Leptin- The Most Powerful and Least Understood Hormone in the Body

Leptin is a master hormone in the human body with wide ranging influence over a multitude of bodily functions. Its discovery in 1994 by researchers investigating the cause of extreme obesity in a certain strain of mice led the researchers to conclude that these mice had a mutation in the gene responsible for leptin synthesis. Because leptin is a powerful appetite suppressor, its absence in the mutant mice led them to eat uncontrollably which caused their obesity. Since then, research on leptin’s effects in the body has exploded, resulting in the publication of thousands of scientific articles in peer-reviewed journals. In addition to influencing weight management, leptin also supports many metabolic functions required for optimum health.

Leptin is a hormone that is produced by fat cells and acts as a lipostat in the body. The more fat a person carries, the more leptin that is produced. Under normal conditions, leptin exists in a free state in the blood, which allows it to cross the blood-brain barrier and effect changes in body functions by binding to receptors on the surface of neurons in a region of the brain called the hypothalamus.

Leptin and Weight Management
Leptin influences a diverse range of metabolic activities in the body. Its primary mechanism of action addresses weight management-related issues. Leptin enhances satiety and appetite control, leading to reduced food intake when fat levels increase in the body. Leptin also results in increased metabolism and thermogenesis by influencing the activity of the thyroid gland, which leads to increased breakdown of stored fat. Leptin’s effect on insulin function supports greater glucose balance which decreases fat deposition after a meal as well as the risk of developing Type II diabetes.

Leptin Resistance Occurs in Overweight People
Many people experience leptin resistance. They are overweight enough to have high levels of leptin in their bodies but are resistant to its effects. The main cause of leptin resistance is high levels of inflammation associated with weight gain. Research has shown that C-reactive protein, a marker of systemic inflammation, actually binds to leptin in the blood and prevents leptin from crossing the blood-brain barrier to reach the brain. Leptin resistant individuals have physiology that resembles that of a starving person. Low leptin functionality results in increased appetite and food cravings, slowed metabolism, and higher levels of serum glucose.

Leptin’s Role in Cardiovascular Health
In addition to its weight management-related effects, leptin positively influences many other health-related factors that are associated with the aging process. This is evidenced by adverse health conditions that occur when people become leptin resistant and have decreased leptin function. Of primary importance is leptin’s effect on cardiovascular health. The heart contains receptors for leptin which influence proper energetic function of the heart when leptin binds to them. Problems with leptin function are a risk factor for the development of cardiovascular disease and also the deposition of fat inside arteries and atherosclerosis. It can also result in blood circulation problems such as high blood pressure because leptin triggers the release of stress hormones that constrict blood vessels. This can strain the heart and also cause kidney problems. Finally, leptin’s role in weight management can influence heart health because even modest weight loss has been found to reduce the risk of a heart attack.

Leptin Benefits Metabolic Health
Leptin is involved in proper platelet function and clotting. People with leptin resistance have an increased chance of stroke because poor leptin function results in greater risk of developing blood clots. Leptin also regulates cholesterol synthesis and other forms of lipid metabolism. In fact, high cholesterol and triglyceride levels often occur in people who are leptin resistant. Because leptin influences insulin function, problems with leptin can result in insulin resistance and Type II diabetes. Leptin also helps to mediate the manufacture of very potent inflammatory chemicals from fat cells that play a significant role in the progression of heart disease, diabetes, and arthritis. The immune system is regulated by leptin and functions properly only when leptin levels in the body are maintained at healthy levels. Lastly, leptin affects the health of bones by regulating the amount of calcium they contain. High leptin levels inhibit the ability to grow new bone and can lead to osteoporosis.

Because leptin has such wide ranging effects on healthy weight management and metabolic wellness, there is increasing interest among medical professionals as well as consumers in finding ways to improve leptin function and reduce leptin resistance. These include nutritional solutions based on diets that specifically target leptin function, lifestyle changes that emphasize increased exercise and reduced sedentary behavior, as well as supplementation with dietary supplement ingredients that have been clinically tested to address leptin function.

* Dr. Abedon received his M.S. and PhD in plant genetics from the University of Wisconsin-Madison and a B.S. in Biochemistry from the University of Massachusetts-Amherst. Dr. Abedon may be contacted through Nutragenesis at 802-257-5345, or bruce@nutragenesis.com.