Neuropeptide Y (NPY) is an amino acid that acts as a neurotransmitter in the brain and in the autonomic nervous system of humans. In the brain it is produced in the hypothalamus and is thought to cause increase of food
Neuropeptide Y (NPY) is an amino acid that acts as a neurotransmitter in the brain and in the autonomic nervous system of humans. In the brain it is produced in the hypothalamus and is thought to cause increase of food intake and storage of energy as fat, reducing anxiety and stress, reducing the perception of pain and lowering blood pressure.
Since the 1970s, researchers have been linking NPY to stress and to eating disorders such as obesity. Across the board, scientists have noted that increasing levels of NPY increases food intake, just as decrease of NPY decreases food intake.
So how does this happen?
Four factors that interrelate lead to obesity. They are: An increase in glucocorticosteroid concentrations in plasma; insensitivity or resistance to insulin; mutation of leptin receptor and an increase in NPY release.
Sustained high levels of glucocorticosteroids stimulate an increase in blood sugar that activates the release of insulin to try to regulate blood sugar. In obese people, insulin resistance is frequently present and causes extremely high levels of blood sugar leading to diabetes. High levels of glucocorticosteroids also cause an increase in NPY.
Glucocorticosteroids (the stress hormones) also cause a rise in blood sugar by facilitating the breakdown of protein and fat and stored glycogen to sugar in times of stress (the flight or fight reaction). Simultaneously, obesity related diabetes and the mutation of the leptin receptor results in inhibition of food intake. The discovery of leptin has led to the theory that it maintains fat stores at a relatively constant level.
Leptin is a peptide hormone synthesized and secreted by adipose tissue in proportion to its mass. This hormone circulates in blood and acts on the hypothalamus to regulate food intake and energy expenditure.
When fat mass falls, plasma leptin levels fall, stimulating appetite and suppressing energy expenditure until fat mass is restored. When fat mass increases, leptin levels increase, suppressing appetite until weight is lost. This physiological system ensures that total energy stores are maintained within a relatively narrow range.
So here’s a kicker for you — animal studies have shown that repeated or chronic stress and a high-fat, high-sugar diet stimulate the release of NPY, causing white fat to build up in the abdomen. This, of course, leads to metabolic syndrome with the usual accompanying diagnosis of diabetes.
Researchers believe that they can possibly eliminate fat from undesirable areas of the body and re-distribute it to other areas where it may be more desirable by manipulating the levels of NPY in the fat of human bodies. How’s that for fooling with the system? On a therapeutic side, pharmacological manipulation of NPY can lead to reduced abdominal obesity and metabolic abnormalities.
Also on the good side, high levels of NPY can allow people to have higher resistance to post traumatic stress disorder and help them perform better under stress.
So, if thin is in, and fat is where it’s at, the best thing to do is exercise to relieve stress and watch the fatty and sugary food intake because the chemistry is against you. Exercise helps regulate your hormones and reduces stress, as well as burns calories. Your body will love you for it!
• Jane Riley, M.S., B.A., C.P.T., Certified Nutritional Adviser, can be reached at janerileyfitness@gmail.com, 212-1451 or www.janerileyfitness.com.
