Fixing Your Hungry Hormones (Part 2)
By Scott Isaacs M.D.
In my last article, I talked about the fat cell hormone leptin and the effects of leptin resistance. Leptin is a hormone produced by fat cells that is responsible for regulating body weight, appetite, metabolism and our motivation to seek out food. Leptin resistance occurs when this hormone can't get the signal to the brain to shut off appetite. Leptin resistance is a major problem that prevents overweight people from losing weight. By improving leptin resistance, you will be well on your way to losing weight and keeping it off for the long haul.
It turns out that the main cause of leptin resistance is inflammation. What is inflammation? In the most basic terms, inflammation is the body's way of fighting disease, especially infections and cancer. The classic signs of inflammation are redness (rubor), pain (dolor), warmth (calor) and swelling (tumor). Inflammation comes from the Latin inflammare, which literally means to set on fire. Inflammation can be a good thing, without it, you would not be able to fight infections and you would be more susceptible to cancer.
But inflammation has an ugly side as well. Inflammation is the major cause of leptin resistance. Inflammation is also the root cause of insulin resistance, which often leads to elevated blood sugar and type 2 diabetes. Inflammation has also been linked to host of medical problems like heart disease, high blood pressure, strokes, diabetes, bowel disease, liver disease and other medical issues.
There are many causes of inflammation. Infections, medical conditions and stress can all cause inflammation. But it turns out that the major cause of inflammation in the body is excess fat. Yes. The fat in your body causes inflammation. Fat tissue produces substances called inflammatory cytokines that figuratively set fat on fire. The two main cytokines made by fat tissue are known as tumor necrosis factor and interleukin. These agents are the underlying cause of inflammation in the body.
To make things even more interesting, it turns out that fat tissue is comprised of a variety of cells, not just fat cells. Fat cells, indeed are the largest component of fat tissue. They are responsible for storing fat, generating body heat and making leptin as well as many other fat cell hormones like adiponectin, resistin and visfatin. A second cell in fat tissue, called a macrophage is the cell that is primarily responsible for inflammation and making the inflammatory cytokines tumor necrosis factor and interleukin. Macrophages are actually white blood cells, immune system cells that take up residence in fat tissue. When they live in fat tissue, they are called adipose tissue macrophages or ATMs for short.
Today, adipose tissue macrophages are the subject of intense investigation. Scientists have found that these special cells have a lot of special qualities that allow them to produce such high levels of inflammation chemicals. By better understanding the adipose tissue macrophage, scientists hope to unravel some of the complexity behind leptin resistance and ultimately develop new medications to treat obesity and all of the conditions caused by inflammation.