Relationship between Binge Eating and Stress

Relationship between Binge Eating and Stress Binge Eating and Stress: Is it Behavioral or Biological? ABSTRACT Stress is often inevitable in today’s fast paced world. People are struggling with positive coping mechanisms to deal with everyday life stressors. Binge eating (BE) can arise from maladaptive coping mechanisms that can be triggered from stress. Research has been limited in categorizing binge eating as either behavioral or biological due to BE being a recent disorder discovery and its overlap between neural and psychological dependence. This review aims to explain the differences between biological and psychological associations and the correlation stress has in both aspects of BE. Key Words: Binge Eating, Stress, Eating Disorder, Food Addiction, Psychological Dependence INTRODUCTION At some point in their lives, people have experienced some form of stress that lead them to turn to coping mechanisms to overcome the stressor(s). Work, college, family, and the pursuit of happiness can consume an individual to perform at optimum, sometimes unrealistic levels. In today’s world, college students and young professionals report the highest levels of stress compared to older generations. Thirty-nine percent of Millennials say their stress has increased in the last year, compared to 36 percent of Generation Xers, 33 percent of Baby Boomers and 29 percent of Matures (Stress by Genarations, 2012).   The form in which people deal with stress varies from individual but maladaptive forms of coping mechanisms such as Binge eating are becoming more popular among young individuals, particularly women (Fischer, 2017).   Binge Eating (BE) is consuming a very large amount of food within a short period of time with no sense of control over one’s eating, and no purgi ng afterwards (Parakeh).   People who have low self-esteem, anxiety, depression, body image issues, dieting obsessed, compulsive tendencies and academic perfection goals are more likely to develop an eating disorder such as BE (Cain, 2008).   BE so far has been classified as an eating disorder along with Anorexia Nervosa and Bulimia (Hardway, 2015), but there are more underlying symptoms that make it difficult to categorize under purely addictive psychological dependence or if it’s a neural response to stress. Psychological conditions such as depression, anxiety and low-self-esteem can manifest themselves when triggered by a situation or stressor that would make the individual turn to BE for relief or avoidance (Shelton, 2010). According to the Yale Food Addiction Scale (YFAS), which is a measure to identify individuals show signs related to substance dependence with the consumption of high fat/high sugar food such as food addiction (YFAS) individuals whose symptoms fit u nder YFAS have a strong correlation to food addiction. The YFAS proposes that the characteristics of binge eating goes hand in hand with what currently qualifies as substance dependence. Also, scores on the YFAS predicted binge eating behavior and emotional eating in a study of obese women who were dieting (Parylak, 2011). Alternatively, studies have been conducted that have found when stress levels are high, individuals are more likely to gravitate towards high-fat, high-sugar palatable foods in excess versus times of little to no stress. Neuronal activity monitored by a functional magnetic resonance imaging (fMRI) showed activation of various limbic system areas such as, the right amygdala (emotions, motivation), Cingulate cortex (emotion formation, memory), Hippocampus (regulates emotions), and Putamen (movement of limbs) (Figure 1, 2 and 3) (Born, 2010). Stress response initiates itself in the hypothalamus pituitary adrenal (HPA) axis and the sympathetic-adrenomedullary (SAM) sy stem (Adam, 2007). The overlapping and differential aspects of stress induced BE in the biological or psychological aspect have not yet been reviewed and the purpose of this review is to compare both sides, using research already done in both areas to determine how stress-induced BE should be categorized. Stress and Categories The Neuronal Approach Studies have been done to research the effects of stress on the brain mostly on animals like mice. The studies have revealed that in rats, stress can lead to choosing of lards and sugars over other foods (Adam, 2007). A study done relating animal and human literature took focus on the neuroendocrine mediators, insulin and cortisol and reviewed the neural circuitry of the reward system that is linked with food (Adam, 2007). Animal models resulted in glucocorticoids allowing for more pleasurable food intake and the consumption of drugs. A tail pinch in rats is considered a stressor and when the tail is pinched the rat would eat more caloric dense food. After a 24 hour rest period the rat would not eat to compensate for the calories taken in. However, if the tail pinching was consistent, the rat would eat more and still ate during the rest period. This can equate into human terms, as how constant severe stressors, for example college finals happening at the same time four research papers are due, and