Cortisol — Its Role in Stress, Inflammation, and Indications for Diet Therapy
Cortisol — Its Role  in Stress, Inflammation, and Indications for Diet Therapy
By Dina Aronson, MS,  RD
Today’s Dietitian
Vol.  11 No. 11 P. 38
Cortisol, a glucocorticoid (steroid hormone), is produced  from cholesterol in the two adrenal glands located on top of each kidney. It is  normally released in response to events and circumstances such as waking up in  the morning, exercising, and acute stress. Cortisol’s far-reaching, systemic  effects play many roles in the body’s effort to carry out its processes and  maintain homeostasis.
Of interest to the dietetics community, cortisol also plays  an important role in human nutrition. It regulates energy by selecting the  right type and amount of substrate (carbohydrate, fat, or protein) the body  needs to meet the physiological demands placed on it. When chronically  elevated, cortisol can have deleterious effects on weight, immune function, and  chronic disease risk.
Cortisol (along with its partner epinephrine) is best known  for its involvement in the “fight-or-flight” response and temporary increase in  energy production, at the expense of processes that are not required for  immediate survival. The resulting biochemical and hormonal imbalances (ideally)  resolve due to a hormonally driven negative feedback loop. The following is a  typical example of how the stress response operates as its intended survival  mechanism:
1. An individual  is faced with a stressor.
2. A complex  hormonal cascade ensues, and the adrenals secrete cortisol.
3. Cortisol  prepares the body for a fight-or-flight response by flooding it with glucose,  supplying an immediate energy source to large muscles.
4. Cortisol  inhibits insulin production in an attempt to prevent glucose from being stored,  favoring its immediate use.
5. Cortisol  narrows the arteries while the epinephrine increases heart rate, both of which  force blood to pump harder and faster.
6. The individual  addresses and resolves the situation.
7. Hormone levels  return to normal.
So what’s the problem? In short, the theory is that with our  ever-stressed, fast-paced lifestyle, our bodies are pumping out cortisol almost  constantly, which can wreak havoc on our health. This whole-body process,  mediated by hormones and the immune system, identifies cortisol as one of the many  players. But isolating its role helps put into context the many complex  mechanisms that lead to specific physiological damage.
Whole-Body Effects of  Elevated Cortisol
Blood Sugar Imbalance and Diabetes
Under stressful conditions, cortisol provides the body with  glucose by tapping into protein stores via gluconeogenesis in the liver. This  energy can help an individual fight or flee a stressor. However, elevated  cortisol over the long term consistently produces glucose, leading to increased  blood sugar levels.
Theoretically, this mechanism can increase the risk for type  2 diabetes, although a causative factor is unknown.1 Since a principal function  of cortisol is to thwart the effect of insulin—essentially rendering the cells  insulin resistant—the body remains in a general insulin-resistant state when  cortisol levels are chronically elevated. Over time, the pancreas struggles to  keep up with the high demand for insulin, glucose levels in the blood remain  high, the cells cannot get the sugar they need, and the cycle continues.
Weight Gain and Obesity
Repeated elevation of cortisol can lead to weight gain.2 One  way is via visceral fat storage. Cortisol can mobilize triglycerides from  storage and relocate them to visceral fat cells (those under the muscle, deep  in the abdomen). Cortisol also aids adipocytes’ development into mature fat  cells. The biochemical process at the cellular level has to do with enzyme  control (11-hydroxysteroid dehydrogenase), which converts cortisone to cortisol  in adipose tissue. More of these enzymes in the visceral fat cells may mean  greater amounts of cortisol produced at the tissue level, adding insult to  injury (since the adrenals are already pumping out cortisol). Also, visceral  fat cells have more cortisol receptors than subcutaneous fat.
A second way in which cortisol may be involved in weight  gain goes back to the blood sugar-insulin problem. Consistently high blood  glucose levels along with insulin suppression lead to cells that are starved of  glucose. But those cells are crying out for energy, and one way to regulate is  to send hunger signals to the brain. This can lead to overeating. And, of  course, unused glucose is eventually stored as body fat.
Another connection is cortisol’s effect on appetite and  cravings for high-calorie foods. Studies have demonstrated a direct association  between cortisol levels and calorie intake in populations of women.3 Cortisol  may directly influence appetite and cravings by binding to hypothalamus  receptors in the brain. Cortisol also indirectly influences appetite by  modulating other hormones and stress responsive factors known to stimulate  appetite.
Immune System Suppression
Cortisol functions to reduce inflammation in the body, which  is good, but over time, these efforts to reduce inflammation also suppress the  immune system. Chronic inflammation, caused by lifestyle factors such as poor  diet and stress, helps to keep cortisol levels soaring, wreaking havoc on the  immune system. An unchecked immune system responding to unabated inflammation  can lead to myriad problems: an increased susceptibility to colds and other  illnesses, an increased risk of cancer, the tendency to develop food allergies,  an increased risk of an assortment of gastrointestinal issues (because a  healthy intestine is dependent on a healthy immune system), and possibly an  increased risk of autoimmune disease.4,5
Gastrointestinal Problems
Cortisol activates the sympathetic nervous system, causing  all of the physiologic responses previously described. As a rule, the parasympathetic  nervous system must then be suppressed, since the two systems cannot operate  simultaneously. The parasympathetic nervous system is stimulated during quiet  activities such as eating, which is important because for the body to best use  food energy, enzymes and hormones controlling digestion and absorption must be  working at their peak performance.
