We all know that having lots of belly fat is bad. We are told that it increases the risk of cardiovascular disease, diabetes and a range of other health problems. But why is belly fat bad?
There are number of reasons but I will explain one of the major ones. This has to do with belly fat becoming a source of inflammation in the body, and stimulating atherosclerosis, causing insulin resistance etc. This post is a bit long, since first there is an explanation of the players and their function.
The type of cell that stores fat is called an adipocytes. These cells play a valuable role in our bodies. They store fat for later use as an energy source. Adipocytes also provide cushioning to the organs and the body in general. An example of cushioning, since feet are in my mind from the last post Going barefoot to save aging joints, is the fat pad under the heel to provide cushioning when the heel comes down on the ground.
Adipocytes will transport fat through their membranes and store it. If there a continual energy imbalance with more energy being consumed in the diet than is being used by the body, the adipocytes will keep taking up more and more fat. The adipocytes get bigger and bigger, and the fat layers and the belly get bigger and bigger.
In the belly as it grows it attracts lots of macrophages, which are one type of white blood cell. Macrophages circulate in the blood and are found throughout all tissues. One of the roles of macrophages is digestion (phagocytosis) of invading organisms, such as bacteria, and to clean up the bits of damaged cells. They are also involved in inflammatory responses. As an example, you have a scratch that is infected. As part of your body’s response to the “threat”, macrophages will congregate in the area help with removal of the bacteria, and be involved in triggering inflammation in the area, which gets red, swollen and sore.
When adipocytes get very full of fat some of them will start to die. The macrophages then start to remove the cell bits. When they are actively removing bits they send out some chemical signals which attract more macrophages to the feast. The fat that is released from the adipocytes triggers the macrophages to start to put more chemical signals that trigger inflammation, and stimulate other cells of the immune system.
This then means that your belly fat is releasing inflammatory chemical signals into the rest of the body. The whole body becomes slightly inflamed.
Atherosclerosis (narrowing of the arteries), once it has started to develop, is somewhat similar, in that it involves fat buildup and immune cells have gone into overdrive in the artery walls. The immune cells send out inflammatory signals, which attract more immune cells and so atherosclerosis develops.
If as atherosclerosis is developing and the body is already in a heightened state of inflammation due to the belly fat, the rate of blocking of the arteries may increase. Additionally, in areas where there is the potential for atherosclerosis to start, the inflammatory signaling from the belly may tip the balance for atherosclerosis starting to develop.
To sum up. A large belly can result in inflammation throughout the body, which increases the risk of cardiovascular disease due to increasing the level and rate of development of atherosclerosis.
I was going to talk about diabetes too, but this is too long already. I will save it for another day.
photo credit: daniel.julia
