Protein that Produces "Good" Fat Identified

A pair of studies has made discoveries about the way mammals make and use different types of fat that may one day lead to new treatments for obesity.

Although many people would prefer to have less fat, healthy levels of fat are needed to help regulate metabolism and keep the body warm. There are two main types of fat: white ("bad") fat and brown ("good") fat. White fat is much more common. It stores extra energy and contributes to obesity. Brown fat, on the other hand, burns calories by generating heat. Newborn babies have the most brown fat, while adults are thought to have very little. However, brown fat precursors remain in the body during adulthood.

The first mouse study identified a bone-forming protein, called "bone morphogenic protein 7" or BMP7, which is known to stimulate brown fat development. The researchers found that mice genetically altered to have no BMP7 had less brown fat than non-altered mice. Also, mice treated with artificially high levels of BMP7 had more brown fat than untreated mice, and they burned more calories.

The second study traced the origin of brown fat cells in mice. They found that by turning on a protein, called PRDM16, they could encourage immature muscle cells (called myoblasts) to produce brown fat cells instead. The authors showed that, contrary to what many researchers previously thought, brown and white cells do not share similar origins.

The study results may help provide potential new therapeutic approaches for the treatment of obesity, according to the authors. For example, increasing brown fat cell production may help people burn more calories. However, rigorous research in humans is needed before the results can be translated to people because brown fat appears to function differently in mice.

Comments

[Mark T.]

Although I'm sure research on fat cells and proteins eventually benefits very obese people with major health problems, I worry that it fuels the public search for a "magic bullet" for weight loss. We would do well to remember what research has proved already: a smart, low-fat diet with plenty of fruits and vegetables coupled with regular, moderate exercise goes a long way to achieve and maintain a healthy weight.

[Tim]

I think geneticists should be focused on finding cures for untreatable genetic disorders instead of obesity - which is completely treatable AND preventable. I don't mean to sound insensitive, but obesity is something that can be fixed with a healthy diet and regular exercise. Regardless, I don't think we'll ever stop hunting for that "quick fix" to solve the problem.

[Chantal]

I am not very excited by this story. I just do not think this is the life-changing easy fix for obesity in our country. That being said, more time and money will be spent on this cause, as morbid obesity is on the rise and is a serious health problem in the United States. When the drug Alli™ (orlistat) was released over the counter in 2007, it was the talk of the pharmacy. But then, people were deterred by the price and became educated on the possible GI side effects, and now people are looking for something else to try. I do realize that many people try hard to lose weight, legitimately, and are unable to. Maybe there will be something in the future that can aid this type of population. Perhaps walking is the magic drug we have all been missing.

[Sean]

I guess there could be benefits for people whose obesity is caused by poor metabolisms or other factors outside of their control. Consider the person with Prader-Willi syndrome who cannot regulate their own internal hunger and fullness responses. This is a genetic cause for obesity, as opposed to the behavioral ones that we’re more familiar with. Otherwise, I do agree that behavioral changes are the first steps for healthy lifestyles in the majority of people.

[Madison]

I understand that obesity is both treatable and preventable, but I think part of the reason that researchers try to find that "quick fix" is because many people who are obese feel as though they have no means to become healthy again without experiencing medical problems and possible failure. Research could help identify some potential ways to make it easier for people who are morbidly obese to start their weight-loss treatment. Maybe PRDM16 and brown fat production could be that stepping stone to aid people in losing weight.

[luck]

Though the use of brown-fat-producing proteins to help treat obesity is years and years of research away, I can’t help but already worry about the potential for abuse this discovery has. Presently, I feel many girls and women suffer from supermodel-syndrome, where they yearn/strive to mimic size 0 mannequins and models. Laxative abuse is already a problem, and now the discovery of proteins that help produce good fat to help burn calories? I hope the ultra-thin craze will phase out by the time this discovery becomes widespread.

[jill]

I think it’s important to recognize some personal biases that obviously have influenced people’s comments here. Sometimes I think that being anti-fat people is the last frontier of acceptable discrimination. Yes, there are some people out there who could use diet and exercise to improve their body weights but who choose to do nothing. But I just don’t think that this is the majority. It is difficult for many people to accept obesity as a disease, just as it has been difficult for many to accept alcoholism as a disease.

And similar to treatments for many diseases, there are many barriers to obesity treatments (economic, educational, social, etc.). And obesity presents unique challenges not seen with some other diseases (emotional nature of food, targeted advertising of fast-food to populations prone to obesity and poor penetrance of educational messages regarding lifestyle changes). I believe a lot of progress has been made, but it is important to maintain some sensitivity to the individuals.

