Tel Aviv University research shows fat mass in cells expands with disuse
Over 35 percent of American adults and 17 percent of American children are considered obese, according to the latest survey conducted by the Centers for Disease Control and Prevention. Associated with diabetes, heart disease, stroke, and even certain types of cancer, obesity places a major burden on the health care system and economy. It’s usually treated through a combination of diet, nutrition, exercise, and other techniques.
To understand how obesity develops, Prof. Amit Gefen, Dr. Natan Shaked and Ms. Naama Shoham of Tel Aviv University’s Department of Biomedical Engineering, together with Prof. Dafna Benayahu of TAU’s Department of Cell and Developmental Biology, used state-of-the-art technology to analyze the accumulation of fat in the body at the cellular level. According to their findings, nutrition is not the only factor driving obesity. The mechanics of “cellular expansion” plays a primary role in fat production, they discovered.
By exposing the mechanics of fat production at a cellular level, the researchers offer insight into the development of obesity. And with a better understanding of the process, the team is now creating a platform to develop new therapies and technologies to prevent or even reverse fat gain. The research was published this week in the Biophysical Journal.
Getting to the bottom of obesity
“Two years ago, Dafna and I were awarded a grant from the Israel Science Foundation to investigate how mechanical forces increase the fat content within fat cells. We wanted to find out why a sedentary lifestyle results in obesity, other than making time to eat more hamburgers,” said Prof. Gefen. “We found that fat cells exposed to sustained, chronic pressure — such as what happens to the buttocks when you’re sitting down — experienced accelerated growth of lipid droplets, which are molecules that carry fats.
“Contrary to muscle and bone tissue, which get mechanically weaker with disuse, fat depots in fat cells expanded when they experienced sustained loading by as much as 50%. This was a substantial discovery.”
The researchers discovered that, once it accumulated lipid droplets, the structure of a cell and its mechanics changed dramatically. Using a cutting-edge atomic force microscope and other microscopy technologies, they were able to observe the material composition of the transforming fat cell, which became stiffer as it expanded. This stiffness alters the environment of surrounding cells by physically deforming them, pushing them to change their own shape and composition.
“When they gain mass and change their composition, expanding cells deform neighboring cells, forcing them to differentiate and expand,” said Prof. Gefen. “This proves that you’re not just what you eat. You’re also what you feel — and what you’re feeling is the pressure of increased weight and the sustained loading in the tissues of the buttocks of the couch potato.”
The more you know …
“If we understand the etiology of getting fatter, of how cells in fat tissues synthesize nutritional components under a given mechanical loading environment, then we can think about different practical solutions to obesity,” Prof. Gefen says. “If you can learn to control the mechanical environment of cells, you can then determine how to modulate the fat cells to produce less fat.”
The team hopes that its observations can serve as a point of departure for further research into the changing cellular environment and different stimulations that lead to increased fat production.
From the 11 October 2013 post at Cardiac Exercise Research Group - The K.G. Jebsen Center for Exercise in Medicine’s blog about exercise and cardiac health
There remains little doubt that lack of exercise and a sedentary lifestyle represent key health problems in today’s modern society. A quick search on the World Health Organisation’s (WHO) website and you’ll find that physical inactivity ranks 4th in the global leading risk factors for mortality, with many countries around the world demonstrating a trend for women to be less active than men. While health organisations around the world are making a concerted effort to encourage the general public to incorporate exercise into their leisure and free time, this may not be the only period of our day that is dominated by sedentary behavior. Work forms one of the largest segments of sedentary time for employed individuals, and current trends have shifted parts of the working population into less active, ‘sitting’ jobs.
But what does this mean for our long-term health? One study, published last month in PLoS ONE, aimed to answer this question by assessing the impact of occupational sitting on the risk of cancer, cardiovascular disease, and all-cause mortality from a large number of British men and women. Stamatakis and colleagues gathered data from identical health surveys conducted in England and Scotland between 1994 and 2004. Subjects (5380 women, 5788 men) were classified based on whether the majority of time in their job was spent walking, standing or sitting. Subjects were further categorized on levels of physical activity during free time, alcohol intake, smoking, socioeconomic status, and whether they had cardiovascular disease or cancer at the time of the survey. The mortality rate (number of deaths) was then monitored over a 13 year follow-up period.
The major findings reported by this study were that standing/walking occupations carried a lower risk of mortality from either all-causes or cancer, in women but not men. When the researchers further compared groups based on free-time physical activity levels, they found that in both men and women, high levels of free-time physical activity coupled with a standing/walking occupation was associated with a lower risk of cancer and all-cause mortality versus low free-time activity coupled with sitting occupation. At first glance, it could be easy to take the results at face value, but there are limitations to the study design which the authors themselves highlight: Much of the data is self-reported, which may introduce bias, especially when it comes to levels of physical activity during free-time. In addition, there was no information available on how long individuals had been in their current jobs, nor was there any data for people switching jobs during the 13 year follow-up, which may have eventually placed them into a different category. The findings are also surprising given that a similar study published earlier in the year, found that even moderate free-time exercise was enough to reduce the risk of both cardiovascular and all-cause mortality, regardless of levels of physical activity in work.
The issue still seems unresolved, and it has also been discussed here on the blog earlier. Current exercise recommendations from the Norwegian Directorate of Health suggest daily physical activity levels should be at least 30 min, a total 3.5 hours per week, which has been shown in a number of studies to confer significant benefits to health and an overall decrease in mortality rates. However, a busy lifestyle, coupled with raising a family may make this target difficult to reach during our leisure time, making activity levels at work a significant factor in overall health. Everything is better than nothing, and maintaining a physically active lifestyle outside of work hours will contribute significantly to achieve the health benefits of exercise. However, if you’re still worried and have been sat at your desk for the last few hours, when you reach the end of this sentence, why not stand up and take a walk?
