The Physiological Mechanisms of Food Intake and Its Regulation Report

This report delves into the intricate mechanisms governing food intake and its regulation within the human body. It emphasizes the crucial role of hormones like leptin and ghrelin, as well as pancreatic hormones such as insulin, amylin, and glucagon, in controlling appetite and energy storage. The report explores the neuronal signaling processes involving peptides from the gut, adipose tissue, and brain, highlighting the hypothalamus's function as a central integration point. The discussion covers the influence of various factors on hunger and satiety, offering insights into the physiological underpinnings of food consumption and its metabolic implications. The study's importance lies in its potential to inform dietary interventions and treatments for related disorders, particularly those involving hormonal imbalances and neuronal pathway dysfunctions.

Running head: FOOD INTAKE AND ITS REGULATION
Food intake and its regulation
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1FOOD INTAKE AND ITS REGULATION
Introduction:
Food intake and its regulation is an important aspect of the human body as it
is a deciding factor of how well our body works and metabolizes. The study is crucial
to develop dietary charts and treatments for the disorders involving these pathways.
The mechanism also involves the interaction between the brain, gut and the adipose
tissues. The influence of various physiological mechanisms during the food intake
process gives an insight of the way the food that humans consume gets processed
and digested. The study is important because it helps in researches involved in
manipulative studies of the hormones and other factors associated with it. The
discussion in the report deals with the different hormones and the neurological
signaling processes that are involved in the procedure. The different factors that are
involved in controlling hunger for long or short duration will also be given emphasis in
the following paragraphs.
Discussion:
Influence of the leptin and ghrelin hormones in the food consumption process:
The levels of the hormone ghrelin and leptin are crucial factors in the process
of food intake. They have a long term effect in the regulation of consumed food. The
fluctuations in these hormone levels, act as a determinant for the motivation or
demotivation of humans to consume food. During ingestion of food, the adipocytes
release the hormone leptin in the body. While consumption, the levels of leptin
increases which reduces a person’s eagerness to ingest (Rezai-Zadeh et al., 2014).
On the other hand, when the levels of ghrelin hormone increases, the appetite of a
person increases. It is the only orexigenic molecule known to be present in the
human body. During the state of satiety, the levels of leptin increases and that of
ghrelin decreases.
Necessity of signaling by pancreatic hormones during ingestion (insulin,
amylin and glucagon):
The hormones insulin and amylin are secreted in the pancreas by the beta
cells, both the hormones provide signals that help in storage of energy as visceral
adipose tissues. Insulin directly acts to suppress the production and secretion of

2FOOD INTAKE AND ITS REGULATION
glucose. It also gets transported in the mediobasal part of hypothalamus in the brain,
to elicit a catabolic response, this response reduces excessive intake of food which
helps in maintenance of body weight (Varela & Horvath, 2012). Amylin works
similarly by stimulating the neurons present in the hindbrain to reduce food
consumption. The hormone glucagon is secreted by the alpha cells, it increases the
secretion of glucose in the liver, it also reduces the meal size, although the signaling
process is different from that of insulin and amylin. It sends signals to the brain in
which the vagus nerves act as mediators.
Mechanisms of other hormone peptides involved in neuronal signal for
regulation of food intake:
The neuronal circuits of the adipose tissue, gut and brain have several types
of peptides that are known to inhibit the urge of appetite in the human body (Hussain
& Bloom, 2013). The peptides of the gut such as peptide tyrosine tyrosine (PYY) and
cholecustokinin are some of the examples. Several circulating hormones from the
gut, influence the working of the specific neurons present in hypothalamus called the
arcuate nucleus (ARC) and tractus solitaries (NTS) through circumventricular organ
(Fromentin et al., 2012). The gastrointestinal vagal afferents on the other hand,
converge in the brainstem’s NTS, this projection carries signal to the brain’s
hypothalamus which reduces the hunger. ARC works as a center of integration
which in association with two subpopulation of neurons enhances and influences
appetite. One of the subpopulations expresses agouti related protein (AgRP) and
neuropeptide Y (NPY); these increase the appetite, whereas, the other population
expresses cocaine and pro-opiomelanocortin (POMC); these reduce or inhibit food
intake (Florant & Healy, 2012). The axons of the neurons present in the
paraventricular nucleus (PVN) influence the secretion of anorexigenic peptides like
thyrotropin releasing hormone (TRH), oxytocin and corticotropin-releasing hormone
(CRH) (Duca & Covasa, 2012).

3FOOD INTAKE AND ITS REGULATION
Role of hypothalamus in regulation of consumed food:
The food intake regulation is a mechanism that involves humoral signals and
varied neuronal pathways that lead to the hypothalamus. The processing of the
neuronal circuits in the hypothalamus happens first and then descends commands
via the spinal neurons and vagal to the body (Morton et al., 2014). The
hypothalamus is found to have receptors that are sensitive to metabolism of glucose,
stomach distension, body fat reserve, cannabinoid receptors and neuropeptides. The
mentioned receptors along with the neurons present in the different groups of cells
present in hypothalamus, stimulate intake of food (Begg & Woods, 2013). As
mentioned in the above paragraphs, the hypothalamus is also involved in the
processing of insulin which is also involved in the procession of food intake.
Conclusion:
From the above discussion, it can be concluded that, understanding the
mechanism by which the process of food consumption happens is of major
importance as it decides the rate of metabolism in human body. The intricate study
of the hormone signaling involving several neurons and their receptors, help in
constructing treatment and dietary charts for the physiological disorders related to
the pathways involved in the process. The knowledge of the orexigenic and the
anorexigenic peptides involved in the process, helps in manipulative studies of the
pathways which is necessary for development of therapy involving them.

4FOOD INTAKE AND ITS REGULATION
References:
Begg, D. P., & Woods, S. C. (2013). The endocrinology of food intake. Nature
Reviews Endocrinology, 9(10), 584-597.
Duca, F. A., & Covasa, M. (2012). Current and emerging concepts on the role of
peripheral signals in the control of food intake and development of
obesity. British Journal of Nutrition, 108(5), 778-793.
Florant, G. L., & Healy, J. E. (2012). The regulation of food intake in mammalian
hibernators: a review. Journal of Comparative Physiology B, 182(4), 451-467.
Fromentin, G., Darcel, N., Chaumontet, C., Marsset-Baglieri, A., Nadkarni, N., &
Tomé, D. (2012). Peripheral and central mechanisms involved in the control of
food intake by dietary amino acids and proteins. Nutrition research
reviews, 25(1), 29-39.
Hussain, S. S., & Bloom, S. R. (2013). The regulation of food intake by the gut-brain
axis: implications for obesity. International Journal of Obesity, 37(5), 625.
Morton, G. J., Meek, T. H., & Schwartz, M. W. (2014). Neurobiology of food intake in
health and disease. Nature Reviews Neuroscience, 15(6), 367-378.
Rezai-Zadeh, K., Yu, S., Jiang, Y., Laque, A., Schwartzenburg, C., Morrison, C.
D., ... & Münzberg, H. (2014). Leptin receptor neurons in the dorsomedial
hypothalamus are key regulators of energy expenditure and body weight, but
not food intake. Molecular metabolism, 3(7), 681-693.
Varela, L., & Horvath, T. L. (2012). Leptin and insulin pathways in POMC and AgRP
neurons that modulate energy balance and glucose homeostasis. EMBO
reports, 13(12), 1079-1086.