Cortisol is a steroid "stress" hormone produced from cholesterol in the two adrenal glands located on top of each kidney. It is released in response to events like waking in the morning, exercising and acute stress. Cortisol helps to maintain blood pressure, and provides energy by stimulating fat and carbohydrate metabolism. When permanently elevated, as it can be in people who are under chronic stress, cortisol can have detrimental effects on weight, immune function and chronic disease risk. Cushing's syndrome is a well-known constellation of signs and symptoms produced by an excessive level of cortisol.
Blood Sugar Imbalance
Cortisol helps to regulate blood sugar levels by regulating insulin release and producing glucose in the liver. When cortisol levels are chronically elevated, insulin production is suppressed and blood sugar levels is consistently elevated. Theoretically, this can increase the risk for type 2 diabetes. A study outlined in the December 2002 issue of the "Journal of Clinical Endocrinology & Metabolism" demonstrated that patients with type 2 diabetes or glucose intolerance exhibit abnormalities in cortisol action.
Obesity
Cortisol mobilizes carbohydrates and fat for quick energy when we are under stress--the "fight or flight" response. This causes an increase in appetite to replace the carbohydrates and fat. A study published in the January 2001 issue of "Psychoneuroendocrinolgy" showed that people with elevated cortisol levels are associated with increased appetite, cravings for sugar and weight gain. However, elevated cortisol due to temporary stress will not likely cause weight gain.
Gastrointestinal Effects
Elevated cortisol suppresses the parasympathetic nervous system which is responsible for activities like digestion and absorption. As a result, digestion and absorption are compromised--indigestion develops and the mucosal lining becomes inflamed. Unfortunately, this inflammation leads to increased production of cortisol, and the cycle continues.
Immune System
Cortisol functions to reduce inflammation in the body. But if cortisol levels are chronically elevated, it will suppress the immune system. According to Dr. Weinstein in his book "The Stress Effect," this can lead to a number of problems related to suppressed immune system: an increased susceptibility to colds and illnesses, increased risk of cancer and increased tendency to develop food allergies.
Fertility Problems
Elevated cortisol can lead to disruption of normal ovulation and menstrual cycles or erectile dysfunction. Cortisol is produced in the same glands as sex hormones, therefore excess cortisol production may decrease production of sex hormones.
Cardiovascular Disease
In the April 5, 2005, isssue of the "Quarterly Journal of Medicine," Dr. Sher states that elevated cortisol has many effects that promote heart disease. One effect of high cortisol levels is that it directs fat to the visceral regions by activating lipoprotein lipase and inhibiting lipid mobilization, increasing the risk for cardiovascular disease. Cortisol also constricts blood vessels and increases blood pressure, as in the fight-or-flight situation. Over time, this can lead to vessel damage and plaque buildup.
References
- "Journal of Clinical Endocrinology & Metabolism"; Abnormal cortisol metabolism and tissue sensitivity to cortisol in patients with glucose intolerance; R.C. Andrews, O. Herlihy et al.; 2002
- "Psychoneuroendocrinology"; Stress may add bite to appetite in women: a laboratory study of stress-induced cortisol and eating behavior; Epel E, Lapidus, B et al; 2001
- "The Stress Effect"; Dr. R. Weinstein; 2004.
- "Quarterly Journal of Medicine"; Type D personality: The heart, stress, and cortisol; Sher ;. 2005
- "Textbook of Functional Medicine". Jones DS, Quinn S.; 2006
