|Two mice; the mouse on the left has more fat stores than the mouse on the right. (Photo credit: Wikipedia)|
Leptin is a small hormone produced by the adipose tissues (fat cells) in our body and functions as a signal for the amount of fat present in the body. Depending on the 'Leptin' signal received, the brain can instruct our stomach to stop demanding food or our mouth to stop eating, thereby reducing food intake. So, in theory, more the amount of leptin in your body, lesser will you eat and it would be a a breeze to keep your weight in control. Of course, there is a catch.
The effect of Leptin was discovered in 1994 in a study involving voraciously eating obese mice. When these mice were given leptin injections, their craving for food dropped and they returned to normal body weight. So, scientists attempted to cure obesity in humans with the help of leptin injections. But, during trials, large amounts and frequent doses of leptin had to be injected to gain significant weight loss in highly obese patients. Also, large doses resulted in redness of skin at the site of injection for certain patients. This side-effect was observed, since leptin is not just a signal for fat content, it also functions as an inflammatory marker, i.e. a hormone that signals an event of an infection or an injury in the body. So, injecting leptin in your body would mean that your body is on a high-alert for some sort of infection/ injury that has not occurred.
Even if you were willing to keep your body on a high alert to lose that excess weight, leptin injections are only likely to work in a small section of the population who are obese due to lack of leptin in their bodies. Majority of obesity cases are caused due to the phenomenon called 'Leptin resistance', where irrespective of the amount of leptin produced by the fat tissue in the body, the brain is not receptive to the leptin signal and does not instruct for reduction in food intake. In such a scenario, any amount of leptin injections would still not be able to promote weight loss in the body. However, if administered, along with amylin (hormone secreted by our pancreas), leptin can help in fat specific weight loss, even in obese people who have developed 'leptin resistance'. So, there is your cure to obesity, the wonder pill for weight loss or that is what the scientists thought at first.
Having discovered leptin less than two decades ago, we know little of leptin and its functions other than signalling the amount fat in our body. As more studies were conducted, we also realized that leptin levels also have an effect of fertility. Higher levels of leptin in the body can result in early menarche in females or at least affect egg quality and outcome of fertilization. So, we cant keep injecting leptin into our bodies to promote weight loss. Since decreasing levels of leptin will increase our appetite, what we really need to do is keep leptin levels in check and there is an extremely safe way to do so. A study has shown that 8 hours of restful sleep can restore your leptin levels in the body to normal. So eat healthy and sleep well to maintain normal leptin levels and stay fit.
- Day 45- The importance of sleep (365daysoffocus.wordpress.com)