Discovering Brown, White & Beige Fat Cells
Brown Fat
Brown adipose tissue, a functional organ commonly known as BAT. A unique adipocyte that can burn calories and generate heat by the process of oxidizing glucose and lipids (fat) in the body. The production of generated heat is created by the process of uncoupling protein 1 (UCP1), an inner membrane mitochondrial protein located within BAT cells. Having small amount of lipids and high amounts of mitochondria organelles, provides its brown-cell color, (hints, why scientist describe it as brown fat) making it a key site for thermogenesis to occur. Thermogenesis takes place when triggered by the ingestion of food, during prolonged exposure to cold temperatures and during exercise.
BAT originality found in mammals, later discovered to be in humans, is highly regulated by the sympathetic nervous system (SNS) to increase body temperature when exposed to temperatures below thermoneutrality. In humans, newborn babies have lots of brown fat that help regulate body temperature until they can burn fat on their own. This is because babies do not have the ability to shiver, so they need a lot of brown fat to help keep their bodies warm during infancy stages. As one gets older, inactivation of brown fat begins to occur and decreases in adults with an increase of age, BMI and in high glucose (sugar) levels. Some lean individuals can retain their BAT, as well as individuals who live in cold environment, such as northern polar regions (Alaska & etc.).
White Fat
Compared to white adipose tissues (WAT), that doesn’t burn calories, but is a major sight for excess energy storage (in the form of triglycerides) is about 80% of total body fat, mainly located under the skin (subcutaneous fat) and around internal organs (visceral fat). These cells are mainly consumed of one single enlarged lipid droplet that upholds most of the space in the cell. Leaving other organelles including very few mitochondria, pressed outward the sides of the cell walls. Therefore, functions of thermogenesis will not occur here. Their functions include secretions of hormones, cytokines and adipokines by the endocrine system, immune system effects, metabolism regulation, inflammation, and thermal functions which help keep people warm.
Beige Fat
Beige fat, also carries a few scientific names as Brite fat or brown-in-white fat. These cells are often subcutaneous fat that begin taking on characteristics of brown fat. They originate as WAT, but under certain circumstances they are stimulated to take on BAT characteristics. When beige fat cells are under a microscopic view, visibility of progressed mitochondria and UPC1 expressions are visible. Therefore, can have potential to burn calories by undergoing thermogenesis within the cell.
Can Brown Fat Fight Against Obesity?
When BAT was discovered in humans, it became an attractive target for anti-obesity and type 2 diabetes (T2DM). This is due to its interesting capability of being able to chew up calories. Having less or inactive BAT contributes to obesity. So, I can see why this can be a popular topic for scientist who have researched and experienced BAT. With good testing methods, it can create opportunity to discover treatments to support obesity and T2DM patients. Patrick Schrauwen, one of the first researchers to discover BAT, proved in his experiment that BAT can increase when people are in a cold environment (16 degree celsius) for two hours. Due to this, I do believe BAT can be a good way to fight obesity because of its thermogenesis effects. However, I don’t think most people would realistically want to be in a cold environment for long periods of time for their BAT to increase. Some challenges would be finding patient’s willing to tolerate an uncomfortable environment of this magnitude, not only 2 hours a day, but also the ongoing length of timeframe it would require. Many people may not have the time to continue this process on a regular basis (including variables of days, months, or years). Any new developed of BAT, would have to be enough to make a significant impact on any health benefits but unfortunately, scientist have not been able to achieve this goal, more research and test are needed to determine if BAT can be used to fight obesity.
In the meantime, you can think of this the next time you take a skiing trip or visit the snowy mountains for several hours. Your brown fat could possibly be thanking you for being rejuvenated!
Namaste!
Bibliography:
Sanchez-Delgado G, et. al. Activating brown adipose tissue through exercise (ACTIBATE) in young adults: Rationale, design and methodology. Contemporary Clinical Trials. 2015. www.elsevier.com/locate/conclintrial.
Grens K. Warming up to brown fat. The Scientist Magazine. 2015. file:///Users/melissa/Downloads/Warming%20Up%20to%20Brown%20Fat%20_%20The%20Scientist%20Magazine%C2%AE%20(2).pdf.
Lambert C. Grow fat, get thin? we put brown fat to the test. NewScientist. 2015. https://www.newscientist.com/article/dn27265-grow-fat-get-thin-we-put-brown-fat-to-the-test/.
Myers A. Lean Optimal metabolism & healthy weight loss support. www.amymyersmd.com Web site. https://www.amymyersmd.com/products/lean-metabolism-support?rfsn=5866762.c622d93&utm_campaign=Affiliate_Santiago. Updated 2024. Accessed April, 2024.