Tag Archives: brown fat

The Paleo Diet Skinny on Fat: White Fat Vs Brown Fat

Fat gets a bad rap. Our societal standards for attractiveness promotes lean body types, leading to eating disorders and body image disturbances for men and women1 alike, leading most people to prefer to have as little body fat as possible.2 Although we know obesity is a huge risk factor for numerous diseases and conditions,3 there’s more to adipose tissue than meets than eye. In fact, body fat isn’t the biggest villain if we maintain healthy levels and stimulate the best kind of it.

Adipose tissue is critical to our survival, and a body without any body fat could lead to decreased fecundity and premature death. 4 Fat has a critical evolutionary function to store calories safely and abundantly so the energy can be used when food is scarce. Adipose tissue is also an insulator to our internal organs and provides cushioning to protect us from the environment, such as having a nice plush landing pad when we fall. Scientists have discovered that stored fat does more than sit around waiting to be used, it also metabolically active – that’s right fat can burn calories. 5

Scientists classify adipose tissue as an endocrine organ6 that releases over 20 different hormones and bioactive substances that control metabolism. For example, adipose tissue produces one form of estrogen, as well as leptin, a hormone that helps regulate appetite and hunger. It also contains receptors for insulin, growth hormone, adrenaline, and cortisol.7 The dysregulation of the bioactive substances, called adipocytokines, contributes directly to obesity-related diseases, such as atherosclerosis and inflammatory conditions. 8

There are two distinct types of adipose tissue found within the body, with completely different functions from one another. White fat, which is the one we normally want to reduce to improve our appearance, and brown fat, which is the beneficial one (we probably didn’t even know about) that we want to create more of.  Brown fat is composed of several small lipid droplets, compared to the white fat’s single lipid droplet, and it contains a large number of iron-containing mitochondria and tiny blood vessels,9 combining to give this fat its brownish color.10 These mitochondria consume fat and glucose11 to produce heat to generate warmth for the body as needed, while also increasing the metabolism12 by oxidizing white fat, and burning calories, without producing much ATP. 13 This activity is similar to how muscle functions compared to that of white fat.

Scientists discovered that lean people tend to have more brown fat than obese people and they are investigating how to increase a person’s brown fat or stimulate it to be more active.  In addition to the benefit of burning white fat, people with higher levels of brown adipose tissue demonstrate an inverse relationship with developing non-alcoholic fatty liver disease.14 When people overeat and under-exercise, they not only increase their total amount of white fat into unhealthy levels, but also it is distributed in a way to leads to metabolic15 and inflammatory diseases.16 Further, this behavior results in brown fat becoming dysfunctional and in turn unable to burn calories. Recent studies on brown adipose tissue have shown that a defect and dysregulation in this tissue is one probable cause of obesity.17

So, how do you boost brown fat generation? Focus on the pillars of your Paleo lifestyle. Regular exercise, adequate high-quality sleep, and consistent exposure to cold temperatures, such as exercising outdoors in cold weather or keeping the heat turned down in your home, have all been shown to contribute to healthy functioning and increased levels of brown fat, meanwhile keeping you white fat in check.18

 

REFERENCES

[1] Thompson, J. Kevin, and Eric Stice. “Thin-ideal internalization: Mounting evidence for a new risk factor for body-image disturbance and eating pathology.” Current directions in psychological science 10.5 (2001): 181-183.

[2] Hellmich, Nanci. “Do thin models warp girls’ body image.” USA Today 26 (2006).

[3] Eckel, Robert H., and Ronald M. Krauss. “American Heart Association call to action: obesity as a major risk factor for coronary heart disease.” Circulation97.21 (1998): 2099-2100.

[4] Moitra, Jaideep, et al. “Life without white fat: a transgenic mouse.” Genes & development 12.20 (1998): 3168-3181.

[5] Addy, Carol, et al. “The acyclic CB1R inverse agonist taranabant mediates weight loss by increasing energy expenditure and decreasing caloric intake.”Cell metabolism 7.1 (2008): 68-78.

[6] Kershaw, Erin E., and Jeffrey S. Flier. “Adipose tissue as an endocrine organ.”The Journal of Clinical Endocrinology & Metabolism 89.6 (2004): 2548-2556.

[7] Kershaw, Erin E., and Jeffrey S. Flier. “Adipose tissue as an endocrine organ.”The Journal of Clinical Endocrinology & Metabolism 89.6 (2004): 2548-2556.

[8] Rosenow, Anja, et al. “Identification of novel human adipocyte secreted proteins by using SGBS cells.” Journal of proteome research 9.10 (2010): 5389-5401.

[9] Bartelt, Alexander, et al. “Brown adipose tissue activity controls triglyceride clearance.” Nature medicine 17.2 (2011): 200-205.

[10] Flatmark, Torgeir, Frank J. Ruzicka, and Helmut Beinert. “The pattern of iron—sulfur centers in brown adipose tissue mitochondria: Preponderance of ETF dehydrogenase and invariance with the thermogenic state.” FEBS letters 63.1 (1976): 51-55.

[11] Ouellet, Véronique, et al. “Brown adipose tissue oxidative metabolism contributes to energy expenditure during acute cold exposure in humans.” The Journal of clinical investigation 122.2 (2012): 545.

[12] Seale, Patrick, et al. “PRDM16 controls a brown fat/skeletal muscle switch.”Nature 454.7207 (2008): 961-967.

[13] Ouellet, Véronique, et al. “Brown adipose tissue oxidative metabolism contributes to energy expenditure during acute cold exposure in humans.” The Journal of clinical investigation 122.2 (2012): 545.

[14] Yilmaz, Y., et al. “Association between the presence of brown adipose tissue and non‐alcoholic fatty liver disease in adult humans.” Alimentary pharmacology & therapeutics 34.3 (2011): 318-323.

[15] Jensen, Michael D. “Role of body fat distribution and the metabolic complications of obesity.” The Journal of Clinical Endocrinology & Metabolism93.11_supplement_1 (2008): s57-s63.

[16] Lovejoy, Jennifer C., Steven R. Smith, and Jennifer C. Rood. “Comparison of Regional Fat Distribution and Health Risk Factors in Middle‐Aged White and African American Women: The Healthy Transitions Study.” Obesity research9.1 (2001): 10-16.

[17] Himms-Hagen, Jean. “Obesity may be due to a malfunctioning of brown fat.”Canadian Medical Association Journal 121.10 (1979): 1361.

[18] Ouellet, Véronique, et al. “Brown adipose tissue oxidative metabolism contributes to energy expenditure during acute cold exposure in humans.” The Journal of clinical investigation 122.2 (2012): 545.

 

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