[C.Swans]

How far along are we from turning such research into a treatment that we can use? It states that brown fat cells appear to function differently in mice than in humans. If this is the case, how can we decipher any information that is applicable to humans from this study? Brown fat cells are also known as “baby fat,” which provides heat for babies. Unlike the white fat cells, which contain mostly triglycerides and cholesterol, brown fat cells contain large amounts of mitochondria, which is where much of the cell’s energy comes from. I hope that when and if we do turn this research into something we can use to help with our obesity problem, people don't use it as an excuse to eat even more irresponsibly in regards to their health.

[Shawn]

Brown fat has some interesting characteristics. Brown fat is full of mitochondria and full of iron-rich proteins and energy. In infants, it makes up 5% of their body weight, and it virtually disappears by adulthood. The reason why brown fat is common in neonates, small animals in cold environments (like mice) and hibernating animals is because it has the ability to use stored energy as heat.

An interesting study in mice showed that when the brown fat was genetically ablated, they developed obesity without over-eating. Mice do not go through changes in the amount of brown fat present like humans do, and it is going to be difficult to “add” brown fat to humans.

[stefanie c.]

Why DO scientists and researchers keep focusing so much effort on quick-fix weight-loss solutions? Probably because obesity has become an epidemic in this country, and the targeted market is present and growing (pun intended). However, I can understand the hopelessness feeling of those who are obese. Many people turn to food for comfort during times of stress and sadness. Food is a coping mechanism. They then gain weight and result in feeling more insecure and stressed due to the weight gain and thus eat more. It’s a vicious cycle. I think those who are not genetically predisposed to obesity need more social and emotional therapy before beginning drug therapy.

[Big Joe]

Obesity is defined as having a BMI (body mass index) of greater than or equal to 30kg/m^2, which is different than being overweight. Overweight is between 25-29.9kg/m^2. As of 2005, the WHO estimates that 9.8 percent of the population around the world is obese. This amounts to 400 million people worldwide. Since obesity is associated with serious diseases, such as diabetes, cardiovascular disease, sleep apnea and osteoarthritis, it is important to find better treatments for this epidemic.

[Darren]

I agree that obesity is different from other diseases because of the many things involved and the other conditions that can stem from it. I hope this research can lead to a tangible type of treatment for obesity. It is scary to see how greatly obesity is affecting the population, and it is a topic researchers should definitely focus on!

[Howard]

It seems like this can be a tool used in conjunction with other methods for treating obesity. This does not have to be a first-line option, for those of you concerned about a quick fix. Even the Alli label suggests that it must be used in conjunction with increased exercise and a decreased diet, so the basics still apply. Proper health always includes these two factors, regardless of body type.

[danielle h.]

When growing up, most of the mitochondria (which are responsible for the brown color) in brown adipose tissue disappear, and the tissue becomes similar in function and appearance to white fat - as a mere fat deposit. However, recent studies using PET scanning of adult humans have shown that it is still present in many adults in the upper chest and neck. The remaining deposits become more visible (increasing tracer uptake) with cold exposure, and less visible if an adrenergic beta blocker is given before the scan.

[Nire A.]

There are currently multiple treatments for obesity, including a combination of diet, exercise and other lifestyle modifications. Other treatment options are herbs (like green tea) and supplements, fiber, acupuncture, psychotherapy, hypnosis, meditation, and the last option is normally weight-loss surgery. With so many treatment options out there, it is not hard to believe that our quest to find more ways to lose weight exists. Exercise is one of the best treatments for obesity, and it's great for anyone to do — small, medium or large!

[Micky]

Being the country with the most overweight people, I think it’s our country’s large food portions that may contribute to the issue. Up until a few years ago, almost every fast-food restaurant had an option for an “extra-large” meal size. McDonald’s had their “super size” option for an extra 36 cents, if I remember correctly. All you get is more French fries and an extra-large soda, not that the burger is very healthy, but the fries and soda are probably the most unhealthy parts of the meal. The fast-food restaurants seem to have all removed their extra-large meal size options, but it is gimmicks like these that have led to the obesity in our country.

[Norton]

Brown fat cells are important in babies. Since babies have trouble with thermal regulation, because they have a higher surface area to body-mass ratio than adults, and their nervous systems are slower at responding to cold stimuli than adults, the higher amount of brown fat cells help to compensate by creating heat.

