Staying in a cool environment may help you stay fit as researchers have discovered that such environment stimulates growth of brown fat that burns energy to generate heat and may protect people from diabetes and obesity.
Ambient temperatures can influence the growth or loss of brown fat in people. Cool environment stimulate growth, warm environment loss, the research showed. Previous studies have shown that people with plentiful brown fat stores tend to be lean and have low blood sugar levels. 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 is unclear.
“The big question until this study was published was whether or not we could actually manipulate brown fat to grow and shrink in a human being,” said endocrinologist Paul Lee from Garvan Institute of Medical Research in Australia.
The results were presented on Sunday, June 22 at ICE/ENDO 2014, the joint meeting of the International Society of Endocrinology and the Endocrine Society in Chicago.
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 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 center 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.
At the end of each month participants underwent a detailed ‘thermal metabolic evaluation’ in a whole room calorimeter. Measurements taken at the end of the first month represented ‘baseline’.
In addition, cold-stimulated PET/CT scans measured brown fat, muscle and fat biopsies revealed tissue metabolic changes.
Independent of the season during which the study was carried out, brown fat increased during the cool month and decreased 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 improvement in insulin sensitivity accompanying brown fat gain may open new avenues in the treatment of impaired glucose metabolism in the future. On the other hand, the reduction in mild cold exposure from widespread central heating in contemporary society may impair brown fat function and may be a hidden contributor to obesity and metabolic disorders,” Lee said.
The authors suggest that recruiting and activating BAT by manipulating temperature may be a promising therapeutic strategy in obesity and diabetes treatment.
The study appeared in the journal Diabetes.