. from other countries.

As per Dr. Volz, the results also may indicate that sediments in Lake Erie remain contaminated because of only relatively recent reductions in industrial pollution and active coal-fired power plant air emissions from facilities located around and to the southwest of Lake Erie, as well as wastewater from plants located on the lake. Mercury, arsenic and selenium are markers for coal-burning pollution through air emissions and water pollution and from fly ash piles that are absorbed into surrounding soil. Fly ash is the residue left after coal burning that is often stored at the plant site.


Posted by: Evelyn    Source

Researchers can now measure how full or hungry a mouse feels, thanks to a new technique which uses imaging to reveal how neurons behave in the part of the brain which regulates appetite.

Scientists hope the technique, which uses magnetic resonance imaging, will enable a far greater understanding of why certain people become obese when others do not, and why different people have different appetites. The new study, led by scientists from Imperial College London, is described in a paper published recently in the Journal of Neuroscience.

It had previously been very difficult to measure satiety, which is the psychological feeling of being full and satisfied rather than physical fullness. To judge satiety researchers have relied on asking volunteers in trials how full they feel, or watching how much food is eaten, rather than using more objective measures.

Researchers had already identified the part of the hypothalamus area of the brain which regulates appetite. In the new study, the scientists discovered that they could see the neurons there firing if they used a contrast agent of manganese ion to make the neurons visible on a magnetic resonance imaging scan.

When the mouse was hungry and hence the neurons showed increased activity, the contrast agent was taken up, making the neurons light up on the scan. The intensity of this signal decreased as the mouse became less hungry and the neurons became less active.

Researchers already use different contrast agents to look at the anatomy of different cells in the body. The new research is the first to identify which contrast agent is taken up by the hunger neurons and hence allow scientists to observe how they behave in response to different stimuli.

Professor Jimmy Bell, corresponding author of the study from the MRC Clinical Sciences Centre at Imperial College London, said: Appetite and appetite control are important components of why people put on weight. We know very little about the mechanisms behind these processes and why they can vary so much between individuals. In the past we have had to rely on asking people how hungry they feel, this can be very subjective. Furthermore, sometimes your sense of satiety can be significantly affected by other factors such as your mood.

Our new method is much more reliable and completely objective. With murine models, we can now look directly at neuronal activity in the brain. We are working on developing similar methods to study neuronal activity in the appetite centers in people, he added.

For the study, mice given the contrast agent were also given one of two types of hormone. These were either pancreatic peptide YY (PYY), which is known to inhibit appetite, or ghrelin, which is known to increase it. The researchers then monitored the reactions of the hunger neurons to these stimuli. As expected, the intensity of the neurons signals increased when ghrelin was administered and decreased with PYY.


Posted by: Evelyn    Source