I suppose everybody knows about the fact that excess amount of fatty tissue fosters development of many dangerous diseases. However, there aren't many people who realize why it is like that. Even less people know the reason why the visceral fat (i.e. stored inside the abdominal cavity) is the most threatening for health. In this article I will explain these dependencies.
Get to know your fat
Although, majority of our enery reserves is stored in subcutaneous fatty tissue, some amount of spare fat is also gathered in other places of human body, which are:
within inner organs (visceral fat),
around mammary glands,
around sex organs,
From the aesthetics point of view, subcutaneous fat seems to be the biggest problem. First of all, because it is visible (it forms characteristic folds), second of all – because there's a lot of it. However, you should pay attention to the fact, that from the metabolic point of view, the biggest threat is visceral fat.
How is it possible that one kind of fatty tissue is more dangerous than the other?
The assumption stating that the location of fatty tissue is the factor which differenciates its influence on the body will seem ridiculous for as long, as we will not take under consideration the fact that adipocytes – apart from storing energy – also have endocrine functions. It means that they excrete various substances, which influence functioning of the whole body. But this influence is sometimes adverse...
Scientific studies show, that visceral fat is the most active metabolically and that it excretes the biggest amount of substances, which are deadly for health.
But what's about visceral fat?
It is proven scientifically, that, along with the increase of the amount of visceral fatty tissue, the risk of the following diseases rises dramatically:
high blood pressure,
It can be concluded, that visceral fat produces large amount of pro-inflammatory adipokines, which strengthen insulin resistance, such as:
plasminogen activator inhibitor type 1 (PAI-1),
tumor necrosis factor (TNF-alpha),
The substances mentioned above are highly active biologically and they influence various tissues and organs. Some of them stimulate the development of atherosclerotic plaque, other disturb the functions of vascular endothelium, which fosters high blood pressure, another group disorders the activity of insulin and lead to insulin resistance, what contributes to deregulating metabolism.
Toxic fatty acids
Apart from vatious kinds of adipokines, visceral fat releases large amount of free fatty acids (FFA) to blood. During physical effort and negative energy balance, such phenomenon is desirable, but in other situations it may be the source of problems. Too big amount of free fatty acids within liver increases the synthesis of triacylglicerols and apolipoprotein-B. It may foster developing fatty liver. Within muscle tissue, FFA disturb the activity of insulin signal pathway, which is why muscles catch blood glucose worse. This, once again, fosters hyperglycemia and, as a result – compensatory hyperinsulinemia. It also makes it harder to burn spare fat. That's how the vicious circle closes.
Visceral fat and cortisol
Although not everybody knows that, the fact is that within visceral fatty tissue, there is the hydroxysteroid dehydrogenase enzyme type 1 (11b-HSD 1). It has the ability of transferring the biologically inactive cortison into... cortisol. The result of the increase of visceral fat is, therefore, higher amount of active glucocotricoid, which leads, among others, to worsening the insulin resistance. The influence of cortisol is mainly local (which does not belittle the negative consequences of such state), but in extreme cases it may also be systemic.
At the end a curiosity: men as a target
That's bad news for men, because they are the ones who are especially threatened with the increase of visceral fat. It is connected with higher activity of a hormone, called lipoprotein lipase (LPL), within visceral fatty tissue, which stimulates the decomposition of chylomicrons and it increases the capture of fatty acids by its cells. In case of women, the activity of LPL is higher in subcutaneous tissue located within hips, buttocks and thighs. Therefore, taking under consideration the influence of visceral fat on the risk of development of type 2 diabetes and circulatory system diseases, men should stay cautious and pay attention to the quality and quantity of the consumed food.