subject: Your Hypothalamus Overeating and Obesity [print this page] Your Hypothalamus Overeating and Obesity Your Hypothalamus Overeating and Obesity
Your hypothalamus is responsible for a number of very important functions in your body. It helps regulate, among other things, blood pressure, heart rate, body temperature, sexual desire, hunger and thirst. You've probably already heard that your hypothalamus is an important regulator of hunger in your body. When you feel hungry, it's your hypothalamus signaling hunger. When you feel full, it's your hypothalamus signaling satiety.
But, it's a bit more complex. Hunger has both physical and psychological aspects. When you encounter the fragrant aroma of good food cooking in the oven you're going to start thinking about food and your desire for food will increase. You may not physically be hungry, but your mind says it's about time to eat.
The hypothalamus is the main regulator of physical hunger. The lateral hypothalamus is associated with hunger and the ventromedial hypothalamus is associated with feelings of satiety or fullness. In addition, the paraventricular hypothalamus is associated with the regulation of hunger.
Your body is in a constant state of tension trying to maintain a balance between hunger and satiety. Two important hormonal messengers that signal the hypothalamus are ghrelin and leptin.
Ghrelin is produced by an empty stomach and the pancreas. The concentration of ghrelin increases before meals and decreases after eating. Ghrelin activates neurons that make neuropeptite Y (NPY). The NPY is causes animals to eat voraciously. NPY gives you strong urges to eat.
Leptin is a hormone secreted from fat cells that circulate in the blood. More leptin is secreted when energy levels are high. Leptin inhibits the NPY cells and reduces the desire to eat. Leptin bonds to certain receptors in the hypothalamus to signal satiety. In a very small number of people, a genetic mutation causes a deficiency of leptin which results in obesity. The vast majority of obese people, however, do not have this genetic defect.
Another possible cause of the obesity epidemic was recently discovered. A study on mice indicates that fructose inhibited the actions of leptin and caused the rats to eat more than necessary, making them obese. While further studies are needed, including human studies, it would be wise to reduce your consumption of fructose. You'll find fructose in many packaged or manufactured foods in various forms include high fructose core syrup, honey, and molasses.
Another important component of hunger is the blood concentration of glucose. Cells in the ventromedial nucleus and the lateral hypothalamus are directly affected by glucose. When glucose levels are low the lateral hypothalamus signals hunger and your desire for food increases. Higher glucose levels help prevent hunger signals.
As you can tell, feelings of hunger and satiety are complex and no one solution will result in a complete cure for overeating. A lot remains up to the individual to manage proper eating and a healthy amount of exercise. An overall healthy lifestyle is still the best method of maintaining a healthy weight.
