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Leptin & Cortisol in Eating Disorders (aka My Research Paper)

Health, NutritionHaley Hansen2 Comments

Eating disorders can leave harmful effects on survivors, prior to the destruction that takes place while the disorder is in full effect. In the midst of an eating disorder, one can suffer from digestive issues, fatigue, and dry skin, among other symptoms (“Anorexia nervosa – medical complications”, 2015). An in-depth look at the most common eating disorder - anorexia nervosa - reveals a physiological effect beyond a thin stature and restricted food intake: potentially serious hormonal imbalances in levels of leptin and cortisol.

Anorexia Nervosa Explained

The most prevalent of all eating disorders, anorexia nervosa is one characterized by weight loss or inadequate weight gain, difficulty maintaining a proper weight, body image distortion, and sometimes exercise addiction (“Anorexia: Overview and Statistics”). A collection of studies in the International Journal of Eating Disorders found a prevalence rate of up to about 1% among young females for strictly defined anorexia nervosa (Wijbrand, 2003, p. 385). The vast majority of these studies found significantly higher prevalence rates for partial syndromes of anorexia, meaning that the full set of diagnostic criteria for AN was not met, but rather a smaller handful of signs of the disorder. While a mere 1% of the world’s population can seem a small number, and while most medical professionals do classify anorexia nervosa as a rare mental illness when compared with others, the incidence rates are rising rapidly in the 15-19 year-old female age group (Smink, 2012, p. 408).

Survivors of anorexia nervosa can likely vividly remember the signs and symptoms associated, though during the disorder, one probably would have denied anything unusual at all. What typically begins with an innocent decrease in calories/overall food intake in pursuit of weight loss often progresses into a restriction or elimination of at least one entire food group (i.e. carbohydrates or fats). From there, specific food rituals, like excessive chewing and/or organization of foods and eating patterns develop. Concerns about eating in public and/or social gatherings promote withdrawal and isolation. Other mechanisms of avoiding meals include random excuses to exclude oneself and denial of hunger, as well as consistent over-exercising (“Warning Signs and Symptoms”).

Psychologically, a preoccupation with food often clouds one’s mind with thoughts of how to consume the least amount possible, how to “burn off” calories consumed, fear of eating or gaining fat, etc. Additionally, denial of one’s low body weight, extreme influence of one’s weight or physical shape on emotional and mental state, and body dysmorphia – fixation on a perceived flaw or imperfection in one’s physical appearance, body shape, or specific feature – become mentally and socially consuming (Phillips). Flexibility with daily life occurrences like eating and making social plans diminishes as one seeks control and relies on specific, strict dietary patterns, and isolation and withdrawal often result (“Warning Signs and Symptoms”).

DSM-5 diagnostic criteria include restriction of energy intake to amounts far lower than recommended, intense fear of weight gain despite one’s current weight, and a disturbance in one’s own perception of body shape and consequent extreme self-evaluation and denial of the disorder (“Anorexia: Overview and Statistics”). Atypical anorexia occurs when one shows some or all symptoms of AN but is not underweight, despite weight loss.

A main consequence of prolonged AN is a disruption of the body’s ability to regulate hormones. Two hormones most significantly affected include leptin and cortisol, which involve maintenance of appetite and satiation and management of stress levels, respectively. At first, this disruption might not manifest itself obviously, but if not treated, can over time lead to inability to regain a healthy amount of weight and/or damage and even loss of cognition.

Leptin

Leptin is a hormone directly tied to and secreted by body fat. Sometimes called the “satiety hormone”, leptin’s main function is signaling to the brain that energy is present in the body, so appetite can decrease (What Is Leptin?). Specifically, leptin “travels from fat to the bloodstream and binds with the hypothalamus region of the brain, which is involved in regulating appetite” (Tara, 2016, p. 42). Therefore, a higher level of circulating leptin in the blood typically equals a lower appetite (assuming no metabolic issues like obesity or diabetes are present) (Margetic, 2002, p. 1409-1410).

