Are you overweight? One way you can determine whether you need to lose weight is by identifying your leptin levels. Leptin is a hormone secreted by the body’s fat cells. Its receptor is found in the hypothalamus, the part of the brain that controls your hunger and body weight. The discovery of this hormone has led to a greater understanding of how fat cells are formed and how we respond to hunger. These fat cells are no longer viewed as a part of tissue that merely stores excess calories. Instead, we now know that they are dynamic cells that work with the endocrine system to produce hormones that regulate appetite and metabolism.
Each fat cell has an internal sensor that demands food. As more fat enters the fat cell, that cell secretes leptin in response. The secretion of the leptin hormone signals your brain, “telling” you that you’ve achieved satiety: the feeling you get when you’ve eaten enough. The more leptin that’s present, the stronger the signal to your brain, and the less hungry you feel. However, if there is leptin overload, which often occurs when you are overweight, or if the signal doesn’t get received, your brain won’t transmit the message to stop eating. Unfortunately, the consequence is that you will continue to eat past the point of satiety, which leads to the accumulation of body fat. It becomes a vicious cycle then as, subsequently, more fat cells also accumulate and their food requirements need to be met.
As we age, our bodies can become resistant to the leptin message. This happens because the heavier you get, the more resistant you become to the leptin you produce, resulting in a weaker signal to your brain. A low leptin signal then sets off a cascade of brain chemical reactions, particularly in relation to metabolism. For example, when leptin is released, dopamine (a main brain chemical) production also increases, that enables you to be able to burn off the foods you eat instead of storing them as fat cells. However, without the leptin message, metabolism falls as well.
High leptin levels are correlated with obesity, while moderate to low leptin levels are associated with better fitness. However, extremely low leptin levels may be associated with other hormonal loss. For example, increased levels of the hormone cortisol also lead to increased leptin resistance, which contributes to even more weight gain. Also, low leptin levels lead to lower levels of estrogen and progesterone for women, which signal menopause; and for men, testosterone, which signal male menopause.
Your leptin level can be determined by a simple blood test. Call to make an appointment today to have a full body check-up and to learn more about nutrients and diet that positively affect leptin and other hormonal imbalances. You’re Only as Young as Your Oldest Part.
Eric R. Braverman, M.D.
Dr. Braverman is a Summa Cum Laude and Phi Beta Kappa graduate of Brandeis University and NYU Medical School, did brain research at Harvard Medical School, and trained at an affiliate of Yale Medical School. He is acknowledged worldwide as an expert in brain-based diagnosis and treatment, and he lectures to and trains doctors in anti-aging medicine.