Essay: Food intake and the reward system

Godthelp, H.F. (2014) Essay: Food intake and the reward system. Bachelor's Thesis, Biology.

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Abstract

Obesity is influenced by a complex interaction between genetic, environmental, behavioral and social factors and is a growing worldwide problem. Long and short-term signals contribute to the regulation of food intake, body weight and energy homeostasis, but all the complex regulation systems together do not prevent excessive energy intake. Food intake regulation could be overruled by psychology. In this review, we explore how the reward system interacts with the normal feedback mechanisms on food intake and focus on the role of melanin-concentrating hormone (MCH), leptin and ghrelin on reward. There is growing evidence for homeostatic energy balance regulators to be involved in the regulation of non-homeostatic behaviors and that they also modulate the rewarding nature of food. A deficit in the dopaminergic signalling pathway could provide a mechanism for food addiction and obesity, similar to the pathway of drug addiction. In obese individuals the dopamine receptor 2 expression in the dorsal striatum and VTA is reduced, which possibly increases food intake in order to compensate for the increased reward threshold. The hypothesis of food addiction is controversial. MCH is involved in regulating appetitive behavior and mediating rewarding aspects of food intake in the hypothalamic-limbic circuit. MCH increases dopamine levels and stimulates food intake. Leptin regulates motivational or hedonic elements of eating and interacts with hunger and satiety signals to induce satiety dependent suppression of liking and wanting of food. The leptin receptor (Lepr) in the ventral tegmental area (VTA) provides a direct function of a peripheral metabolic signal in the regulation of motivational or hedonic elements of eating. Ghrelin plays a role in hedonic and incentive responses to food-related cues. In the VTA, ghrelin stimulates food intake and reward-based feeding behavior via its receptor, which could contribute to development of obesity. Taken together, evidence is found that psychology, via the mesolimbic pathways, plays a major role in homeostatic food intake and adipose store regulation and seems to be able to overrule the physiological mechanisms of feeding behavior and could lead to obesity. Metabolic signals may favor food consumption by enhancing the hedonic and incentive responses to food-related cues and contribute thus to development of obesity.

Item Type:	Thesis (Bachelor's Thesis)
Degree programme:	Biology
Thesis type:	Bachelor's Thesis
Language:	English
Date Deposited:	15 Feb 2018 07:57
Last Modified:	15 Feb 2018 07:57
URI:	https://fse.studenttheses.ub.rug.nl/id/eprint/11870

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