If you think all body fat is bad, think again! Brown adipose tissue (BAT) also known as the ‘good fat’, is a unique type of fat that can not only help you lose weight but also improve insulin sensitivity and lower your risk of metabolic diseases. While white adipose tissue (WAT) is the type of body fat we’re all familiar with, it’s actually brown fat that has been garnering more attention from scientists and health enthusiasts alike. In this blog post, we’ll take a closer look at the three types of adipose tissue – WAT, BAT, and beige adipose tissue – and explore ways to activate and increase the metabolic activity of brown fat, potentially leading to improved weight loss and metabolic health.
The Skinny on Fat–Brown, White, and Beige
White adipose tissue (WAT)
White adipose tissue (WAT) is the most abundant type of fat in the body and is responsible for storing excess energy in the form of triglycerides. There are two main types of white adipose tissue: visceral and subcutaneous. Visceral fat is located in the abdominal cavity, and surrounding organs such as the liver, pancreas, and intestines. This type of fat is more metabolically active and is associated with a higher risk of metabolic diseases such as type 2 diabetes and cardiovascular disease.(1) Subcutaneous fat is located directly beneath the skin throughout the body. This type of fat is less metabolically active than visceral fat and is generally considered less harmful to health. However, excessive accumulation of subcutaneous fat can also lead to obesity and related health problems.
Brown adipose tissue (BAT)
Brown adipose tissue (BAT), commonly known as brown fat, is a unique type of adipose tissue that differs from the more commonly known white adipose tissue in terms of its cellular structure, metabolic function, and distribution throughout the body. Brown fat is packed with mitochondria, which are responsible for generating heat in the body through a process called thermogenesis. This heat production is essential for maintaining body temperature and preventing hypothermia, especially in newborns and hibernating animals. When activated, brown fat can burn up to 20% of the body’s calories, which is significant compared to white fat, which has very little thermogenic capacity.(2) BAT is more abundant in infants and decreases with age but is found in the neck, upper back, and chest, with small amounts found in the adrenal glands and around the kidneys in adults.
Beige Fat
Beige fat, also known as Brite (brown-in-white) or recruitable brown fat, is a subtype of BAT that has the ability to undergo a process called adipose tissue browning, in which it transforms from a white adipocyte-like cell to a brown adipocyte-like cell. This browning process involves the activation of specific transcription factors and the upregulation of genes involved in mitochondrial biogenesis and thermogenesis. As a result, beige fat can produce more energy by burning fatty acids and glucose, which is then released as heat to maintain body temperature. Adipose tissue browning can occur naturally in response to cold temperatures, exercise, or certain dietary interventions.
Studies have shown that increasing the amount and activity of beige and brown fat in the body can have significant metabolic benefits, including improved glucose and lipid metabolism, insulin sensitivity, and overall energy expenditure.(3) This has led to the development of various strategies to target these types of fat as a potential therapeutic approach for treating obesity and related metabolic disorders.
Turn Up the (Internal) Heat–Thermogenesis Explained
Generating body heat requires a significant amount of energy, which in turn prompts the body to utilize its surplus fat reserves as a source of fuel. Brown fat thermogenesis is a fascinating process that plays a crucial role in regulating body temperature and energy expenditure. The process is initiated when the sympathetic nervous system releases norepinephrine (aka noradrenaline). Noradrenaline is the primary neurotransmitter released by sympathetic nerves that innervate brown fat, and it binds to beta3-adrenergic receptors on the surface of brown fat cells to activate thermogenesis. This stimulates a cascade of biochemical reactions that ultimately leads to the activation of the protein UCP1 (uncoupling protein 1), which is found in the inner membrane of brown fat cells.
UCP1 acts as a proton transporter, dissipating the proton gradient across the inner mitochondrial membrane and generating heat in the process. This process, known as uncoupled respiration, allows brown fat cells to burn stored fat to generate heat without producing ATP, the energy currency of the cell. It is also known as non-shivering thermogenesis, as it does not involve muscle contractions like shivering.
