Obesity and Omega-3s Reduce Appetite
Appetite, by definition, is a term used to describe ones natural desire for food. It differs from hunger and satiety, and it is affected by a host of neural, hormonal and physical factors that may vary between individuals. This essay sets out to explain how these factors affect the appetite. In doing so the essay will explore the different regions of the brain (and the body) involved in its regulation and control, and the ways in which these areas may be pharmacologically and surgically manipulated to control the appetite itself.
Appetite can be described as ones instinctual desire for food. The smell and sight of food can trigger thoughts that lead to an increased flow of gastric juices in both the mouth and stomach. Sometimes however, the physical sensations aroused by appetite can be confused with feelings of hunger. Whereas hunger arises when the body requires and craves certain nutrients and calories, appetite arises only as a result of specific psychological triggers (such as memory and smell). Both appetite and hunger ensure the body is fed with food, leading to feeling of fullness and the desire to stop eating again. This full feeling and desire to discontinue eating is known as satiety.
Physiologically, appetite is controlled primarily by three parts of the brain. These include the orbitofrontal cortex of the limbic system, the arcuate nucleus within the appetite centre of the hypothalamus, and brainstem.
Neurons found in the orbitofrontal cortex of the brain’s limbic system are the first to be stimulated and respond to sensory signals that are generated in the presence of food[1]. It is here that the sensory inputs produced by food interact with hunger/satiety signals, allowing us to decipher how pleasant the food is and whether or not we have an appetite for it. It is proposed that hypothalamic neurons (that respond to hunger/satiety signals) send connections to the orbitofrontal cortex to inform it of these signals. It is also suggested that
Appetite can be described as ones instinctual desire for food. The smell and sight of food can trigger thoughts that lead to an increased flow of gastric juices in both the mouth and stomach. Sometimes however, the physical sensations aroused by appetite can be confused with feelings of hunger. Whereas hunger arises when the body requires and craves certain nutrients and calories, appetite arises only as a result of specific psychological triggers (such as memory and smell). Both appetite and hunger ensure the body is fed with food, leading to feeling of fullness and the desire to stop eating again. This full feeling and desire to discontinue eating is known as satiety.
Physiologically, appetite is controlled primarily by three parts of the brain. These include the orbitofrontal cortex of the limbic system, the arcuate nucleus within the appetite centre of the hypothalamus, and brainstem.
Neurons found in the orbitofrontal cortex of the brain’s limbic system are the first to be stimulated and respond to sensory signals that are generated in the presence of food[1]. It is here that the sensory inputs produced by food interact with hunger/satiety signals, allowing us to decipher how pleasant the food is and whether or not we have an appetite for it. It is proposed that hypothalamic neurons (that respond to hunger/satiety signals) send connections to the orbitofrontal cortex to inform it of these signals. It is also suggested that
Bibliography: Berthoud HR, Morrison C, 2008, ‘The Brain, appetite and obesity’, Pubmed, Neurobiology of Nutrition library Laboratory, pennington Biomedical Research Center, Louisiana Ststae University, USA, www.ncbi.nlm.gov/pubmed/18154499 E.T [10] Elaine Magee, MPH, RD , 2004, ‘Your “Hunger Hormones” ’, WebMD Weight Loss Clinic , MedicineNet.com ,USA, Viewed April 1, http://www.medicinenet.com/script/main/art.asp?articlekey=55992 [11] Tarek K [22] No author listed, 2008, ‘Genetics and Obesity’, Dietics Reference Guide, National Genetics Education and Development Centre, UK, viewed April 3, www.geneticseducation.nhs.uk [23] Please see footnote #3