A study published in the International Journal of Eating Disorders compared the plasma leptin levels of patients with anorexia nervosa to that of normal control women without the disorder. Each individual’s level of various hormones including leptin was measured, as well as menstrual score, percent body fat, and eating behavior score. Researchers found a significant relationship between leptin levels and body fat mass, eating behavior score, and menstrual status. Eating behavior score was defined on a scale of one to five based on the patient’s 48-hour diet history prior to blood testing – a lower score was given to patients with lower calorie intake and a higher score to those with extreme caloric intake. Menstrual score on a scale of one to three was based on regularity of the menstrual cycle for the three months prior to blood testing – amenorrhea for at least three months was given a score of one while a regular cycle was given a score of three. Overall, lower leptin levels (observed mostly in the patients with AN) were seen paired with lower body fat mass, eating behavior score, and menstrual score. This signified that symptoms of AN, mainly decreased caloric intake and excessive exercise leading to extreme weight loss, lower the body’s leptin levels, and consequently, menstrual regulation (Nakai, 1999, p. 32).

The same study also pointed out that leptin has been linked to reproductive function. Though it does not play a direct role in the initiation of puberty and the reproductive cycle, leptin does act in a permissive fashion, as “a metabolic gate to allow pubertal maturation to proceed” (Nakai, 1999, p. 34). In another study, both male and female mice with mutations resulting in leptin deficiency were observed to be infertile, and only achieved proper sexual development when provided with leptin. Mice with low leptin levels displayed “morphological and biochemical abnormalities”, like low sperm counts and underweight, underdeveloped reproductive organs (Elias, 2012, p. 842). Similarly, the pituitary contents of luteinizing hormone and follicular stimulating hormone, two main hormones that regulate ovulation, were low in leptin-deficient mice (Elias, 2012, p. 843) (Martin, 2013).

Researchers for the Journal of Clinical Endocrinology and Metabolism found that during the weight restoration phase of AN treatment, leptin levels reached what was considered “normal” (that of healthy individuals without AN), but patients were still significantly underweight. This helps explain why some suffering from AN struggle in gaining weight even after recovering from the disorder – leptin levels have increased, so appetite has decreased. Leptin levels likely increase at a faster rate than weight gain does, which represents potential difficulty some might face in the treatment and full weight-restoration process (Mantzoros, 1997, p. 1850).

A study published in the research journal PLOS ONE found results that agreed with that of the previous study. These researchers found that in previously high-severity AN patients, now weight-restored patients, an increase in leptin levels was correlated with an increased incidence of psychological disturbances like depression, anxiety, and stress. Researchers are unsure of the causes and mechanisms behind this occurrence, but it is possible that the reality of weight gain could have shocked and upset patients who weren’t mentally recovered and prepared for the changes in physical appearance that weight gain brings (Stroe-Kunold, 2016, p. 10).

Current research surrounding hormone restoration, especially that for leptin levels, rests on the side of the more overweight and obese who likely suffer from leptin resistance, rather than deficiency – explaining how to regulate leptin in speeding up metabolism and increasing the body’s rate of burning fat as a source of energy and decreasing appetite. This is not the desired mechanism in restoring hormone levels for those with AN, as a fat-burning metabolism and decreased appetite will likely worsen the existing weight issue.

It is clear that leptin levels are low in those with anorexia nervosa. Low leptin levels should display an increased appetite and amount of food consumed, but the opposite is seen in those with AN, probably due to a preoccupation with the nutrition facts of foods, body weight and appearance, and overall fear and anxiety surrounding food (“Warning Signs and Symptoms”). During the weight restoration and treatment phase, leptin levels have been seen to increase in patients with AN in a linear fashion with weight and BMI – a good sign. However, to maintain this weight, reshaping the mindset of one with AN is just as important, if not more so. Without a positive relationship with food and an understanding of its essential role in everyday life, a patient with AN who gains weight and restores leptin could lose the weight after a period of time due to leptin’s function in decreasing appetite. 

Cortisol

A steroid hormone that helps regulate metabolism, prevent inflammation, enhance memory, and control electrolyte balance and blood pressure, cortisol is the body’s main hormone when it comes to handling to stress. When the body experiences stressful situations, cortisol secretion increases to respond to the stress-inducing situation (Cortisol, 2017). Stress arises not only when the body is under harmful physical attack, but also when it is unable to mentally and/or emotionally cope with certain situations, and this is usually when disorders like depression and anxiety develop.

AN induces stress on the body not only by forcing the individual into a nutrient-deficit, but also by altering the neurological systems within the brain, specifically those that regulate enjoyment of food and emotional sensitivity. Psychologically, the brains of patients with AN show enhanced feelings of pleasure and reward when starvation is chosen over eating, which helps explain the difficulty these patients find in gaining weight. “Disturbed interoceptive awareness of satiety and hunger” play a significant role in preventing patients with AN from recognizing bodily cues to eat. Additionally, these patients tend to feel high levels of anxiety in situations involving food, and therefore turn to starvation as a coping mechanism to decrease the anxiety (Kaye, 2014, p. 1-2).

