What Is Leptin?
Among the many pieces of research that attract the most attention of scientists on the issue of obesity, figure the study of digestive hormones secreted by neurons: leptin. It is surely the most intriguing molecule of the lot. Also known as “satiety hormone”, this protein is closely related to the function of regulating fat stores in our body. It also regulates the appetite and modulates the hunger sensation.
A hormone is a protein that plays a messenger role. Once released into the bloodstream, leptin acts on the hypothalamus to transmit its satiety message to specific receptors. In overweight people, the signals emitted by this message never seem to reach the brain, even though they have high levels of leptin. This is known as leptin resistance.
This discovery alone, supported by the explanations of Dr. Bruno Fève, endocrinologist at the Saint-Antoine Hospital in Paris, has given new direction to research in the field of endocrinology.
It is now known that the secretion of leptin evolves in a circadian rhythm (1). The leptin level is normally low in the morning (which makes you want to eat). It reaches a high threshold in the evening (which is at the origin of the feeling of satiety). The lowest level is around noon. The highest leptin level is observed in principle after midnight.
The relationship between leptin and obesity?
A very recent scientific study (3) on the control of appetite and the regulation of body weight brings quite precise answers to the question. It is led by scientists David Sunter, Donal O’Shea and Stephen R Bloom of the endocrine unit of the renowned Imperial College School of Medicine, Hammersmith Hospital, London, UK.
On a simple scale, remember that obesity (4) results from a state of significant imbalance between excessive energy intake (through food) and insufficient caloric expenditure. This situation results in an effect of overweight, obesity, due to excessive expansion of adipose tissue. At this point, leptin transmits a signal to our hypothalamus. This one informs on the state of the reserves of the adipose tissue, in order to make us able to limit our food intake. It is therefore a fairly specific hormone, useful for the interpretation of our eating behavior.
Why sometimes or all the time, do we feel a voracity vis-à-vis food? And why in other circumstances, we feel sated.
For a high rate of leptin, our brain is educated on our state of satiety. Leptin associates with certain sensors in the hypothalamus and stimulates the release of chemical messages of appetite suppressant. People who have difficulty connecting with leptin therefore have eating disorders. As a result, they feed uncontrollably. Consequence: an overweight or obesity can appear and settle permanently.
What is leptin resistance?
One would think that with the large amount of leptin they produce, obese people would have a facility to stop eating and thus lose weight. Unfortunately, it is as with insulin a problem of resistance to leptin.
If the amount of leptin remains high enough, our leptin sensors become insensitive to the hormone over time (5). We can then develop what is called “resistance to leptin”. In this case, despite the excess of fat, and the rather important secretion of leptin to say stop storage, its message will have no influence: no decrease in appetite and no increase in metabolism.
The person is constantly feeding because the appetite does not weaken, increasing the amount of fat stored. Too much fat causes an even deeper disturbance in leptin transmissions. Having become resistant to leptin, the brain continues to activate the feeling of hunger, which makes you want to eat more. This is the vicious circle of obesity! Leptitox will help you with that.