For a long time Leptin was regarded as the bearer of hope in the fight against obesity. Because the hormone curbs the appetite. However, many obese people have high leptin levels in their blood. Find out more about the relationship between leptin and our body weight here.
What is leptin?
Leptin is a hormone that is mainly produced by the fat cells of the body. It plays a role in the feeling of hunger and has therefore been the subject of research for some time.
The hormone leptin is a natural appetite suppressant and is mainly produced by the fat cells (adipocytes). But also in the bone marrow, skeletal muscle, gastric mucosa, breast cells and parts of the brain, leptin is produced. When the fat cells are well filled, they send leptin out and give the signal "We are full!".
The exact regulation of food intake is still not fully understood. Even under what conditions leptin leads to an increase or decrease in weight is still unclear.
The effect of leptin
Leptin exerts its effect via two different docking sites (receptors) in the hypothalamus. This part of the diencephalon is an important center of control for the involuntary nervous system (vegetative nervous system) and produces various hormones.
After its connection with one type of receptor, leptin leads to a release of further appetite suppressing hormones or, after connection with the other type of receptors, to an inhibition of the release of appetite-stimulating hormones.
Ultimately, it slows down our appetite. Through this mechanism, leptin is seen as an antagonist of the hormone ghrelin, which promotes the feeling of hunger.
Metabolism of leptin
Furthermore, leptin should be in direct interaction with the sugar regulator hormone insulin. It has been shown that leptin can stimulate glucose utilization (sugar utilization) in diabetes patients, irrespective of insulin.
Therefore, leptin is considered a potential alternative to insulin therapy in people with type 1 diabetes mellitus. Side effects of insulin would be eliminated. Clinical studies on this topic should provide safe insights (Leptin therapy in insulin-deficient type I diabetes, MY Wang et al).
In addition, leptin leads to a blood pressure increase, a heart rate increase and to stimulate the development of heat in the cells.
Another effect of a high leptin level in the blood should be the braking of the urge to move. Anyone who has many leptin hormones in their blood, therefore, has less desire to move.
The role of leptin in losing weight
For some time leptin has been considered a potential appetite suppressant in the treatment of obesity. However, it has been found that the majority of overweight patients have very high levels of the hormone in their blood.
The cause is probably a leptin resistance, whereby the effect of leptin on its receptors is absent. Although blood leptin levels are high, the brain does not feel satiated. Rather, the feeling of hunger persists and food intake continues.
Some researchers believe that leptin resistance is the cause of obesity. However, the exact metabolic processes have not been fully investigated and the development of obesity is dependent on many factors, according to current knowledge.
Diet and leptin
Certain foods - especially very sugary and fatty foods, such as fried and caramelized food - cause inflammation in the brain and leptin can not work. There is currently no proven evidence, but one cause of leptin resistance seems to be the eating behavior.
In addition to leptin resistance, there are still genetic diseases that can lead to pathological obesity. By mutating genes that produce proteins for the leptin pathway, their function is disturbed. The effect is similar to leptin resistance - sufferers have a disturbed satiety. However, such genetic defects are rarely the reason for obesity.
Leptin as a drug
People with congenital fat cell depletion (lipodystrophy) are prescribed leptin because they can not produce it themselves. Only for this indication, the drug has been approved in the US since 2014, in Europe, the approval process is still ongoing.
The administration is carried out by the attending physician as an injection into the subcutaneous fatty tissue. In the form of capsules, globules or tablets, the preparation is not available.
Effect against obesity not proven
Due to the effects described leptin is traded as a miracle weapon against obesity. The idea is that taking the drug increases leptin levels and boosts fat burning.
The manufacturer himself points out that weight loss by leptin is not proven. It is therefore strongly advised against using a leptin preparation without prior consultation with a specialist in metabolic diseases (endocrinologist).
Side effects of leptin
If leptin is administered externally, it can lead to serious side effects. The body can produce antivenin (antibodies) against the hormone. This means that the leptin produced by the fat cells can no longer work - the leptin levels are even decreasing instead of increasing.
Furthermore, autoimmune reactions to the liver and kidneys have been described, which can lead to failure of these organs as they progress.