Patients with AN show abnormalities in CT scans similar to patients with Cushing’s syndrome – ventricular enlargement in the brain and cerebral atrophy (Kellner, 1983, p. 191). This particular study found that the degree of cortisol secretion and ventricular size shared a strong linear relationship. A significant increase in cortisol can increase brain ventricular size, eventually leading to a condition called “normal pressure hydrocephalus”, in which the cerebrospinal fluid does not drain, but rather builds up and causes further expansion of the ventricles. The resulting pressure on the brain from the ventricles typically results in symptoms like compromised memory and cognition, also known as dementia (Lava, 2016). Methods to prevent NPH, specifically that caused by AN, includes reaching and maintaining a healthy weight and exercise routine (Lava, 2016).

Of the several harmful consequences an eating disorder can cause, the hormonal disruptions – specifically leptin and cortisol – can be the most physically detrimental. In the recovery phase, survivors can find the weight-gain process challenging because leptin levels tend to increase at a faster rate than actual weight gain. Increasing cortisol levels during AN, if not treated in time, can cause brain alterations similar to that which occurs during Cushing’s syndrome. Though these changes are often difficult to deal with, they can be prevented and treated by increasing awareness of the damaging effects of AN, and decreasing negative stigmas surrounding AN. As society becomes more aware of eating disorders and proper prevention and treatment methods, these hormonal disturbances can become less and less prevalent.

Bibliography

"Anorexia nervosa - medical complications." Journal of Eating Disorders 3.11 (2015): 1-8. PubMed. Web. 7 May 2017.

"Anorexia: Overview and Statistics." NEDA. National Eating Disorders Association, n.d. Web. 3 May 2017.

Elias, C. F., & Purohit, D. (2012). Leptin signaling and circuits in puberty and fertility. Cellular and Molecular Life Sciences,70(5), 841-862. doi:10.1007/s00018-012-1095-1

Phillips, Katharine, MD. "About BDD." International OCD Foundation. International OCD Foundation (IOCDF), n.d. Web. 7 May 2017.

Smink, Frederique R. E., Daphne Van Hoeken, and Hans W. Hoek. "Epidemiology of   Eating Disorders: Incidence, Prevalence, and Mortality Rates." Current Psychiatry Reports 14.4 (2012): 406-14. Springer Link. Web. 7 May 2017.

Wijbrand Hoek, Hans, and Daphne Van Hoeken. "Review of the Prevalence and Incidence of Eating Disorders." International Journal of Eating Disorders 34.3 (2003): 383-94. Wiley Online Library. Web. 3 May 2017.

"Warning Signs and Symptoms." NEDA. National Eating Disorders Association, n.d. Web. 7 May 2017.

Phillips, Katharine, MD. "About BDD." International OCD Foundation. International OCD Foundation (IOCDF), n.d. Web. 7 May 2017.

Tara, Sylvia, PhD. The Secret Life of Fat. N.p.: W. W. Norton & Co., n.d. Print.

Margetic, S., C. Gazzola, GG. Pegg, and RA Hill. "Leptin: A review of its peripheral actions and interactions." International Journal of Obesity 26 (2002): 1407-433. Nature. Nature Publishing Group, 2002. Web. 7 May 2017.

Martin, K., MD, & Pinkerton, J., MD. (2013, May). Women's Reproductive Health Information. Retrieved May 22, 2017, from http://www.hormone.org/diseases-and-conditions/womens-health/womens-reproductive-health

Mantzoros, C. (1997). Cerebrospinal Fluid Leptin in Anorexia Nervosa: Correlation with Nutritional Status and Potential Role in Resistance to Weight Gain. Journal of Clinical Endocrinology & Metabolism,82(6), 1845-1851. doi:10.1210/jc.82.6.1845

Nakai, Y., Hamagaki, S., Kato, S., Seino, Y., Takagi, R., & Kurimoto, F. (1999). Role of leptin in women with eating disorders. International Journal of Eating Disorders,26(1), 29-35. doi:10.1002/(sici)1098-108x(199907)26:1<29::aid-eat4>3.0.co;2-h

What is Leptin? (n.d.). Retrieved May 24, 2017, from http://www.hormone.org/hormones-and-health/what-do-hormones-do/cortisol/leptin