Imagine what goes on in a cortisol-flooded, stressed-out  body when food is consumed: Digestion and absorption are compromised,  indigestion develops, and the mucosal lining becomes irritated and inflamed.  This may sound familiar. Ulcers are more common during stressful times, and  many people with irritable bowel syndrome and colitis report improvement in  their symptoms when they master stress management.5 And, of course, the  resulting mucosal inflammation leads to the increased production of cortisol,  and the cycle continues as the body becomes increasingly taxed.4
Cardiovascular Disease
As we’ve seen, cortisol constricts blood vessels and  increases blood pressure to enhance the delivery of oxygenated blood. This is  advantageous for fight-or-flight situations but not perpetually. Over time,  such arterial constriction and high blood pressure can lead to vessel damage  and plaque buildup—the perfect scenario for a heart attack. This may explain  why stressed-out type A (and the newly recognized type D) personalities are at  significantly greater risk for heart disease than the more relaxed type B  personalities.6
Fertility Problems
Elevated cortisol relating to prolonged stress can lend  itself to erectile dysfunction or the disruption of normal ovulation and  menstrual cycles. Furthermore, the androgenic sex hormones are produced in the  same glands as cortisol and epinephrine, so excess cortisol production may hamper  optimal production of these sex hormones.5
Other Issues
Long-term stress and elevated cortisol may also be linked to  insomnia, chronic fatigue syndrome, thyroid disorders, dementia, depression,  and other conditions.4,5
Assessing Cortisol  Levels
The adrenal stress index (ASI), a salivary test, is the  preferred test for adrenal function and a well-accepted, noninvasive, reliable  indication of cortisol levels.7-10 However, a trained professional should  interpret the results because factors such as age, gender, timing with the  menstrual cycle, pregnancy, lactation, smoking, medications, medical  conditions, caffeine and alcohol consumption, caloric intake, and other test  results (particularly related hormone tests such as sex hormone levels) will  contextualize the significance and meaning of the measurement.9,10
The ASI is available as a home kit. Four saliva samples are  taken at specific times and then shipped to a laboratory for analysis.  Conveniently, in addition to measuring the adrenal hormones cortisol and  dehydroepiandrosterone, the same test also measures antibodies to gliadin,  often used as a marker for intestinal inflammation, Candida infections, and  sensitivity to gluten-containing grains. (Note that this test cannot diagnose  gluten sensitivity definitively.)7
A blood cortisol test is available, but it is considered  inferior to the salivary test for three reasons: It tests cortisol levels only  at one given point in time, which provides less information than levels at four  times (which reveals important imbalances); the blood test itself (or simply  going to the doctor) can stress a person enough to cause a cortisol surge; and  it is considered less sensitive because it measures the total hormone level as  opposed to specific components.5
The Good News
So far, it may seem as though stressed-out folks are  destined for failed health despite their best intentions. Fortunately, there is  much we can do for our clients (and ourselves) to reverse the path of  destruction. The best approach to keeping cortisol levels at bay is mastering  stress management and optimizing diet.
Stress Management
First, regardless of our scope of practice, we can always  recommend strategies for effective stress management. Books such as Woodson  Merrell’s The Source have some powerful yet commonsense, evidence-based  advice for de-stressing and regaining optimal health. Some strategies include  getting more and better quality sleep, breath work, acupuncture,  cardio/resistance/relaxation exercises, and addressing psychological/emotional  issues. Minimizing stress may require a team approach; we can acknowledge its  importance and leave the details to the experts.
The Anti-Inflammatory Diet
Systemic inflammation, as noted previously, causes elevated  cortisol levels. If we can naturally decrease inflammation in the body and  minimize stress, decreased cortisol levels should follow, resulting in  decreased chronic disease risk and improved wellness. The biochemical processes  leading to and abating inflammation are complex and multi-faceted, but as  experts in diet and lifestyle, we can make a significant difference.
Like any diet designed to manage a condition, there is no  one perfect anti-inflammatory diet. However, based on known properties of foods  and clinical research, we can devise a generally low-inflammatory diet and  tweak it over time. Obviously, maximizing the anti-inflammatory foods and  minimizing the proinflammatory ones is a big step toward controlling  inflammation. Incidentally, dietary strategies for controlling inflammation may  also help with adrenal support in general, since diet can directly affect  adrenal burden (eg, cortisol is released in response to metabolic demands).
Since lifestyle factors are generally the most significant  modulators of inflammation, nutrition professionals can make a huge difference  in our clients’ and patients’ overall health.4 The following is a general list  of diet and lifestyle factors believed to be the most significant contributors  to inflammation:
• high glycemic load;
• saturated and trans fatty acids;
• caffeine;
• insufficient intake of micronutrients and antioxidants;
• a low-fiber diet;