Researchers at the University of Porto in Portugal have developed a vaccine that fights obesity by suppressing the hormone ghrelin, which is an appetite stimulant.
“An anti-ghrelin vaccine may become an alternate treatment for obesity, to be used in combination with diet and exercise,” said lead investigator Dr. Mariana Monteiro. In other words, this vaccine may someday be a viable alternative to weight loss surgery.
The vaccine, which was developed through the observation of its effects on lab rats, showed a decrease in food consumption and an increase in calorie burning in mice that received the treatment. The suppression of ghrelin, a hormone found in the gut, can lessen appetite while boosting metabolism, promoting weight loss. Weight loss surgery, such as gastric bypass surgery, also suppresses ghrelin. This can, in part, explain the successful weight loss that most patients experience after having obesity surgery.
Lab mice that were given the vaccine also showed decreased levels of neuropeptide Y (NPY), which is responsible for increasing the appetite signals in the central nervous system...
Wednesday, June 22, 2011
Obesity: Cysteine Plays a Key Role: Amino Acid May Be at Root of Obesity
People with high levels of the amino acid cysteine carry 6-10 kilograms more fat than other people. Norwegian researchers studying this phenomenon are generating knowledge which could help to prevent and treat life-threatening obesity.
"There is a very high correlation between high levels of cysteine and obesity," explains Professor of Nutrition Helga Refsum of the University of Oslo's Department of Nutrition. The question is whether this is a causal relationship. Is much of the body's fat due to a high cysteine level, and if so, what is the connection? Why do some people have higher cysteine levels than others? How much is owing to genetic factors, and how much is affected by diet?
Researchers are now closing in on some answers. A comprehensive study, funded under the Research Council of Norway's funding scheme for independent basic research (FRIPRO), aims to shed light on the underlying biological mechanism linking cysteine to obesity. The project started up in 2010 and will run until 2013.
Cooperation between Oslo and Oxford
As an outstanding young researcher in Norway in 1998, Helga Refsum was awarded a grant which she used to build up a working relationship with Oxford University and Dr. Amany Elshorbagy. Their collaboration led to the discovery of a connection between cysteine and obesity.
The project has evolved into a close collaboration between the University of Oslo and Oxford University, involving several other research institutions as well.
Affects more than weight
Obesity is caused by the intake of more calories than are burned; any surplus is stored as fat in the body. The concept is a simple one at the general level. But at the molecular level, many more facets to this relationship emerge, making it more difficult to pin down. The long, complex biochemical processes of enzymes converting food to energy and building blocks can be affected by many factors. The same is true for the breakdown of fat.
Professor Refsum's research indicates that cysteine plays a key role in how the body metabolises energy, stores fat, and breaks down fat. In this latest project, the researchers will also study how cysteine affects the brain -- for instance, whether cysteine can influence the feeling of being satiated.
Blame our genes
Our genes play a large part in determining our weight.
"We know there is a strong genetic component to the body's weight and fat content," says Professor Refsum, pointing out that 50-80 per cent of body weight is due to genetic factors. "Look at the difference between males and females! Women always have more body fat than men. Nature intended it this way; this is how it should be."
Body fat percentage varies widely between ethnic groups. Taking these differences into account, health personnel tailor their body mass index (BMI) criteria for obesity to different populations.
Genetic factors are undoubtedly involved in cysteine levels, the professor stresses. Indeed, two known genetic conditions demonstrate a clear relationship.
People with the most common form of a genetic condition known as homocystinuria lack one of the enzymes that convert homocysteine to cysteine. These people have low cysteine levels and are extremely slender. By contrast, people with a different genetic condition, Down's syndrome, have 50% more of that same enzyme than normal- and they also have higher-than-average cysteine levels and tend to be overweight.
Public health focus
The connection between cysteine and obesity-related diseases is a major topic of Professor Refsum's research.
"We particularly want to find out if cysteine is associated with obesity-related morbidity -- the myriad of diseases such as diabetes, cardiovascular diseases and certain types of cancer that are associated with obesity. From a public health perspective, it is this aspect of obesity we need to worry about.
With lowered cysteine, mice shed fat
Professor Refsum and her colleagues have demonstrated that reducing cysteine levels leads to weight loss in mice and rats. With subsequent supplements of cysteine, the weight returns -- along with a higher risk of diabetes...
"There is a very high correlation between high levels of cysteine and obesity," explains Professor of Nutrition Helga Refsum of the University of Oslo's Department of Nutrition. The question is whether this is a causal relationship. Is much of the body's fat due to a high cysteine level, and if so, what is the connection? Why do some people have higher cysteine levels than others? How much is owing to genetic factors, and how much is affected by diet?
Researchers are now closing in on some answers. A comprehensive study, funded under the Research Council of Norway's funding scheme for independent basic research (FRIPRO), aims to shed light on the underlying biological mechanism linking cysteine to obesity. The project started up in 2010 and will run until 2013.
Cooperation between Oslo and Oxford
As an outstanding young researcher in Norway in 1998, Helga Refsum was awarded a grant which she used to build up a working relationship with Oxford University and Dr. Amany Elshorbagy. Their collaboration led to the discovery of a connection between cysteine and obesity.