Stroe-Kunold, E., Buckert, M., Friederich, H., Wesche, D., Kopf, S., Herzog, W., & Wild, B. (2016). Time Course of Leptin in Patients with Anorexia Nervosa during Inpatient Treatment: Longitudinal Relationships to BMI and Psychological Factors. Plos One,11(12), 1-14. doi:10.1371/journal.pone.0166843

Cortisol. (2017, January). Retrieved May 25, 2017, from http://www.yourhormones.info/Hormones/Cortisol.aspx

Eating Disorders. (n.d.). Retrieved May 25, 2017, from https://www.adaa.org/understanding-anxiety/related-illnesses/eating-disorders

Kellner, C. H., Rubinow, D. R., Gold, P. W., & Post, R. M. (1983). Relationship of Cortisol Hypersecretion to Brain CT Alterations in Depressed Patients. Psychiatry Research,8(3), 191-197. doi:https://doi.org/10.1016/0165-1781(83)90062-8

Kaye, W. H., & Weltzin, T. E. (1997). Relationship of depression, anxiety, and obsessionality to state of illness in anorexia nervosa. International Journal of Eating Disorders,21(4), 367-376. Retrieved May 25, 2017, from http://eds.a.ebscohost.com/ehost/pdfviewer/pdfviewer?sid=c7d63f5b-ddd5-4df4-aecf-01592439a021%40sessionmgr4007&vid=2&hid=4105

Lava, N., MD (Ed.). (2016, September 11). What is Normal Pressure Hydrocephalus? Retrieved May 27, 2017, from http://www.webmd.com/brain/normal-pressure-hydrocephalus#1

Kaye, W. H., MD. (2014, May 6). Eating Disorders: Understanding Anorexia Nervosa. Retrieved May 27, 2017, from file:///Users/haleyhansen/Downloads/Psychiatric_Times_-_Eating_Disorders_Understanding_Anorexia_Nervosa_-_2014-05-28.pdf

When Food is More Than Fuel

Food, Nutrition, HealthHaley Hansen11 Comments

"Food is fuel." You've heard that saying, right? Are you tired of it like I am? 

I'm a human. But I'm more than just a human. I'm also a student, in some situations. I'm also a blogger and a Jesus-lover and a plant-based-diet enthusiast and a 20-something girl who is still figuring life out (baby steps, ya' know?). My point is that I'm more than a pair of legs and arms attached to this chunk of torso. 

In the same way, food is more than fuel. 

True Food Kitchen - seasonal salad + some kind of pizza. Both duh-licious.&nbsp;

True Food Kitchen - seasonal salad + some kind of pizza. Both duh-licious. 

Think back to that one professor in college who captivated your attention in every lecture. For me, it's Dr. Nicholson (where're my Mustang Nutrition Majors at?!). She's my professor for Cal Poly's Contemporary Issues in Foodservice lecture, and she's one of the - if not THE - very best professors from whom I've ever learned. The class isn't really anything challenging or bursting with new information, but that's just it. There's something simple yet intriguing about digging into the various reasons we, as a culture and as individuals, eat. 

Last week, in class, she shared with us a story of when she was a working RD volunteering at an ethnic food festival. Several visitors approached her questioning how they can make one of their culture's staple dishes - latkes - lower in oil or oil-free, without stripping it of its classic flavor. She paused to think, as did I in that moment. Well, you can bake them in the oven or possibly "fry" them in vegetable stock... but...

Bliss Cafe - eggplant parmesan + protein buddha bowl + turmeric jasmine rice.

Bliss Cafe - eggplant parmesan + protein buddha bowl + turmeric jasmine rice.

But the oil serves a deeper purpose than an ingredient to crisp up the potato latkes - it represents the presence of God's Spirit. By frying the latkes in what an RD might see as a swimming pool of oil, the Jews who celebrate this holiday see it as recognition and honoring of their God. 

The oil is more than the crisp-factor. The oil is more than fat. The latkes are more than shredded potatoes. The latkes are more than carbs. 

Clearly, my professor's story triggered the turning of some wheels in my brain. I let those wheels turn as they led my thoughts into how I view food in different situations, which I realized I want to change. 

Whole Foods - two messes of a salad.&nbsp;

Whole Foods - two messes of a salad. 

When food IS mostly fuel...

There's no denying that one of food's main purposes is to provide energy for the human body. The brain needs carbohydrates for cognition and the limbs need them for movement. The muscles need protein for structure and function. The bones need vitamins and minerals for stability, and fats to absorb those nutrients. 