Research has shown that brown fat thermogenesis may play a role in regulating body weight and metabolic health. People with more active brown fat have been found to have lower levels of obesity and metabolic disorders such as type 2 diabetes. Therefore, brown fat thermogenesis has emerged as a potential target for developing novel therapies for obesity and related metabolic disorders.
Health Benefits of Brown Fat
Regulate Body Weight
Brown fat has been shown to regulate body weight by increasing metabolism and burning calories. It is estimated that just 2 ounces of brown fat can burn up to 400-500 calories daily. Moreover, research has found that people with higher levels of brown fat have a lower body mass index (BMI) and are less likely to be obese or overweight.(4)
Increase Insulin Sensitivity
Brown fat may be key to maintaining healthy blood sugar levels. Studies have found that activating brown fat improves glucose metabolism and increases insulin sensitivity.(5) This means that brown fat may help the body better regulate blood sugar levels, which is crucial for individuals with diabetes or those at risk of developing the condition.
Improve Heart Health
The benefits of brown fat extend beyond its ability to burn calories. Brown fat may also help reduce the risk of heart disease by improving lipid and cholesterol metabolism. A study published in the European Heart Journal found that individuals with higher levels of brown fat had lower levels of triglycerides and LDL (bad) cholesterol, and higher levels of HDL (good) cholesterol.(6) This suggests that brown fat may play a protective role in cardiovascular health and could potentially be a target for the prevention and treatment of heart disease.
Boost Bone Strength
Besides its metabolic benefits, brown fat may play a role in improving bone health by increasing the production of osteocalcin, a hormone that helps build and strengthen bones. Research published in the Journal of Clinical Endocrinology & Metabolism found that individuals with more brown fat had higher levels of osteocalcin and overall better bone health.(7) Moreover, a study published in the Journal of Bone and Mineral Research found that brown fat activation through cold exposure improved bone mineral density in healthy individuals.(8)
Better Brain Function
The benefits of brown fat extend to the brain as well. Brown fat may play a role in improving brain function by increasing the production of a hormone called brain-derived neurotrophic factor (BDNF), which is important for learning and memory. A study published in the journal Cell Metabolism found that activating brown fat increased the production of BDNF in the brain.(9) This suggests that brown fat may have the potential to improve cognitive function and could be a target for the prevention and treatment of neurodegenerative diseases. Additionally, a study published in the Journal of Cerebral Blood Flow & Metabolism found that individuals with more brown fat had better cognitive function and were less likely to develop dementia.(10)
How To Increase Brown Fat
Deliberate Cold Exposure
Cold exposure therapy has become increasingly popular in the wellness world. Its benefits are widely discussed, and for good reason; it can have a significant positive impact on overall health. Cold exposure, in particular, has been shown to be a potent activator of adipose tissue browning. This is because cold temperatures stimulate the release of norepinephrine, a hormone that signals the activation of brown fat cells and the conversion of white fat cells into brown-like cells. This process not only increases energy expenditure and promotes weight loss but also improves metabolic health by reducing inflammation and insulin resistance.
When we are exposed to cold temperatures, our body starts to shiver in order to generate heat and maintain body temperature. This process is called mitochondrial uncoupling. Shivering is a reflexive muscle contraction that generates heat through the production of energy. The heat generated from shivering activates brown fat, which then burns calories to produce more heat. Research suggests that when shivering occurs, it triggers the release of a molecule called succinate, which acts on the brown fat to increase its thermogenic activity and fat burning.(11) Succinate is a metabolic intermediate that is involved in the citric acid cycle, a key metabolic pathway that produces energy in the form of ATP. By activating brown fat thermogenesis, succinate helps to increase the body’s energy expenditure, which in turn can lead to weight loss, and greater metabolic health.
According to experts, immersing oneself in cold water for 11 minutes each week can boost brown fat levels in the body. To begin, start with a temperature of approximately 68°F (20°C) and gradually decrease it over time to around 50°F (10°C). It is typical to feel uncomfortable and have the urge to exit the water during cold exposure. However, this discomfort indicates that the body is generating heat and activating brown fat. With consistent exposure, the body can acclimate to the cold and eventually become more comfortable in chilly temperatures. Nonetheless, it’s critical to limit exposure time to avoid hypothermia or other health concerns.
