Role of Glucose in Mood Disorders, Term Paper Example

Abstract

Research has suggested that there is role between the amount of glucose intake and mood disorders. Studies investigation the role of glucose and Glyoxalase₁ (GLO₁) and have shown that glucose levels in diabetes patients are linked to depression. In addition, Glyoxalase₁ (GLO₁) levels in mice were linked to behavioral disorders, such as anxiety and depression. Furthermore, studies have found that women who chose a more healthy diet were less likely to be depressed and men who ate healthier were less anxious. The link between behavior and glucose levels needs further investigation at both the molecular and behavior level in humans.

Research suggests that behavior in food selection occurs though the visual system in humans. The sight of food in regard to behavior has been found to result in a variation of emotional, physical and cognitive responses. For instance, a physical response to visual cues includes the preparation of the body for the intake of food, along with the anticipation of a physiological response, such as a change in heart rate. In addition, emotional responses are also observed and suggested to have evolved as a mechanism to increase survival through the urge to eat. Furthermore, cognitive responses have been found to result from the sight of food, such as memory from the last encounter or specific food experience. Recent research has investigated how brain mechanisms are involved in responding to visual food cues, as an insight to eating behavior. It has been found that different brain sections are activated or triggered in response to visual cues resulting in behavior changes, such as self-regulation. (Van der Laana et al., 2011) Other studies have investigated factors that maintain the brain’s response to visual cues, such as energy content in food and hunger status of an individual. The studies have illustrated that these factors influence the types of food that people choose, such as higher energy content food eaten when individuals are hungry. Although these studies have yielded correlations with behavior and food selection, the results of these studies were not consistent. (Fuhrer et al., 2008) Therefore, other studies have further investigated the role of additional factors, such as mood and gender, to food behavioral studies. In particular, these studies have focused on the effects of specific foods, such as sugar, on mood disorders. The current paper therefore, investigates the role of sugar, in the form of glucose, and its effects on mood disorders.

Glucose is the basic form of carbohydrates, as well as the main fuel for brain activity. With that, glucose is essential for cognitive development and maintenance. In addition, previous literature has found a correlation with brain activity and glucose use. (Markus, 2007) Glycation is a process that occurs when a sugar molecule, such as glucose or fructose covalently bond to a protein or lipid molecule. These covalently bonded compounds are absorbed into the body during digestion at approximately 30%. Glyoxalase₁ (GLO₁) is an enzyme that is used in a metabolic pathway and detoxifies compounds such as methylgloxal (MG). MG levels increase with higher glucose cellular conditions, as seen in diabetes. In order to prevent MG and its cytotoxic effects, (GLO₁) converts MG to less cytotoxic substance known as d-lactate. Studies have recently correlated GLO₁and behavior. For instance, in a research study using mice, results suggested that (GLO₁) was associated with anxiety like behavior, depression and neuropathic pain. (Distler and Palmer, 2012)Studies have also suggested the mechanism underlying the behavior of GLO₁. A literature review conducted by Distler and Palmer (2012) investigated the correlation between GLO₁ and behavior. Researchers found that mice that were injected with MG over a six day period, exhibited a less anxious behavior compared to the GLO1 treated mice. In addition, chronic injection of MG showed anti-depressant behavior in the mice. (Distler and Palmer, 2012)

At the molecular level, the link between glucose and behavior disorders have been investigated in mice and rats; however, human studies have also been conducted using qualitative measures, such as phenotypic evidence and questionaries’ regarding daily diets in both adults and adolescents, in order to correlate a link between high glucose and mood disorders. One study conducted by Davison and Kaplan (2012) investigated the food intake and blood cholesterol levels in adults with mood disorders. The purpose of this study was to support previous literature indicating a link of nutrition to mood and little quantitative research has been conducted in this area. The study methods included obtaining three day food logs from 97 adults diagnosed with mood disorders. The quality of the food and types of food were evaluated per Canada’s Food Guide and North American dietary guidelines. The results of the study indicated that a larger percentage of the sample size consumer less than the recommended number of servings of grains, vegetables and fruits. In addition, the results indicated that a larger percentage of the sample size consumer more high-fat products, processed meats, salty food, and sugar food. The researcher’s discussion suggests that nutrition is in fact possibly related to mood disorders and therefore, patients with diagnosed mood disorders could benefit from a dietary intervention.

Other recent research has suggested the role of diet and its association with mental disorders such as depression and anxiety. In a study conduct by Jacka et al. (2011), the association between the quality of food intake, dietary patterns and mental disorders were observed. The study used 5731 men and women ages 46-49 and 70-74 years of age. The diets were assessed using a questionnaire and the mental health status was assessed using a Hospital and Anxiety Depression Scale. A healthy diet was considered healthy if the food groups contained fruit, vegetables, low-fat dairy, fish, whole grains and non-processed red meat. The results of the study indicated that healthy diets were inversely related to depression in women and anxiety in men. For instance, it was found that women who scored higher in regard to a healthy diet were less likely to be depressed and men who ate health had a reduction in anxiety. In addition, participants who indicated that they used a traditional Norwegian diet were also associated with a decreased depression. Overall, the study showed that a better, healthier diet was associated with a reduction in depression and anxiety in women and men, respectively.