Viewing food from the "food is fuel" perspective can be beneficial if weight loss is the goal. For an overweight individual or for one who doesn't have a grasp on proper nutrition, developing the understanding that food provides nutrients and energy the body needs in order to function optimally (or minimally, at the very least), can be a key in attaining/maintaining health.

GT's kombucha - my favorite non-water beverage, besides coffee.

GT's kombucha - my favorite non-water beverage, besides coffee.

  • After a workout, the body usually needs proteins and carbohydrates most of all. Why? To rebuild the muscles that broke down and refuel the glycogen stores that provided the energy. 
  • Before an exam (for all my fellow students), the brain can best remember important material when it feeds on berries, walnuts, and leafy green vegetables. Oh, and don't forget the carbohydrates.
  • While recovering from emotional eating, I viewed food as just macro- and micro-nutrients - protein, carbs, and fat, and vitamins and minerals. I didn't allow myself to see it as anything that could lift my mood because doing so would encourage me to continue eating and continue eating and continue eating until I felt better (after which I only felt worse). 

When food is MORE THAN just fuel...

A virgin margarita from some restaurant in Claremont, CA.

A virgin margarita from some restaurant in Claremont, CA.

Now, whaddya' say we have some FUN?! Food is fun! Food is a vehicle for creativity and self-expression. Food encourages exploration of various cultures, values, tastes, and cravings. 

And most of all, food provides the ropes for and ties the knots within in a community or group of people. Take Food52 for an example. This was one of the first food-blogging communities I discovered way back when I first began, and I fell in love immediately. At the time, most of my mind revolved around food's nutrition label, but a small part spoke up and craved the culinary experience that Food52 highlights behind each recipe. 

Donut Friend - apple fritter + donut holes w/ chocolate drizzle &amp; caramel sauce + blueberry classic donut.

Donut Friend - apple fritter + donut holes w/ chocolate drizzle & caramel sauce + blueberry classic donut.

  • When a group of close family and/or friends are gathered around a table, whether in the comfort of a home or the excitement of a restaurant, food is about sharing and tasting, and the food is only a small part of the get-together. 
  • Even though one meal may have been big (possibly too big) and filling beyond comfort, sometimes there's just magically room for a vegan apple fritter. And some of that room might be influenced by friends who crave said vegan donuts, but hey, that's okay, too. Either way, there's still room. 
  • Backyard barbecues in the summer, movie nights with friends, and late-night cravings for donuts (can you tell I like donuts?) just scream "I'M MORE THAN FOOD". Don't they?

I'm not saying that food is never fuel or that it is only fuel. Isn't that part of what makes food to indescribably worth it, though? It is all of the above. 

Oh, hey look. More Donut Friend. And more friends! (@beazysbites, @constancelyeating, @emilieeats)

Oh, hey look. More Donut Friend. And more friends! (@beazysbites, @constancelyeating, @emilieeats)

Want to read more about why food isn't just fuel? Check out this article from the founder of Precision Nutrition. I love his perspective, his scientific evidence, and of course, his support of food as a cultural celebration. 

Me in my element - aka a kitchen, cooking vegan food, eating Minimalist Baker's vegan lentil sloppy joe's. Happy. Hungry.&nbsp;

Me in my element - aka a kitchen, cooking vegan food, eating Minimalist Baker's vegan lentil sloppy joe's. Happy. Hungry. 

Food is sometimes pre- or post-workout fuel. In that moment, its usually a banana and peanut butter or a protein smoothie for me. But, other times it may be a communal celebration with my roomies at the end of a rough week, in which its a ginormous pizza topped - no, piled - with veggies and vegan cheese. 

Just like you are not a static being with just legs and arms and a body, food is not just protein and carbs and fat. Just like you wouldn't want to be narrowed into in any one category (i.e. student, athlete, girl/boy, etc.), don't try to squeeze all foods into "good"/"healthy" or "bad"/"unhealthy". 

I'm no dietitian, though I am studying to become one, so please don't think of me as your one-stop-shop for all things nutrition- and ED-recovery related. If you'd like, I can point you towards some of the RD's who have helped me immensely in my journey, and I can share my story with you. 

I hope you've found this helpful! Leave a comment below and tell me your favorite foods - when is food fuel for YOU? When is it a form of community and celebration? 

Bliss Cafe (again) - cacao walnut brownie cookie. The chocolate chip to cookie ratio is what keeps me coming back. On. Point.&nbsp;

Bliss Cafe (again) - cacao walnut brownie cookie. The chocolate chip to cookie ratio is what keeps me coming back. On. Point. 

Thanks for reading!