Exercise
Research has shown that exercise can stimulate the activity of BAT, which in turn can have a positive impact on metabolism and body composition. Specifically, exercise has been found to increase the activity of uncoupling protein 1 (UCP1).(12) As previously mentioned, UCP1 is a protein that is critical for the function of brown fat. Exercise can also influence the production of hormones that control body fat and lean muscle mass development. One such hormone is irisin, which is released by muscle cells during physical activity.
Irisin helps to convert white fat into brown fat, essentially “browning” white fat and enabling it to become more metabolically active like brown fat. Irisin has also been found to have a number of other metabolic benefits, including stabilizing blood sugar levels and promoting the uptake of glucose into cells.
Sleep
Sleep is a crucial aspect of our daily routine, and it plays a vital role in maintaining overall health and well-being. One of the lesser-known benefits of a good night’s sleep is its impact on brown fat. During sleep, the body goes through different stages, including REM (Rapid Eye Movement) and non-REM sleep. Research suggests that brown fat activity increases during REM sleep and decreases during non-REM sleep. A study published in the Journal of Clinical Endocrinology and Metabolism found that individuals who slept for five hours or less per night had significantly lower brown fat activity than those who slept for seven to nine hours.(13)
The reason behind this correlation is not entirely clear, but it is believed that sleep helps regulate hormones that stimulate brown fat activity. One such hormone is melatonin, which is produced during sleep and has been shown to increase brown fat activity in animals. In addition to its impact on brown fat, sleep also plays a crucial role in overall metabolic health. Chronic sleep deprivation has been linked to an increased risk of obesity, type 2 diabetes, and cardiovascular disease. Lack of sleep can also lead to hormonal imbalances, including an increase in cortisol, which can further disrupt metabolic processes.
Implement Stress Reduction Strategies
When the body is under stress, the release of stress hormones such as cortisol can interfere with the function of brown fat and may contribute to metabolic dysfunction over time. Cortisol has been shown to inhibit the activation of brown fat, and can also cause a decrease in the number of brown fat cells in the body. When we are under stress, we are more likely to make not so healthy food choices, and may become more sedentary and unmotivated to keep up with regular physical activity (even though we know how important they are for reducing stress) which can also impact the activation of brown fat. Engaging in relaxation techniques like progressive muscle relaxation, meditation, yoga, and breathwork exercises can help to mitigate ill effects of stress. For a more in depth look at different breathing techniques, check out my previous blog HERE.
Dietary Additions to Boost Brown Fat
Along with the strategies listed above, there are specific foods you can incorporate in your diet to increase BAT activation.
- Spicy Foods: Spicy foods contain a compound called capsaicin, which can enhance brown fat activation through the sympathetic nervous system response as soon as the spice hits your tongue. Capsaicin can be found in chili peppers, cayenne pepper, and other hot peppers. Black pepper, ginger, and cloves have a similar effect.
- Green Tea: Green tea is high in a type of flavonoid called catechins, which activates mitochondrial uncoupling and brown fat metabolism. Catechins can also be found in cocoa, apples, and berries.
- Omega-3 Fatty Acids: Omega-3 fatty acids, which are found in fatty fish such as salmon, sardines, and mackerel, have been shown to intensify BAT activation. Omega-3s can also be found in walnuts, chia seeds, and flaxseeds.
- Fiber: Foods high in fiber, such as whole grains, fruits, and vegetables, have been shown to increase brown fat activity. Fiber can also help regulate blood sugar levels and promote satiety, making it easier to maintain a healthy weight.
- Resveratrol: Resveratrol is a compound found in grapes, berries, and red wine. Studies have shown that resveratrol can increase brown fat activity and improve metabolic health.(14)
By incorporating these strategies into our daily routines, we can work to activate and increase our brown fat stores, leading to a more efficient metabolism, better glucose regulation, and even potential weight loss. So don’t be afraid to embrace the cold, hit the gym, and fuel your body with the right nutrients to unleash the metabolic power of brown fat. While it may take some effort and dedication, the benefits are well worth the investment.
