For patients struggling with obesity and weight, hormones often affect their overall health. Excess body fat can cause problems with weight and hormonal issues. Leptin is one of the hormones directly connected to body fat and obesity.
Leptin, a hormone released from the fat cells located in adipose tissues, sends signals to the hypothalamus in the brain. This particular hormone helps regulate and alter long-term food intake and energy expenditure, not just from one meal to the next. The primary design of leptin is to help the body maintain its weight.
Because it comes from fat cells, leptin amounts are directly connected to an individual's amount of body fat. If the individual adds body fat, leptin levels will increase. If an individual lowers body fat percentages, the leptin will decrease as well.
Leptin is sometimes called the satiety hormone. It helps inhibit hunger and regulate energy balance, so the body does not trigger hunger responses when it does not need energy. However, when levels of the hormone fall, which happens when an individual loses weight, the lower levels can trigger huge increases in appetite and food cravings. This, in turn, can make weight loss more difficult.
When the body is functioning properly, excess fat cells will produce leptin, which will trigger the hypothalamus to lower the appetite, allowing the body to dip into the fat stores to feed itself. Unfortunately, when someone is obese, that individual will have too much leptin in the blood. This can cause a lack of sensitivity to the hormone, a condition known as leptin resistance. Because the individual keeps eating, the fat cells produce more leptin to signal the feeling of satiety, leading to increased leptin levels.
Low levels of leptin are rare, but can occasionally occur. For a few patients, a condition known as congenital leptin deficiency keeps the body from producing leptin. Without leptin, the body thinks it has no body fat, and this signals intense, uncontrolled hunger and food intake. This often manifests in severe childhood obesity and delayed puberty. The treatment for leptin deficiency is leptin injections.