Brown fat

Brown Fat or Brown Adipose Tissue (BAT) is a type of adipose tissue that is primarily found in newborns and hibernating mammals. Unlike white adipose tissue (WAT), which stores energy in the form of lipids, brown fat is specialized in energy expenditure. It is so named because of its brown color, which is due to the high density of mitochondria and rich vascularization.

Function

Brown fat's primary function is to generate heat. This is particularly important in newborns and hibernating mammals, who cannot shiver to maintain their body temperature. The process of heat generation, known as thermogenesis, is triggered by the sympathetic nervous system in response to cold exposure. Brown fat cells contain a unique protein called uncoupling protein 1 (UCP1), which allows them to convert the energy stored in lipids directly into heat.

Distribution

In humans, brown fat is found in significant amounts only in newborns, where it makes up about 5% of the body mass and is located mainly in the neck and upper chest. In adults, the amount of brown fat is greatly reduced, and its distribution is more scattered. However, recent studies have shown that adult humans do retain some brown fat, which can be activated by cold exposure.

Clinical significance

Brown fat has been the subject of intense research in recent years due to its potential role in combating obesity and related metabolic disorders. Because brown fat burns calories to generate heat, it could potentially be used to increase energy expenditure and thus promote weight loss. However, more research is needed to fully understand the mechanisms of brown fat activation and to develop safe and effective strategies for its therapeutic use.

See also

• Adipose tissue
• White adipose tissue
• Thermogenesis
• Uncoupling protein