The project has evolved into a close collaboration between the University of Oslo and Oxford University, involving several other research institutions as well.
Affects more than weight
Obesity is caused by the intake of more calories than are burned; any surplus is stored as fat in the body. The concept is a simple one at the general level. But at the molecular level, many more facets to this relationship emerge, making it more difficult to pin down. The long, complex biochemical processes of enzymes converting food to energy and building blocks can be affected by many factors. The same is true for the breakdown of fat.
Professor Refsum's research indicates that cysteine plays a key role in how the body metabolises energy, stores fat, and breaks down fat. In this latest project, the researchers will also study how cysteine affects the brain -- for instance, whether cysteine can influence the feeling of being satiated.
Blame our genes
Our genes play a large part in determining our weight.
"We know there is a strong genetic component to the body's weight and fat content," says Professor Refsum, pointing out that 50-80 per cent of body weight is due to genetic factors. "Look at the difference between males and females! Women always have more body fat than men. Nature intended it this way; this is how it should be."
Body fat percentage varies widely between ethnic groups. Taking these differences into account, health personnel tailor their body mass index (BMI) criteria for obesity to different populations.
Genetic factors are undoubtedly involved in cysteine levels, the professor stresses. Indeed, two known genetic conditions demonstrate a clear relationship.
People with the most common form of a genetic condition known as homocystinuria lack one of the enzymes that convert homocysteine to cysteine. These people have low cysteine levels and are extremely slender. By contrast, people with a different genetic condition, Down's syndrome, have 50% more of that same enzyme than normal- and they also have higher-than-average cysteine levels and tend to be overweight.
Public health focus
The connection between cysteine and obesity-related diseases is a major topic of Professor Refsum's research.
"We particularly want to find out if cysteine is associated with obesity-related morbidity -- the myriad of diseases such as diabetes, cardiovascular diseases and certain types of cancer that are associated with obesity. From a public health perspective, it is this aspect of obesity we need to worry about.
With lowered cysteine, mice shed fat
Professor Refsum and her colleagues have demonstrated that reducing cysteine levels leads to weight loss in mice and rats. With subsequent supplements of cysteine, the weight returns -- along with a higher risk of diabetes...
Nicotine: A cure for obesity?
Many cigarette smokers have shed extra pounds through their otherwise-unhealthy nicotine habit. But now, scientists have identified and isolated the pathways in the brain that are affected by nicotine's appetite suppressants. The research, published in the journal Science, might lead to the development of a healthy, nicotine-based treatment to control obesity. Here, a short guide to the findings:
How did the researchers make their discovery?
It was accidental, actually. Researchers from Yale and Baylor were looking for new drugs to treat depression, when they noticed that mice given nicotine were eating less. The scientists gave the mice a chemical compound that blocked nicotine receptors, and the rodents' appetites returned. Next, the researchers genetically modified some mice to knock out those nicotine receptors. When given nicotine, the mice without nicotine receptors did not lose weight, but mice with the receptors did. The researchers also found that these receptors are independent from those known to trigger tobacco cravings in smokers...
How did the researchers make their discovery?
It was accidental, actually. Researchers from Yale and Baylor were looking for new drugs to treat depression, when they noticed that mice given nicotine were eating less. The scientists gave the mice a chemical compound that blocked nicotine receptors, and the rodents' appetites returned. Next, the researchers genetically modified some mice to knock out those nicotine receptors. When given nicotine, the mice without nicotine receptors did not lose weight, but mice with the receptors did. The researchers also found that these receptors are independent from those known to trigger tobacco cravings in smokers...
Fat affects brain's ability to control weight: study
The relationship between a high-fat diet and obesity may be more complicated than was previously thought, according to a new study unveiled at the annual meeting of the Endocrine Society in Boston.
Eating fatty foods may injure neurons in an area of the brain that controls body weight, found researchers at the Diabetes and Obesity Center of Excellence at the University of Washington in Seattle.
"The possibility that brain injury may be a consequence of the overconsumption of a typical American diet offers a new explanation for why sustained weight loss is so difficult for most obese individuals to achieve," said presenting author Joshua Thaler.
Researchers studied rats and mice fed a high-fat diet - that is, one with a similar fat content to the average American diet - for periods varying between one day and eight months. A detailed analysis was then carried out on the animals' brains.
Within the first three days on the diet, the rodents were consuming nearly double the daily calories that they usually would...
Eating fatty foods may injure neurons in an area of the brain that controls body weight, found researchers at the Diabetes and Obesity Center of Excellence at the University of Washington in Seattle.
"The possibility that brain injury may be a consequence of the overconsumption of a typical American diet offers a new explanation for why sustained weight loss is so difficult for most obese individuals to achieve," said presenting author Joshua Thaler.
Researchers studied rats and mice fed a high-fat diet - that is, one with a similar fat content to the average American diet - for periods varying between one day and eight months. A detailed analysis was then carried out on the animals' brains.
Within the first three days on the diet, the rodents were consuming nearly double the daily calories that they usually would...
