Metabolism

The ICEMAN Study: How Keeping Cool Could Spur Metabolic Benefits

Support.Thermometer.Temperature2A new study demonstrates that ambient temperatures can influence the growth or loss of brown fat in people. Cool environments stimulate growth, warm environments loss.

Brown fat, also known as brown adipose tissue, is a special kind of fat that burns energy to generate heat. It keeps small animals and babies warm, and animals with abundant brown fat are protected from diabetes and obesity. How brown fat is regulated in people, and how it relates to metabolism, have been unclear.

Endocrinologist Dr Paul Lee from Sydney’s Garvan Institute of Medical Research, recently undertook The Impact of Chronic Cold Exposure in Humans (ICEMAN) study at the National Institutes of Health (NIH) in Washington, funded as an NHMRC Early Career Research Fellow.

For the ICEMAN study, 5 healthy men were recruited and exposed to four month-long periods of defined temperature — well within the range found in climate-controlled buildings — at the NIH Clinical Centre. They lived their normal lives during the day, and returned each night to the centre, staying for at least 10 hours in a temperature-regulated room.

For the first month, the NIH rooms were maintained at 24º C, a ‘thermo-neutral’ temperature at which the body does not have to work to produce or lose heat. The temperature was then moved down to 19º C for the second month, back to 24º for the third month, and up to 27º for the fourth month.

Independent of the season during which the study was carried out, brown fat increased during the cool month and fell during the warm month.

Among the metabolic benefits of increased brown fat was heightened insulin sensitivity. This suggests that people with more brown fat require less insulin after a meal to bring their blood sugar levels down.

“The big unknown until this study was whether or not we could actually manipulate brown fat to grow and shrink in a human being,” said Dr Lee. “What we found was that the cold month increased brown fat by around 30-40%.”

“So in addition to unhealthy diet and physical inactivity, it is tempting to speculate that the subtle shift in temperature exposure could be a contributing factor to the rise in obesity.”

Read the full story.

Source: Garvan Institute of Medical Research. “The ICEMAN study: How keeping cool could spur metabolic benefits.” ScienceDaily. ScienceDaily, 22 June 2014.

Want to become a member of Club One Fifty? Click here to initiate your membership.

Novel Approach to Accelerate Metabolism Could Lead to New Obesity Treatment

Body.Overweight.Obese2By manipulating a biochemical process that underlies cells’ energy-burning abilities, investigators at Beth Israel Deaconess Medical Center (BIDMC) have made a novel discovery that could lead to a new therapy to combat obesity and diabetes. Published in the journal Nature, the new findings show that reducing the amount of nicotinamide N-methyltransferase (NNMT) protein in fat and liver dramatically reduces the development of obesity and diabetes in mice.

“With this discovery, we now have a means of metabolic manipulation that could help speed energy production and lead to weight loss,” explains senior author Barbara Kahn, MD, Vice Chair of the Department of Medicine at BIDMC and George Richards Minot Professor of Medicine at Harvard Medical School. “Our findings are particularly exciting because the antisense oligonucleotide [ASO] technology we used to inhibit the NNMT gene in our study is already being used to treat other diseases in humans.”

The new findings hinge on a biochemical mechanism known as a futile cycle, in which cellular reactions are sped up, thereby generating more energy. “We all know people who can seemingly eat whatever they want and not gain weight,” explains Kahn. “Part of the reason for this natural weight control owes to basal cellular metabolism – the body’s inherent rate of burning energy. A futile cycle is one way to speed up energy utilization in cells.”

Check the full article.

Source: Beth Israel Deaconess Medical Center. “Novel approach to accelerate metabolism could lead to new obesity treatment.” ScienceDaily. ScienceDaily, 9 April 2014.