Brown Fat, White Fat. Is One Better Than the Other?
Adipose tissue is an underappreciated and misunderstood organ. As obesity rates steadily rise, the riskiest approach to human adipose tissue is to dismiss its importance. People think of fat cells and that's it. However, adipose tissue (fat) has multiple cell types, and they each matter. There are adipocytes (fat cells) — which can be white, brown, beige, or pink — as well as immune cells, fibroblasts, blood vessels, and parts of nerve cells. The main function of white adipose tissue is to store energy in the form of triglycerides. Brown adipose tissue consumes glucose and triglycerides, generating heat. Brown fat cells within depots of white fat are termed brite cells (a portmanteau of brown and white) or beige cells. Pink fat cells have been found in breast tissue in mice.
@vatan White adipose tissue is commonly separated into visceral fat and subcutaneous fat, which have negative and neutral or positive metabolic effects, respectively. It is capable of more than doubling in mass and then returning to baseline. White adipocyte-derived hormones include leptin, which is low in starvation, and adiponectin, which regulates glucose and lipid metabolism. White adipose tissue is essential for the proper function of the reproductive system, including secretion of hormones and lactation. Brown adipose tissue protects newborns from cold as they develop the ability to shiver, and in adults it is found in depots in the neck, shoulders, posterior thorax, and abdomen. The amount of brown adipose tissue varies according to sex and lowers with increasing age and increasing body mass index (BMI). There is much more white fat in the body than brown fat. It appears that activating brown fat leads to beneficial effects on metabolism, though we don't know yet all the steps for how that happens.