Sunday, June 12, 2011
The RNA roots of obesity?
Two upregulated microRNA molecules may lie at the heart of insulin signalling malfunctions, which can lead to obesity and type 2 diabetes, according to researchers in Switzerland. Scientists at ETH Zurich found that silencing the two microRNAs improved glucose sensitivity in obese mice, and in a paper published today (8 June) in Nature, they suggest that the findings may point the way to potential obesity treatments in humans.
“The effects they are showing are quite striking,” said Phillip Scherer, a fat cell physiologist at the University of Texas Southwestern Medical School, who was not involved in the study. The microRNAs studied in the paper were “so blatantly, obviously up-regulated in the obese state.”...
“The effects they are showing are quite striking,” said Phillip Scherer, a fat cell physiologist at the University of Texas Southwestern Medical School, who was not involved in the study. The microRNAs studied in the paper were “so blatantly, obviously up-regulated in the obese state.”...
Yo-Yo Dieting Healthier Than Obesity?
In a recent study comparing lifelong obesity to the weight fluctuations of "yo-yo dieting," it is suggested that it’s better to attempt to lose weight than to not diet and stay obese.
"It is clear that remaining on a stable, healthy diet provides the best outcome for health and longevity," which the study's principal investigator, Edward List, PhD, a scientist at Ohio University, Athens, was quoted as saying.
"However, obese individuals commonly weight cycle — they have repeated intentional weight loss followed by weight regain, often called yo-yo dieting. While yo-yo dieting is thought to be harmful, there is little hard scientific evidence to support that."
In order to verify the long-term health effects of yo-yo dieting, List and his collaborators performed what they call "the first controlled study of a yo-yo diet regimen used for an entire life span" with the aid of mice...
"It is clear that remaining on a stable, healthy diet provides the best outcome for health and longevity," which the study's principal investigator, Edward List, PhD, a scientist at Ohio University, Athens, was quoted as saying.
"However, obese individuals commonly weight cycle — they have repeated intentional weight loss followed by weight regain, often called yo-yo dieting. While yo-yo dieting is thought to be harmful, there is little hard scientific evidence to support that."
In order to verify the long-term health effects of yo-yo dieting, List and his collaborators performed what they call "the first controlled study of a yo-yo diet regimen used for an entire life span" with the aid of mice...
Study links insulin action on brain's reward circuitry to obesity
Researchers reporting in the June issue of Cell Metabolism, a Cell Press publication, have what they say is some of the first solid proof that insulin has direct effects on the reward circuitry of the brain. Mice whose reward centers can no longer respond to insulin eat more and become obese, they show.
The findings suggest that insulin resistance might help to explain why those who are obese may find it so difficult to resist the temptation of food and take the weight back off...
The findings suggest that insulin resistance might help to explain why those who are obese may find it so difficult to resist the temptation of food and take the weight back off...
Anti-obesity vaccine boosts calorie expenditure, curbs appetite in mice
Diet and exercise that are mainstays for treating and preventing obesity might get a boost from a newly developed anti-obesity vaccine found to curb appetite and boost calorie burning in mice...
Nicotine treatment 'could control obesity'
Scientists have identified a group of neurons in the brain responsible for smokers' lack of appetite.
In an article in the journal Science, Yale University researchers describe experiments on mice which found nicotine activates neurons to send signals the body has had enough to eat.
However they are not the same neurons which trigger a craving for tobacco.
As a result, the researchers say nicotine-based treatments could help control obesity.
A research team from Yale University School of Medicine and Baylor College of Medicine in Houston performed a combination of molecular, pharmacological, behavioural and genetic experiments on mice.
They found that nicotine influences a collection of central nervous system circuits, known as the body's hypothalamic melanocortin system, by activating certain receptors.
These receptors, in turn, increase the activity of pro-opiomelanocortin (POMC) neurons, known for their effects on obesity in humans and animals.
Targeting cells
When subjected to nicotine, mice lacking the POMC pathway did not lose weight, but mice with the pathway did...
In an article in the journal Science, Yale University researchers describe experiments on mice which found nicotine activates neurons to send signals the body has had enough to eat.
However they are not the same neurons which trigger a craving for tobacco.
As a result, the researchers say nicotine-based treatments could help control obesity.
A research team from Yale University School of Medicine and Baylor College of Medicine in Houston performed a combination of molecular, pharmacological, behavioural and genetic experiments on mice.
They found that nicotine influences a collection of central nervous system circuits, known as the body's hypothalamic melanocortin system, by activating certain receptors.
These receptors, in turn, increase the activity of pro-opiomelanocortin (POMC) neurons, known for their effects on obesity in humans and animals.
Targeting cells
When subjected to nicotine, mice lacking the POMC pathway did not lose weight, but mice with the pathway did...
Wednesday, June 08, 2011
Adding Tangerines to Your Weight Loss Diet Plan
A recent study based out of the University of Ontario has found that a certain substance found in tangerines has been crucial in preventing obesity in mice. Not only that, but it also helped to protect them from Type 2 Diabetes, another disease also associated with obesity...
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