Dr. Kwang Yang, Family Medicine
The increasing global prevalence of obesity is recognized as a risk factor for the development of various diseases, and there is a growing research on the role of fat or adipose tissue in obesity and type 2 diabetes. Studies revealed that stimulation of brown adipose tissue activity and the browning of white adipose tissue play a significant role in controlling energy homeostasis and insulin sensitivity leading to multiple health benefits especially preventing obesity and type 2 diabetes (T2D).
There are two main types of adipose tissue in our body, namely brown fat and white fats. The metabolically active brown fat is considered the good fat due to its ability to produce more calories to be used for body heat. White fat is the type of fat that most people try to avoid accumulating as it forms a surplus of calories. White fat cells store energy in the form of a single large, oily droplet, and it does little to be burnt to produce calories like brown fat does.
This article focuses on the properties of brown fat, its associated health benefits in preventing obesity and type-2 diabetes in the general population, and different ways to increase it.
What is brown fat?
Brown fat is a specialized for of adipose tissue in humans and other mammals that is located mainly around the neck and large blood vessels of the thorax. Other common locations include upper back between the shoulder blades and along the sides of upper spine. The energy in brown fat is released as heat rather than being used to generate ATP. This thermogenic process is vital in newborns exposed to cold as they use this thermogenesis process to maintain good body temperature, as they are unable to shiver, or take other actions to keep themselves warm. Moreover, unlike white fat, which is used to store any excess calories in people, brown fat actually burns calories to produce heat. When fully activated, brown fat generates three hundreds times more heat than any other tissues in the body.
What are the benefits of brown fat?
Brown fats play important roles in controlling body weight and body heat and preventing diabetes, as well as increasing body's metabolic set point. Certain studies have shown that by increasing brown fat purposefully in obese or overweight adults may reduce excess stores of white fat naturally. A certain protein in brown fat appears to enhance the metabolism of white fat, and people lacking this protein expended less energy, gained weight and developed diabetes. Brown fat has also been shown to be one of the tissues in the adult body that can be stimulated to use the highest amounts of glucose per gram, helping to control blood sugar levels; it has unique diabetes-fighting properties. People with lower glucose levels tend to have more brown fat than those with higher levels, which indicates that it may play a direct role in glucose control. Moreover, individuals had brown fat transplanted onto their abdomen after eight weeks were not only leaner than a placebo group, but also processed blood glucose better and had reduced insulin resistance.
Furthermore, Brown fat can increase individuals’ metabolic set point. This set point is the degree of body weight at which the brain begins to slow metabolic activity automatically, making it more difficult to lose additional weight. Brown fat helps to combat this metabolic slowdown. For example, if someone is able to burn an extra amount of 200 calories a day through their brown fat, that’s enough to shed a pound of body fat in just a couple of weeks. The calorie-burning boost from brown fat could be enough to reverse this weight gain of about 10 pounds of weight per decade and help older individuals maintain the body fat they had as young adults. Thus, brown fat prevents obesity and decreases an individual's risk of getting type-2 diabetes.
How to gain brown fat?
Expose skin to cold temperature will signal the brain to stimulate body' brown fat activity by acting on vascular system directly to increase blood flow to brown fat stores and by sending nerve impulses to brown fat cells to stimulate cellular activity. Researchers have found that sitting in a 59°F room for two hours wearing summer clothing will stimulate brown fat to burn an extra 100 to 250 calories, depending on the individual. Additionally, a temperature of 66°F triggers brown fat activation and lowering thermostat to the mid-60s or below may be enough to stimulate at least some brown fat activity.
Moreover, exercise in cool temperature at 62°F to 64°F or lower helps to stimulate brown fat stores, especially if skin is exposed. In addition, eating a low-fat, high-carb diet along with more un-peeled apples will increase and boost brown fat activity. Ursolic acid—a substance that occurs in high concentrations in apple peels—increases brown fat and muscle mass, while at the same time reducing obesity and improving glucose tolerance. Other foods containing ursolic acid include blueberries, cranberries, plums, and prunes, holy basil, bilberry, peppermint leaves, periwinkle, and hawthorn.
Reducing white fat accumulation by eating the right dietary fats:
The key to a healthy cholesterol profile and prevention of obesity and type-2 diabetes is to maximize amount of brown fat and reduce amount of white fat. This section focuses on ways to obtain beneficial dietary fat to reduce amount of white fat. In terms of dietary fats, the worst type is trans fat in foods such as cookies, French fries, and pastries. They increase amount of harmful LDL cholesterol in bloodstream and reduced the beneficial HDL cholesterol. Trans fat creates inflammation, which is directly linked to diabetes and other chronic conditions because they contribute to insulin resistance increasing the risk of developing type 2 diabetes. Fats from vegetables, nuts, seeds and fish are good dietary fat as they differ from trans fat by having fewer hydrogen atoms bonded to their carbon chains. They are liquid at room temperature, not solid. Good sources of beneficial fats are olive oil, peanut oil, canola oil, avocados, and most nuts, as well as high-oleic safflower, corn and sunflower oils. Eating food with beneficial fats reduces harmful LDL cholesterol and improves the cholesterol profile. It also lowers triglycerides and thus preventing obesity and risk of getting type-2 diabetes
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Scheideler M, Herzig S, Georgiadi A. Endocrine and autocrine/paracrine modulators of brown adipose tissue mass and activity as novel therapeutic strategies against obesity and type 2 diabetes. Hormone molecular biology and clinical investigation. Aug 29 2017;31(2). doi: 10.1515/hmbci-2017-0043.
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