Scratchings-and-Sniffings

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Bad Fat and Its Effect on Health Posted: 08 Sep 2009 07:20 AM PDT OK, I know fat has a purpose. It is the bodies energy depot and it helps insulate our internal organs, supplies essential fatty acids and without it we'd be toast. However, in excess, white fat is unhealthy and new research gives us even more reasons to be mindful of the health ramifications of obesity. In the last post we discussed the potential benefits of activating brown fat. Brown fat probably has a role in keeping us lean by burning white fat to produce heat. That would help us stay lean but there are other reasons to be concerned with excess white fat.   We used to think of white fat as simply the bodies energy store. Some people and pets had more than others in large part due to evolutionary survival mechanisms gone awry in an age of easy access to cheap calories. We know now that white fat has other metabolic activities that contribute to disease. White fat is now thought to be a secretory organ responsible for the production of a number of biologically active chemicals know as adipokines. These chemical mediators produced by fat cells called adipocytes have far reaching effects on the body.    Adipokines are made up of different molecules with diverse functions. These include pro-inflammatory cytokines like interleukin 6 (IL-6) and tumor necrosis factor-alpha (TNF-a); hormones like leptin and adiponectin and other biologically active proteins.   Leptin is an important hormone that effects both appetite and energy expenditure. Obese dogs have up to five times the normal blood levels of leptin, and high levels of leptin actually perpetuate obesity due to a phenomenon called leptin resistance. The hypothalamus no longer responds to persistently high levels of leptin and appetite is not suppressed nor is there a leptin induced increase in energy expenditure in the face of excess calorie intake. Obesity becomes self perpetuating in this case. No wonder it's so tough for animals to lose weight.   Another hormone produced by adipocytes, called adiponectin, is a problem, too. The production of  adiponectin decreases with obesity and since its normal role is both anti-inflammatory and involves regulating insulin sensitivity, too little adiponectin results in greater insulin resistance and more inflammation. This can lead to type two diabetes complications and an increase in inflammation.   Finally, obesity results in increased levels of the pro-inflammatory cytokines TNF-a and IL-6 leading to a chronic state of whole body inflammation. Current theory suggests that a chronic inflammatory state is responsible for a host of chronic disease conditions.    What this all means is that obesity is much more of a disease state than we previously thought. It's not just carrying around extra weight, which causes its own set of problems. Instead, it is a metabolic disease that demands treatment.   But, as we've discussed before, obesity is very difficult to manage with simple diet and exercise. That's why this body of research on the function of both brown and white fat is so intriguing. If we could turn things around by increasing the amount and metabolic activity of brown fat we could reduce the levels of white fat and all the bad stuff white fat secretes.   Don't give up until then. Veterinarians have programs that include diet, exercise and new appetite control drugs that can be effective, with diligence. And considering what we now know about the role obesity plays in the development of chronic disease, diligence is required.

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