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Insulin and Leptin

Dr. Karol M.D Article by: Dr. Karol M.D
Date: Jan 27, 2014 · Posted in: Metabolism, Weight Management
Insulin and Leptin
Insulin and Leptin.

The reason why I decided to write a blog on these two hormones is because they are perhaps the most important hormones regulating fat stores, blood glucose and appetite. As such they are also the most important hormones regulating body weight. Since such is the theme of this month then it goes without saying that these two hormones must not be omitted in the discussion on the topic.

Let’s start with Insulin. Basically it’s a hormone that makes our body store glucose and fat when there is an abundance of food.  Shortly after a meal, when the food particles are being absorbed into the blood stream, glucose (which is the primary carbohydrate utilized by the body for energy) travels to the organ called the pancreas. The pancreas plays two primary roles. It releases insulin due to a rising glucose concentration and it also releases digestive enzymes into the small intestine for the digestion of food before being absorbed into the blood stream. 

The primary role of insulin is to get rid of the high sugar circulating in the blood. It does this by acting on three primary tissues, muscle, fat, and liver. The reason it does this is two fold. First a high concentration of glucose is toxic to blood vessels. This is precisely why in diabetes (where there is insufficient Insulin or there is resistance to Insulin) the primary problem is the damage to blood vessels by a high glucose. The other reason is to absorb the glucose into muscle as an energy source, into fat to be converted to fat for storage, and to the liver to be stored for future use in the form of glycogen (these are glucose molecules connected together for a more optimal storage).

The problem arises when someone is consuming excessive amounts of simple sugars. Examples are sweets, chocolate, table sugar, pop, white pasta, white rice, and sweet juices packed with sugar. These simple sugars cause excessive release and spikes of insulin which eventually lead to insulin resistance and type 2 diabetes. In such a case there is too much glucose in blood vessels and these channels of life get destroyed. The consequence: heart attacks, strokes, permanent kidney damage, blindness, diabetic food and polyneuropathy (damage to nerves).

The significance of this is that although it is not directly related to weight loss for esthetic reasons it does illustrate the importance of maintaining a healthy body weight.

So what about Leptin? Well this is a very interesting and recently discovered molecule. It is a hormone released by fat tissue that regulates appetite by acting directly on the region of the brain called the Hypothalamus. Right after a meal Leptin is released, which inhibits appetite and further food intake. Furthermore the more fat tissue there is, the more Leptin circulates in our blood.  Thus Leptin concentration is directly correlated to the amount of fat stored. Theoretically this should mean that the more weight one has in the form of fat the less of an appetite one should have due to the higher levels of Leptin. Unfortunately this is not how it usually works. Similar to type 2 diabetes, when there is an  excessive amount of Leptin for a prolonged period of time, the brain becomes desensitized to the inhibitory effect of Leptin. The consequence is that although a person may have excessive stores of fat, the appetite is not inhibited like it should, and the person continues to consume excessive calories, which just perpetuates the problem. It is only when the body weight is optimal or close to being optimal that Leptin fulfils its role fully by being a strong appetite suppressant. In other words, the more excessive body weight one has, the harder it will be to lose it. This is yet another reason why having a healthy body weight is important.

For those of you who may be interested in supplements which can increase Leptin levels, Vitarock does carry a product called African Mango extract, which does increase Leptin levels and in this way inhibits appetite.