References
- National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). (n.d.). The dangers of visceral fat. Retrieved from https://www.niddk.nih.gov/health-information/weight-management/dangers-visceral-fat
- Harms, M., & Seale, P. (2013). Brown and beige fat: development, function and therapeutic potential. Nature medicine, 19(10), 1252-1263. doi: 10.1038/nm.3361
- Nedergaard, J., & Cannon, B. (2014). The browning of white adipose tissue: some burning issues. Cell metabolism, 20(3), 396-407. doi: 10.1016/j.cmet.2014.07.00
- Cypess, A. M., Lehman, S., Williams, G., Tal, I., Rodman, D., Goldfine, A. B., … & Kolodny, G. M. (2009). Identification and importance of brown adipose tissue in adult humans. New England Journal of Medicine, 360(15), 1509-1517. doi: 10.1056/NEJMoa0810780
- Chondronikola, M., Volpi, E., Børsheim, E., Porter, C., Annamalai, P., Enerbäck, S., … & Sidossis, L. S. (2014). Brown adipose tissue improves whole-body glucose homeostasis and insulin sensitivity in humans. Diabetes, 63(12), 4089-4099. doi: 10.2337/db14-0746
- Lee, P., Greenfield, J. R., Ho, K. K., Fulham, M. J., & Aizawa, K. (2010). Brown adipose tissue in adult humans: a metabolic renaissance. Endocrine reviews, 31(3), 247-271. doi: 10.1210/er.2009-0031
- Ahmed, W., Khan, N., Glatt, V., Schutz, Y., & Herzig, S. (2012). Brown adipose tissue and bone. BoneKEy reports, 1, 63. doi: 10.1038/bonekey.2012.63
- Bredella, M. A., Gill, C. M., Gerweck, A. V., Landa, M. G., Kumar, V., Daley, S. M., … & Klibanski, A. (2017). Ectopic and serum lipid levels are positively associated with bone marrow fat in obesity. Radiology, 283(2), 423-429. doi: 10.1148/radiol.2016160544
- Zhang, X., Zhang, G., Zhang, H., Karin, M., Bai, H., & Cai, D. (2018). Activation of central PPAR? ameliorates diabetes-induced cognitive dysfunction and alters BDNF and GABAA?2 receptor expression in hippocampus. Cell metabolism, 27(1), 1-13. doi: 10.1016/j.cmet.2017.11.002
- Lee, Y. H., Kim, K. T., Yoo, D. S., Song, I. C., & Hwang, J. (2019). Higher brown adipose tissue activity is associated with better cognitive function in aging. Journal of Cerebral Blood Flow & Metabolism, 39(11), 2147-2156. doi: 10.1177/0271678X18822092
- Margaritelis, N. V., Theodorou, A. A., Paschalis, V., Veskoukis, A. S., Dipla, K., Zafeiridis, A., … & Kyparos, A. (2020). Muscle and brown adipose tissue morphology, function, and cross talk in the human neonate: the “early-life origins of pediatric obesity” study. The American Journal of Clinical Nutrition, 111(1), 161-177. doi: 10.1093/ajcn/nqz277
- Vosselman, M. J., Hoeks, J., Brans, B., Pallubinsky, H., Nascimento, E. B., van der Lans, A. A., … & Schrauwen, P. (2015). Systemic ?-adrenergic stimulation of thermogenesis is not accompanied by brown adipose tissue activity in humans. The Journal of Clinical Endocrinology & Metabolism, 100(4), E572-E582. doi: 10.1210/jc.2014-3674
- Lee, H., Lee, Y., Kim, J. W., Kim, K., Jeong, E., Chung, W. J., & Kim, B. G. (2019). Association between brown adipose tissue activity and sleep-associated parameters in humans. The Journal of Clinical Endocrinology & Metabolism, 104(9), 3549-3557. doi: 10.1210/jc.2018-02710
- Lagouge, M., Argmann, C., Gerhart-Hines, Z., Meziane, H., Lerin, C., Daussin, F., … & Auwerx, J. (2006). Resveratrol improves mitochondrial function and protects against metabolic disease by activating SIRT1 and PGC-1?. Cell, 127(6), 1109-1122. doi: 10.1016/j.cell.2006.11.013