fast food available virtually everywhere can lead a very stressed person into a consumption frenzy of unlimited caloric dense food (Adam, 2007). The activation of the HPA axis as well as other transmitters accounts for the release of endogenous opioids which affect the body by trying to relax it when it’s in a heightened state. When the opioids are released (as response to a stressor) they contribute to the consumption of high-fat/high-sugar foods, and likewise these palatable foods sustain the release of the opioids. Therefore, if food is concluded to shut down stress pathways as before mentioned, (deactivating the HPA axis), so there’s not a continuous influx of stressful signal transduction (such as adrenaline release), and food is a coping mechanism of choice, then neurologically a stressed-out person is wired to seek out fatty foods to compensate for the amounts of stress triggering reactions in their body (Adam, 2007). In another research study, human subjects were tested under stressful and non-stressful conditions (a solvable math test and an unsolvable math test), given two fMRI’s and five blood tests. The test subjects were then asked to choose what kind of food appealed to them more after the test and a meal was also given before of their choosing. The results indicated that under stress food intake was larger than non-stressed. Subjects would have higher energy intake, protein intake and carbohydrate intake compared with the non-stressed subjects, as foods that were more palatable were chosen (higher in sugar, fat, salt, and more textured) (Born, 2010). These results correlate with other studies mentioned in this research, that also stated that stressed subjects have higher energy intakes therefore they tend to eat more nutrient dense foods compared to those who are not stressed. The areas of the brain that were stimulated were those that are linked to the reward system. The reward system is a dependence system is the brain that is activated by pleasurable foods, and drugs that leave the feeling of one wanting more. Constant stimulation of the reward system leads to desensitization which will increase the craving for palatable foods and have neurobiological adaptions to stimulate eating when not hungry. (Adam, 2007). The fMRI scans show regions of the limbic system that were activated when stressed given the choice to choose foods that were appealing (Figures 1,2 and 3) (Born, 2010). Brain reward in eating in the absence of hunger Figure 1. Sagittal (a), coronal (b) and transversal (c) sections, showing the GLM contrast of choosing something versus choosing nothing. Significant activation is visible in the left frontal cortex ( 21, 58, 13; Po0.05 FDR corrected). (Photo taken from Born, 2010). Figure 2. Two sagittal (a, b) sections at different planes and a transversal (c) section with the GLM contrast of choosing breakfast versus choosing a meal postprandially. There is a clear activation in the orbitofrontal cortex (3, 48, 1), frontal cortex (13, 61, 20 and 12, 63, 21) and putamen (18, 5, 5; Po0.05 FDR corrected). (Photo taken from Born 2010). Figure 3. Sagittal (a), coronal (b) and transversal (c) sections, showing the GLM contrast rest condition versus stress condition. Significant activation in present in the putamen (22, 4, 3 and 23, 11, 4) and the orbitofrontal cortex ( 8, 28, 6, Po0.05 FDR corrected). (Photo taken from Born, 2010). A sleep study was conducted identifying lack of sleep as a stressor. This is a common stressor of many college students for example that are loaded with excessive workloads, and young professionals who must meet the demands of their job fields. Subjects spent six days in bed for 9 hours or 4 hours and were submitted to MRI scanning on the sixth day and shown images of high and low calorie foods as well as nonfood items. The results showed overall neuronal activity was greater after restricted sleep than habitual sleep in response to food images. There was also more brain activity in areas of the brain associated with the reward pathways (Orbital frontal Cortex, insula, and regions of the basal ganglia). The brain regions in which activity was detected are related to motivation and desire so individuals who are not getting enough sleep are more prone to binge eating (St. Onge, 2012). Similarly, research has been conducted on nocturnal eating in response to stress and it was found that nocturnal eaters were more likely to binge eat than their counterparts. The stressors in this study were mostly psychological (self-esteem issues, body shaming, depression etc.) but as mentioned before if there is a lack of sleep it will trigger neuronal activity to seek out palatable food, and sometimes it is uncontrolled, leading to binge eating (Striegel-Moore, 2010).   