Allen Kelly, post doc at CERG.
- Are Sitting Occupations Associated with Increased All-Cause, Cancer, and Cardiovascular Disease Mortality Risk? A Pooled Analysis of Seven British Population Cohorts (plosone.org)
- Exercising in free time may keep blood pressure healthy (medicalnewstoday.com)
- Exercising During Leisure-Time Tied to Reducing High Blood Pressure Risk (counselheal.com)
- Exercise: What the Research Says (gymlion.com)
- Leisure-time Exercise Could Lower Risk of High Blood Pressure? (ivanhoe.com)
- How Being Sedentary Can Affect Your Health – and Back (badbacksblog.wordpress.com)
- Exercise Statistically As Effective As Drugs For Heart Disease, Diabetes And Many Other Diseases (naturalblaze.com)
A new study, supported in part by the National Heart, Lung, and Blood Institute (NHLBI) of the National Institutes of Health, suggests that a combination of mobile technology and remote coaching holds promise in encouraging healthier eating and physical activity behavior in adults. The study focused on the best way to change multiple health behaviors.
The study results will appear Monday, May 28, in the Archives of Internal Medicine, with an accompanying commentary authored by William Riley, Ph.D., a clinical psychologist and program director for the NHLBI.
Scientists from the Northwestern University Feinberg School of Medicine, Chicago, along with colleagues from other institutions, studied 204 overweight and obese adults. Prior to enrollment, participants had a diet high in saturated fat and low in fruits and vegetables. They also engaged in little daily physical activity and had high amounts of sedentary leisure time.
Each participant was assigned to one of four groups:
- Increase fruit and vegetable intake and increase time in moderate/vigorous physical activity
- Increase fruit and vegetable intake and reduce time in sedentary leisure activities
- Decrease fat intake and increase time in moderate/vigorous physical activity
- Decrease fat intake and decrease time in sedentary leisure activities
All participants received mobile devices and were trained on entering information about their daily activities and eating patterns. Coaches studied the data received and then phoned or emailed participants to encourage and support healthy changes during the three-week study. Participants were also asked to continue to track and submit their data over a 20-week follow-up period. Financial incentives for reaching study goals during the study and continuing participation during the follow-up period were offered.
All four groups showed improvements in reaching the assigned health goals, with the most striking results occurring in the group asked to increase fruit and vegetable intake and reduce sedentary leisure activities. The researchers found after 20 weeks of follow up that this group’s average daily servings of fruits and vegetables increased from 1.2 to 2.9; their average minutes per day of sedentary leisure activity dropped from 219.2 to 125.7; and the percentage of saturated fat in their daily calories went from 12 to 9.9.
In his commentary, Riley noted that the use of mobile technology to improve cardiovascular health is worth further study of the effects on health outcomes and costs. Mobile technology offers the chance to deliver key health messages without waiting for intermittent visits with health care providers, he said.
- Leaving the couch, eating more fruits and vegetables may lead to sustained … – CBS News (cbsnews.com)
- Just Making Two Lifestyle Changes Spurs Big And Lasting Results (medicalnewstoday.com)
- How Your Phone Could Help You Lead A Healthier Lifestyle (huffingtonpost.com)
- NIH-funded study – mobile technology used to improve diet and activity behavior (ehrandsocialservices.com)
- Study examines use of mobile technology to improve diet, physical activity behavior (medicalxpress.com)
- Cash, Coaching May Boost Healthy Living (nlm.nih.gov)
- NIH-funded study examines use of mobile technology to improve diet and physical activity behavior (eurekalert.org)
- Cash, Coaching May Boost Healthy Living (news.health.com)
Simply ejecting your rear from the couch means your hand will spend less time digging into a bag of chocolate chip cookies.
That is the simple but profound finding of a new Northwestern Medicine study, which reports simply changing one bad habit has a domino effect on others. Knock down your sedentary leisure time and you’ll reduce junk food and saturated fats because you’re no longer glued to the TV and noshing. It’s a two-for-one benefit because the behaviors are closely related.
The study also found the most effective way to rehab a delinquent lifestyle requires two key behavior changes: cutting time spent in front of a TV or computer screen and eating more fruits and vegetables. …
- #Key of Lifestyle (leggotunglei808.wordpress.com)
- Less Couch Means Less Junk Food (abcnews.go.com)
- Health study: Stop couch surfing and you’ll eat less junk food (thestar.com)
- How Two Key Lifestyle Changes Can Help Boost Your Health Overall (healthland.time.com)
- Less couch time equals fewer cookies (eurekalert.org)
- 2 Tiny Habits That Can Improve Your Overall Health (blisstree.com)
- Cash, Coaching May Boost Healthy Living (news.health.com)
- Study: Improve your diet with less TV time (boston.com)
Excerpt from the article
…For decades, hundreds if not thousands of studies have examined the relationship between our activity levels and our health. Only recently have researchers turned their attention to the consequences of sitting at a desk all day and lying on the couch all evening.
“We’re talking extensively and producing public health messages about what we don’t do. And we don’t talk at all about what we do do: We don’t move very much, but we do sit idle,” says Dr. Mark Tremblay, director of healthy active living and obesity research at the Children’s Hospital of Eastern Ontario Research Institute.
The average person now spends 9.3 hours a day sitting. People who sit for six or more hours per day are 40 per cent more likely to die within 15 years compared to someone who sits less than three hours a day, even if they exercise. Obese people sit 2½ hours more each day than people of normal weight, according to data compiled by Medical Billing and Coding, a U.S.-based organization….
- Is Your Desk Job Killing You? (bigthink.com)
- Bad Office Chairs: Crippling Workers in the European Union – Until Now. (prweb.com)