One type of fat is better to have rather than not. It is brown fat that is good for health because it fights obesity and reduces the risk of chronic diseases such as diabetes, high blood pressure, and heart disease.
White adipose tissue is the cause of so many evils, while brown fat could even be the solution to our health issues, including weight gain and obesity. The contradiction is only apparent.
In a nutshell, the difference between the two types of fat present in our body is the following:
- White fat, which the body stores in much greater quantity, saves energy by storing calories.
- Brown fat burns energy by generating heat, present in large amounts in hibernating animals.
Brown fat tissue has attracted the attention of scientists for its anti-obesity potential. But there is a problem that experts have encountered: brown fat is not readily identifiable because it is found in hidden parts of the human body, especially around the neck and shoulders.
Therefore, it is not easy to recruit people with high levels of brown adipose tissue to assess their health conditions through rigorous testing. A new study in Nature Medicine solved the problem by recruiting participants from patients undergoing a positron emission tomography (PET) scan for cancer diagnosis.
Radiologists performing this test report the presence of brown adipose tissue to make sure they can distinguish it from a tumor. In this way, the scientists were able to evaluate the effects of brown fat on the participants’ health without testing healthy individuals who would have no reason to perform this type of examination.
Overall, 52,000 people were involved. They detected brown adipose tissue in only 10% of the participants. Such a low percentage is probably because people subjected to PET were advised to avoid exposure to the cold, exercise, and caffeine, all activities that increase the production of brown fat.
Brown Fat Test Findings
Characteristics Of Brown Fat Tissue
The role of brown adipocytes is different from that of white adipocytes because they are smaller cells whose dark color is due to cytochromes’ presence in the numerous mitochondria.
Unlike white adipocytes, brown adipocytes do not contain a single large fat mass, but many tiny drops of triglycerides called lipid vacuoles. Consequently, the nucleus and the cytoplasm are not located in the periphery but are distinguishable within the cell.
In addition to a morphological difference, there is also one of a functional nature. While in white adipocytes, the hydrolysis of triglycerides occurs based on the energy requirements of the organism, in brown adipocytes, the degradation of fats happens in response to a lowering of body temperature.
If the body suffers from hypothermia, the brown adipocytes respond by mobilizing their triglycerides, whose catabolism releases energy in the form of heat.
This phenomenon is called shiver-free thermogenesis, to distinguish it from the classic shiver, the involuntary muscle contraction aimed at producing heat we are familiar with.
The brown fat cell, which is the organism’s cell richest in mitochondria, contains a mitochondrial protein called UCP-1 (decoupling protein), which is the fundamental marker of this adipocyte and is involved in thermogenesis.
When a sympathetic stimulus arrives, thanks above all to the B3-adrenergic receptors, the thermogenetic activity is activated.
Mice genetically deprived of these receptors undergo a phenomenon of transdifferentiation of the brown adipose tissue, transforming into white adipose tissue, making them massively obese despite the increased physical activity and the controlled diet.
The brown adipose tissue has a rich sympathetic innervation which makes it particularly sensitive to the activity of catecholamines; hormones secreted rapidly in response to acute psychophysical stress.
When Brown Fat Is Activated
Dietary Factors That Promote The Development And Thermogenesis Of Brown Fat
Brown fat (BAT) is a specialized adipose tissue with a high ability to dissociate cellular respiration from ATP, allowing energy to be stored as heat. Adults have a certain amount of BAT, and its activity is inversely related to adiposity, blood glucose concentration, and insulin sensitivity.
For this reason, a series of studies are underway to increase brown fat in the fight against obesity and diabetes; current knowledge of the possible environmental modifiers of thermogenesis is limited.
In particular, attention is focused on specific phytochemicals like capsaicin, resveratrol, curcumin, green tea, berberine, and fatty acids like fish oil conjugated linoleic acids, outlining the possible mechanisms activated for the conversion of white fat into brown fat.
Curcumin is known to have positive effects on obesity, and integration allows an increase in weight loss and a reduction in the percentage of fat mass and waist circumference. This is possible as specific brown fat markers such as UCP1, Pgc1a, and Prdm16 are activated, which activate the AMPK pathway, although the precise mechanism is still unknown.
There is also an increase in the expression levels of some thermogenesis genes, observing the rise in body temperature in mice exposed to low temperatures for long times in an experimental model. There would appear to be an increase in the content of mitochondria, the powerhouse of the cell.
Gut Hormone And Brown Fat Impact On Satiety
Key Takeaways On Brown Fat
According to the most recent studies, the fatty tissue of mammals (including humans) has the intrinsic ability to transform white adipocytes into brown adipocytes and vice versa.
The brown adipose tissue is not numerically constant in its cell population but expands and shrinks. This event is due to phenomena of hyperplasia and conversion of white adipocytes into brown adipocytes; the coexistence of these cells is conflicting, as the white ones accumulate lipids while the brown ones burn them.
The discovery of these biological mechanisms opens the door to future therapeutic developments in the treatment of obesity; theoretically, to defeat it, it would be sufficient to increase the percentage of brown adipocytes, which is also very useful in the prevention of diabetes.
My name is Jay Fielding. I gained an interest in fitness since I was a child, and eventually developed my passion into a career path. I am now a Certified Personal Trainer with a natural ability to program customized body recomposition and motivate people in achieving their goals, be it gaining muscle or losing fat.