A new study being presented today at ICE/ENDO 2014, the joint meeting of the International Society of Endocrinology and the Endocrine Society in Chicago, 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.
The study results, which clearly show the 'plasticity' of brown fat in humans, are published online today in the journal Diabetes to coincide with the ICE/ENDO meeting.
Lee's previous studies have shown that people with plentiful brown fat stores tend to be lean and have low blood sugar levels. His studies have also shown in the laboratory that ordinary human white fat cells can change into brown fat cells.
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 24 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 19 C for the second month, back to 24 for the third month, and up to
|Contact: Alison Heather|
Garvan Institute of Medical Research