Leptin Resistance

By Dr. Joline Fernandes

Leptin is a hormone secreted by adipocytes (fat cells) that regulates appetite and is a key factor in the development of obesity which is a serious social, economic and medical problem in modern society. It travels through the bloodstream to reach the brain. Leptin and its receptors are responsible for regulating the energy homeostasis and body weight as it signals the body that it is full. Leptin level in the body is inversely related to the body weight that is, if the concentration of leptin increases the body weight decreases.

In obesity there is an increase in the leptin concentration in the body but its efficacy is decreased. This is due resistance that is developed in the intracellular leptin receptors or it can also be associated with the decrease in the leptin transport across the blood brain barrier. It is suggested that elevation of C- reactive protein can interfere with the signal transduction pathway of leptin activation. Obesity and chronic consumption of high fat diet can induce changes in the level of transporters and integrity of the blood brain barrier as well as the different regions of the neuronal populations with high metabolic demands such as the hippocampus. In obesity when the adiposity increases the level of leptin released in the blood stream also increases, this can lead to resistance at the level of blood brain barrier transporters. This can lead to less amounts of leptin to reach the brain thereby leading to a reduction in the activation of signalling pathway for food intake and body weight reduction.

Recent studies have shown that leptin also has a direct effect on dopamine which can affect the neural function and behaviour. It is said to influence the reward behaviour via the alteration in the function of dopamine pathway. People with reduced levels of leptin in the body show hyperactivated region in the brain in response to food images. Regulated leptin secretion may suppress this hyperactivity leading to a feeling of fullness and reduced food preferences.

Leptin resistance can be reversed and regulated through lifestyle changes, dietary interventions and behavioural modulation. Our lifestyle plays an important role in regulating the physiological functions of our body. The quality of sleep, our activity levels throughout the day and the type of food we eat helps in these regulations. Keeping all of this in mind we also need to focus on our behaviour toward food.

The choices we make when it comes to food are very important. In the earlier simpler times food choices were mainly focused on nurturing the body and tending to our physiological needs. Through this seasonal changes in the diet and traditional recipes were made. Whereas in today's fast and busy times our schedules are packed and there’s more diversity in our food choices. Now we find foods that are quick to cook and quicker to eat. Eating to nurture our body is considered as laborious and time-consuming. Our thinking and behaviour towards food need to change, we need to understand the importance of our health and its relation to food consumption.