Another study conducted previously tested subjects in a similar manner and found that those subjects with Night Eating Syndrome (NES) were also associated with binge eating (Colles, 2007). Obesity was concurrent with NES and most subjects that have NES were male according to Colles. The Psychological Approach Binge Eating is generally more closely associated with psychological factors such as depression, low self-esteem, poor body image perception, academic insufficiency, and weight-loss goals (Han, 2017). These factors are also closely associated to food addiction. Food addiction is defined just as substance addiction per the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) (Parakeh). The interlacing of terms between food addiction and binge eating has to do with the psychological factors both terms have in common. BE is characterized by behavioral and psychological symptoms such as the frequency of binge episodes, the amount of food consumed, and their occurrence in the absence of hunger. BE is also usually followed by guilt and feelings of disgust, shame, or depression, whereas FA is strictly more of a lack of self-control driven by an impulse for gratification or escape.   Both have a loss of control and impulsivity driving the conditions however, food addiction does not equate into binge eating (Davis, 2016). Research has been conducted to explore these psychological factors and a study was done comparing BE and FA statistically. The results indicated that subjects who fall under similar factors in both BE and FA are more likely to experience more frequent binge eating episodes, stronger cravings for food, and elevated levels of impulsivity and depressive symptoms than those with only BED (Burrows, 2017). Therefore, there is a difference between the two terms, however when used in combination, the effects on an individual can be more severe in contrast if they were suffering from just BE or FA alone. Stress can intensify the effects of BE and FA, as studies have shown the closer the behavior between FA and BE then the more likely there will be underlying implicated stress and anxious and depressive mood (Parylak, 2011). In a Chinese study the effects of stress and its causation to binge eating was studied in adolescent girls whose main stressor was academic perfection. Results showed that adolescents with greater life event stress, earlier maladaptive schemas and higher levels of impulsivity displayed more severe binge eating (Zhu, 2015). Therefore, adolescents who never learned positive coping mechanisms and were exposed to strong life stressors, were more likely to engage in binge eating. This is potentially dangerous among Millennial populations since it is possible they may have not learned positive coping mechanisms in adolescence and now many are in college where the pressure to excel academically is high. Healthy individuals who may not fit criteria for BE or FA can fall into either category depending on the level of stress associated in their lives, and how vulnerable they may be to psychological stressors (Hardaway, 2015). CONCLUSION Categorizing Binge Eating into either behavioral or biological categories is difficult because as research has shown components from both domains often interlace with one another. As discussed in this review many psychological stressors can give rise to neuronal activity that will biologically start a maladaptive cycle if the person is not equipped to handle the overwhelming stress. Unfortunately, diagnosis of BE is done incorrectly because patients are not always asked the appropriate questions regarding their eating habits. Diagnosis should take into consideration dopamine, opioid, acetylcholine, and serotonin neuro-circuitry that are associated within the brain reward regions, along with the psychological stressors (depression, self-esteem etc) that could be troubling the patient (Fornaro, 2016). Experimental drugs should as Lisdexamfetamine, have been tested among patients with mild BE and were found to reduce occurrence of BE episodes compared to the placebo. Future trials concerning safety and long term effects of the drug are needed to deem the drug fit for clinical treatment of BE (Fornaro, 2016). Currently self-help techniques including monitoring mood, stress, and eating behavior are preferred to the pharmaceutical approach, however self-help in patients with BE is not effective as compared to those without reported BE (Wolff, 2000).    Future work could incorporate neuropsychology as to understand the processes of signal transduction that can lead to behavioral problems. The infusion of psychology and biology is crucial in trying to understand and ultimately treat binge eating caused by stress. As of now such research and studies are scarce combining both components in association with BE. This review aimed to clarify the distinction between psychological and neuronal categorization of stress induced binge eating. As mentioned through this review, it is inaccurate to try and place BE into one category, as both categories are often present in individuals suffering from BE. The greater the awareness of this subject, the more equipped work places, colleges, and individuals can be to recognize potential stressors and the effects they have on those who are vulnerable to psychological conditions. Works Cited Adam, Tanja  C., and Elissa  S. Epel. Stress, eating and the reward system.  Physiology & Behavior, vol.  91, no.  4,  2007, pp.  449-458.   Born, J.  M., et al. 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