[Mike F.]

In response to Micky’s comments regarding fast-food, restaurants have been adding healthier options like salads and lighter meals to the menu. However, some of these “healthy options” contain high amounts of fat and calories from cheese, salad dressings, etc. Often, these choices are high in sodium and sugar also. Be careful when eating out!

[Matthew A.]

I agree with Micky about the fast food craziness that is America. Back in 2001 there was a book by an investigative journalist Eric Schlosser called Fast Food Nation: The Dark Side of the All-American Meal. It examines the local and global influence of the United States fast-food industry. I haven’t read the book yet, but was told that I must. After my friends read it, they refused to eat fast food. Perhaps everyone in America needs to read this book!

[wayne]

Most people seem to focus on obesity that can be prevented, controlled and reduced with personal effort. This type of obesity is obviously more prevalent, but we can’t forget about those whose genetics are the source of their obesity. People probably assume that these patients are obese as a result of their own habits. The percentage of obesity that can be attributed to genetics varies from 6% to 85%, depending on the population examined.

On a population level, the thrifty gene hypothesis postulates that certain ethnic groups may be more prone to obesity when exposed to an equivalent environments. Their ability to take advantage of rare periods of abundance by storing energy as fat would be advantageous during times of varying food availability. Individuals with greater adipose reserves would be more likely survive famine. This tendency to store fat, however, would be maladaptive in societies with stable food supplies. This is the presumed reason why Pima Indians, who evolved in a desert ecosystem, developed some of the highest rates of obesity when exposed to a Western lifestyle.

[Wendi Ashcroft]

In regard to Micky’s comment on fast-food chains, does anyone think that trans fats should be banned from all fast-food chains? Certain states have already placed a ban on trans fats, and certain chains have already completely switched from trans fats to other forms of fats. It would be great if trans fats were removed from the market all together since they contribute to heart disease even more than saturated fats.

[charlotte]

I wonder if this discovery could realistically be applied to humans. They stated that adults have very little brown fat, as compared to infants. If brown fat burns calories by producing heat, and we start increasing the percentage of brown fat in adults, could this cause dangerous increases in the body temperature? I think this discovery will need a lot more extensive research in humans on its possible side effects, as altering body heat production could cause serious consequences.

[SUMA]

The article states that “rigorous research in humans is needed before the results can be extrapolated to people because brown fat appears to function differently in mice;” however, I was not able to locate any articles or information on how brown fat functions differently in mice. Has anyone located this information?

Researcher Bruce Spiegelman, PhD, of Harvard University’s Dana-Farber Cancer Institute said that he felt promoting brown fat growth was a plausible approach to weight control. He published 2 brown fat papers in Nature. Review of other literature states that this study raises further questions about the role of BMP-7 and PRDM 16. A study done on the “new role of BMP-7 in brown adipogenesis and energy expenditure” revealed an important role of BMP-7 in promoting brown adipocyte differentiation and thermogenesis in vivo and in vitro. The authors felt this provided a potential new therapeutic approach for the treatment of obesity. Another study showed that PRDM16 regulates the creation of brown fat from immature cells and knocking out PRDM16 turned them into muscle.

The increasing incidence of obesity in this country and its effect on healthcare costs should be a concern to everyone. An article by the Centers for Disease Control states that obesity increases the risk of many diseases and health conditions, including hypertension, osteoarthritis, dyslipidemia, type 2 diabetes, coronary heart disease, stroke, gallbladder disease, sleep apnea, respiratory problems and some cancers. As a result, I think the findings from this study warrant further research.

[Mel]

White fat cells store energy, and brown fat cells burns energy by generating heat. BMP7 is the protein that is found to be capable of inducing the formation and function of brown fat cells. BMP7, known for its role in bone growth, has been found in studies to increase brown, but not white, fat cells in mice. This leads to decreases in weight gain and increases in energy expenditure.

A study done by researchers at Joslin Diabetes Center showed that BMP7 may produce brown fat playing a role in fighting obesity. Most or all of the studies done so far have been done in mice. More studies need to be done in humans.

[liz]

I agree with Sean that it could benefit those who are obese due to poor metabolism or factors outside of their control. I also agree with the author that further research is needed in humans since brown fat functions differently in mice than people.

BMP7 (bone-forming protein) has therapeutic applications in humans: It can be used to aid in the fusion of vertebral bodies during surgery. It has also shown anti-inflammatory and cytoprotective effects on proximal tubular cells in animal study, which will require further study for potential treatment of chronic kidney disease