View Full Version : Leptin: The Fat Burning Hormone

10-14-08, 10:22 AM
Mandy Mercante, Health Newswriter, Summerville, SC | September 14, 2008

Have you tried every diet out there and still can’t get the weight off? If so, there may be a hormone to blame. Many people are beginning to learn about hormones and the key role they play in weight loss. Not every diet is right for every person and hormones play a major role in deciding what diet is best for each person.
One crucial way to customize an individual’s diet is to measure an important hormone called leptin. Leptin actually “tells” the brain to burn fat. If your brain doesn’t receive the message from leptin, then your body will not be able to burn fat for energy. Simply put, you will not lose weight no matter what you eat.

Leptin is synthesized and secreted primarily by adipocytes (fat cells). It is present in blood serum in direct proportion to the amount of adipose (fat) tissue and as fat cells become enlarged in obesity, they secrete more leptin. This important hormone communicates with the central nervous system to regulate energy intake and energy stores in the body so that the hypothalamus can efficiently maintain a stable body weight.

Leptin receptors are present in tissues throughout the body, suggesting that it can have direct effects on other aspects of health. Leptin helps regulate immunity, maintain healthy blood pressure levels, and support cognitive function. In addition, women with premenstrual syndrome have been found to have overly high levels of this hormone, as do individuals with hypothyroidism.

Clearly, leptin is of interest in a wide range of conditions, and may be one of the most important hormones in the human body. Consequently, one would think that it would be desirable to increase leptin levels. However, in most overweight people, leptin levels are actually excessively high due to leptin resistance, a process similar to the concept of insulin resistance.

To understand why this is so, we must look at the way a normal weight body is designed to communicate. The process begins when the brain notes the amount of leptin secreted by fat cells. If the brain determines these leptin levels are normal, it shuts off the signal to store extra calories as fat. The body no longer feels like eating because the brain, with the help of leptin, has given the full signal.

When our ancestors experienced decreased food supply, calories stored as fat were broken down and used as fuel. This caused leptin levels to decline and metabolism to decrease to adjust to the decreased food supply. When food supply once again increased, so too did leptin levels. Once the hunter/gatherer humans had replenished their reserves, leptin signaled our ancestors to stop eating.

In today’s society, however, food surrounds us and overeating is common. This disrupts the hormonal signals in our bodies. Eventually, leptin receptors become desensitized to leptin’s effects. Once a person becomes leptin resistant, the body has a difficult time transporting leptin past the blood brain barrier to the hypothalamus where it is needed to send satiety signals. Even though blood levels of leptin may be excessively high, brain levels are insufficiently low, resulting in food cravings and weight gain. The brain believes the body is in a famished state and tells it to continue to store fat.

So, how can we control our levels of leptin? Sufficient sleep is one of the most important factors in controlling leptin. Like melatonin, leptin is secreted in the highest amounts at night, and in human subjects deprived of sleep the timing of the leptin secretion peak occurred earlier, disrupting hormonal profiles and encouraging weight gain.

Avoiding sugar and bad fats and instituting a daily exercise regimen also can help to a certain extent. However, research has shown that when engaged in a weight loss program, obese subjects aren’t as efficient at reducing leptin levels as normal weight subjects. When morbidly obese and lean females went on a 24-hour fast, serum leptin levels decreased by only 20 percent in obese subjects compared to 62 percent in lean subjects, even though the obese subjects did lose some of their body mass index.

Leptin is emerging as a hormone that is integral to weight management. While lifestyle factors are important in controlling leptin levels, to achieve weight loss, individuals may need to turn to leptin-lowering supplements. Scientists have found that a number of nutritional supplements can reduce levels of this including melatonin (http://www.alignlife.com/page/v1yhzhsn.html), L-carnitine (http://www.alignlife.com/page/3sei737a.html) and omega-3 fatty acids (http://www.alignlife.com/page/caym16mb.html).

So, if you are one of millions who is always on a new diet and nothing seems to work, you may need to have your leptin levels checked. What do you have to lose besides the weight???


10-23-11, 12:52 PM
Mellow, how are leptin levels checked? Through blood? Saliva?

10-23-11, 12:59 PM
Mellow, how are leptin levels checked? Through blood? Saliva?
It is a blood test. However good luck finding someone willing to do it. You will probably have to pay yourself. I have no idea where you would find out how/where to get tested though.

10-23-11, 01:42 PM
Let's hear a very weak "Hooray" for the insurance companies.