Adults still have a furnace of brown fat
Adult humans keep deposits of brown adipose tissue that burn fuel to make heat when the body is cold.
Established2 min read
Brown fat's job is non-shivering thermogenesis. Its mitochondria run a protein, UCP1, that lets the proton gradient produce heat instead of ATP. Infants use it to stay warm. It was widely thought to vanish.
In 2009 three groups, using PET scans, showed metabolically active brown fat in adults, switched on by cold and more common in lean people and in winter. The deposits are small — neck, above the collarbones, along the spine. They are real, and they are a tissue the body keeps on purpose.
Caveats
- The amount varies enormously. Some adults show very little on a scan.
- Having brown fat is not a weight-loss method. The calories it burns, in ordinary life, are modest.
Sources
- 1Cypess A. M. et al.. Identification and importance of brown adipose tissue in adult humans. New England Journal of Medicine 360, 2009.