The cells that make up adipose tissue (adipocytes) are not simply fat stores, but rather very dynamic cells that secrete a wide variety of hormones and cytokines essential for metabolic control.
Another aspect that contributes to the complexity of adipose tissue is the existence of two very distinct types of adipocytes, each of them having their own properties:
– the most common “white” adipocytes, which are the main responsible for storing fat in the body;
– the rarer “brown” adipocytes, which on the contrary have the property of “burn” the energy of fats thanks to their high content in mitochondria, the “energy powerhouses of cells” (it is moreover this high quantity of mitochondria that gives cells their brown appearance). In brown adipocytes, the mitochondria specifically contain a protein called thermogenin (UCP-1) which blocks the conversion of fat energy into chemical energy (ATP) and instead causes heat to be produced.
Brown fat: baby fat
Basically, brown fat is therefore a biological adaptation that allows heat to be generated by response to a cold environment and this is why it is found in abundance in animals acclimatized to cold or in those who hibernate. In humans, brown fat is particularly important in newborn babies, most likely to help maintain body temperature following passage of the intrauterine medium (37°C) to the outside environment. In adulthood, on the other hand, this brown fat becomes much rarer (approximately 200 g per person on average) and is mainly localized in the neck, above the collarbones, near the spine and the heart. It seems that thin young women have the highest amounts of brown fat, while obese or diabetic people have none or very little.
Brown fat burns more calories
Brown adipose tissue possesses the characteristic of “burning” a lot of calories and is increasingly considered as a potential therapeutic target for the treatment of obesity. A look at this brown fat, with its very specific properties.
Despite its rarity, certain observations suggest that brown fat could play an important metabolic role. For example, sustained exposure to cold significantly activates the metabolism of these adipocytes, leading to a substantial increase in the body’s energy expenditure. This property suggests that biochemicals or behaviors that specifically activate brown fat metabolism may contribute to the maintenance of normal body weight.
Activate brown fat
Two published studies suggest that this approach could be valid. For example, German scientists have shown that adenosine, a molecule involved in several normal physiological processes, very strongly stimulates the breakdown of fats in brown adipose tissue and promotes the transformation of white adipocytes into brown adipocytes. This transformation of white adipose tissue into brown fat has also recently been observed under certain conditions.
In the meantime, it should be remembered that obesity is not an inevitable disease, but rather a condition extreme which is directly caused by our bad lifestyle habits, especially excess calories. Instead of waiting for the discovery of a possible anti-obesity drug, it is far preferable to attack the problem at the source, by radically modifying eating habits and adopting an active lifestyle. For your waistline, of course, but especially for your health in general.
Ouellet V et al. Brown adipose tissue oxidative metabolism contributes to energy expenditure during acute cold exposure in humans. J Clin Invest; 122: 545-93.
Gnad T et al. Adenosine activates brown adipose tissue and recruits beige adipocytes via A2A receptors. Nature; 516: 395-9.
Sidossis LS et al. Browning of subcutaneous white adipose tissue in humans after severe adrenergic stress. Cell Metab. 29: 200-.
Presse Santé strives to transmit health knowledge in a language accessible to all. In NO CASE, the information given can not replace the advice of a health professional.
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