Mar 21, 20213 min read

Is Leptin the Cause of Obesity?

What causes obesity? What happens when Leptin production is abnormal? Would there be a medicine that increases the production of leptin? Read more to find out.

Data from March 2020, the United States ranked #12 in obesity rate, with 36.2% of adults diagnosed with obesity. The leptin gene was first discovered in 1994; this raises questions, could this be affecting weight. Obesity causes huge health problems including, high blood pressure, stroke, heart disease, and mental illnesses. Although many factors contribute to obesity, genetics is one of them. As the human population continues to reproduce, there will be a mutation in the leptin receptor somewhere in the human body's gene. The low production of leptin in the body can be passed down to generation. This happened when both parents carries a copy of the mutated gene.

What is Leptin?

Leptin is a hormone protein in the body. Leptin sends signals to the brain, the hypothalamus, to tell our body that we are full and stop us from overeating. Fat cells release leptin and circulate the blood. It knows how much fat you have eaten as leptin records the amount. However, leptin does not affect how much food you are in taking in the body. It is important to eat every day, as the leptin level will also decrease if you are not eating enough. It should not be ignored as it could lead to severe side effects, including obesity.

What happens when leptin production is abnormal?

A mutation in the LEP gene causes a low-level production of leptin. The LEP gene's job is to make leptin proteins. However, when the LEP gene is mutated, it can cause the production of leptin to be abnormal, meaning no leptin produced or irregular shapes of the proteins. There was research done on mice, one mice had regular leptin, and one was injected to cause a mutation. The recorded data showed that the mice that were injected kept on eating and were marked as obese. The normal mice had a normal weight and were able to eat a normal amount of food. Mutation usually occurs when the RNA is being translated into amino acids. For example, instead of the RNA coding for a stop codon, it codes for a different amino acid which causes a different protein to be made. The melanocortin-4-receptor gene, also known as MC4R, also plays a role in the chemical signals. This gene is found in the brain and receives the chemical signal. It has the ability to turn on or off cells that decreases a person's appetite. MC4R also regulates homeostasis and the energy needed for the body. The melanocortin-4-receptor can also have a mutated gene that affects the production of the MC4R proteins. This mutation happens before transcription occurs; as there are no chemical signals sent to the hypothalamus, there would be a smaller amount of cells. Which results in a smaller amount of DNA and so on.

Another reason leptin production might be irregular is if the person is not consuming enough fat in their body. When there is less fat, there will be fewer fat cells. If you are healthy, your body will have many processes to help your leptin level be regular. One process stimulates the vagus nerve, which is located between the brain and abdomen. When the vagus nerve is notified, you will get hungry, indicating that you need to eat. The vagus nerve's good side effect is that it would take the excess energy and store it in your fat, bringing your leptin level back to normal.

What is Leptin Resistance?

There is a saying that goes if your leptin level is high, it means you are obese, because the brain cannot recognize the chemical signals. Leptin resistance has been compared to be similar to insulin resistance that is found in type 2 diabetes. Lustig described that if your leptin level is low, the food you consume is more rewarding. However people with leptin resistance, this is not a reward because leptin levels will continue to rise.

Would there ever be a supplement to maintain leptin's level?

As of March 2021, there have been leptin supplements that claim to regulate the production. However, there are many arguments if the supplement is effective. It was revealed that leptin supplement does not actually include leptin but nutrients to reduce inflammation. There are many ways that a regular person can increase leptin sensitivity. To name a few: exercising, sleeping, increasing fish intake, and decreasing sugar intake. Do note that there are still ongoing studies on repairing the gene if you have the mutated gene.

Thank you for reading!

Written by Amber Truong

Sources:

Berkheiser, Kaitlyn. “Can Leptin Supplements Help You Lose Weight?” Healthline, 6 Nov. 2018, www.healthline.com/nutrition/leptin-supplements#definition-and-function.

Kam, Katherine. “The Facts on Leptin: FAQ.” WebMD, 17 Mar. 2010, www.webmd.com/diet/obesity/features/the-facts-on-leptin-faq#1.

ProCon.org. “Global Obesity Levels - Obesity - ProCon.Org.” Obesity, 20 Apr. 2020, obesity.procon.org/global-obesity-levels.