In another study conducted by Jacka et al. (2010), the role of diet in depression was investigated in relation to adequate nutrition and brain development in adolescence. Previous research has shown the role of nutrition in adult depression, therefore, the purpose was to investigate the relation in adolescence. The researchers conducted the study using 7114 adolescents between ages 10-14 years through the Australian Health Neighborhoods Study. The study used a questionnaire to determine the quality of the diet in regard to health or unhealthy. In addition, another questionnaire was used in order to determine whether or not the adolescents were depressed. Factors such as gender, age, education, parental status, social status, and economic status, family issues, dieting issues, physical fitness and smoking were considered and adjusted. The results of the study found that there was a correlation between diet and adolescent depression. In addition, the study found that the association did not relate to other factors, such as family issues or socioeconomic statuses.

Since research has suggested that mood disorders are associated with nutrition intake, other research has investigated factors such as obesity in individuals with mood disorders from adolescent ages. In a study conducted by Goodman and Whitake (2002), depression was compared to the development of obesity in adolescents. The purpose was to correlate depressed mood as a predictive factor to obesity. The study used 9374 adolescents in grade seven through 12 using in-home interviews approved for the National Longitudinal Study of Adolescent Health. The interviews occurred two times, one year apart. In addition, depression was analyzed using the Center for Epidemiologic Studies of Depression Scale. The Basal Metabolic Rate (BMI) was also measured and computed. Adolescents scored at a 95^th were considered obese. This study also took into consideration family and economic status, education and parental obesity.The results of this study found that depression did increase the risk for the development of obesity in adolescence. The study found that depressed moods at the baseline study independently predicted obesity when other factors were controlled for, such as age, gender, socioeconomic status, etc.

Other studies have shown that depression and diabetes type 2 are related. For instance, in a study conducted by Mwamburi et al., (2011), elderly individuals that were experiencing higher levels of depression had a higher insulin level compared to elderly who were not experiencing depression. In addition, not all individuals with mood disorders are obese or overweight; therefore, researchers are suggesting that there is a link between higher carbohydrate and sugar intake and individuals with mood disorders since not all individuals are overweight with mood disorders but evidence has suggested a higher carbohydrate/sugar intake in the majority of individuals with mood disorders. Additional research has supported this theory suggesting that the glycemic index (GI) and glycemic load (GL) by showing that diets high in dairy and fruit but low in potatoes and cereals had better insulin sensitivity. (Du et al., 2008)

As mentioned previously, other research has begun to focus on areas in the brain that are linked to food stimuli. For instance, research has been conducted to show activity within the visual cortex of the brain. In order to test the hypothesis that activity in the visual cortex is influenced by emotional stimuli, functional magnetic resonance imaging (fMRI) was used to investigate a correlation between Positive and Negative Affects and activity win the occipital cortex. Thirteen women, of normal weight, were examining after consuming high calorie and lower calorie types of food. Statistical analyses from the results showed that the women who participate in the study eating higher calorie foods were significantly correlated with activity in the visual cortex. The results suggest that sensory processing is influenced by perceptual experience of a particular stimulus. (Killgore and Yurgelun-Todd, 2007)

Conclusion

Overall, there is evidence supporting the idea that nutrition is linked to mood disorders. In studying perception of the brain starting from a food stimuli to the actual physical and physiological attributes, researcher are able to suggest that higher glucose levels are correlated with mood disorders. Recent studies have shown there is an associate of GLO1 with behavior in mice and rats; however, much research is needed in order to obtain more information to the extent at which GLO1 regulates physiological functions and human behavior. It is known that MG can help reduce the cytotoxic effects of GLO1; therefore, it can be suggested that an increase in GLO1 would results in an inhibitory effect. In addition, human studies regarding glucose levels and mood disorders, suggest a link between a non-quality type of diet, such as high fat and high sugar and mood disorders, such as depression. This research has shown correlations in both adults and adolescents and type 2 diabetes. More research should be conducted specifying the amount of sugar intake in depressed individuals in order to correlate sugar and mood disorders.

References

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Jacka FN, Kremer, PJ, Leslie, ER, Berk M, Patton GC, Toumbourou, JW, Williams JW. (2010). Associations between diet quality and depressed mood in adolescents: results from the Australian Healthy Neighbourhoods Study. Aust N Z J Psychiatry. 44(5):435-42.

Jacka, FN, Myketun, A, Berk, M, Bjelland, I, Tell, GS. (2011). The association between habitual diet quality and the common mental disorders in community-dwelling adults: the Hordaland Health study. Psychosom Med. 2011 Jul-Aug;73(6):483-90.

Killgore WD and Yurgelun-Todd DA. (2007).Positive affect modulates activity in the visual cortex to images of high calorie foods. Int J Neurosci. 117(5):643-53.

Markus, C.R. (2007). Effects of carbohydrates on brain tryptophan availabilityand stress performance. Biological Psychology. 76:83–90.

Mwamburi, DM, Liebson, E., Folstein, M. Bungay, K, Tucker, KL., Qui, WQ. (2011). Depression and glycemic intake in the homebound elderly. J Affect Disord. 132(1-2):94-98.

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