Appetite Control 1
Ghrelin and Leptin: A Closer Look Into Appetite Regulation
Katie P. Haarala
Dr. Betty Larson
FND 426 Community Nutrition
January 20, 2009
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Ghrelin and Leptin: A Closer Look Into Appetite Regulation
The regulation of the human appetite reaches much farther than the stomach; the
hormonal phenomenon behind why we eat, when we eat, and what we eat is currently a
research topic that is growing in popularity. Recent studies discuss the hormones
ghrelin and leptin as an encourager and inhibitor of appetite stimulation. Research
produced in The Journal of Nutrition discussed the current views on the supposed
actions of ghrelin. “The current view holds that gastric ghrelin crosses the blood brain
barrier and, in concert with ghrelin produced locally in the hypothalamus, engages the
networks of neuropeptide Y..” (Kalra et.al, 2005). This process will lead to an increased
appetite drive. The hormone leptin has an opposing relationship with ghrelin; it has
been shown to decrease the appetite. The same study found that hyperleptinemia “may
suppress ghrelin secretion and this may account for the reported suppressed ghrelin
secretion in obese patients and rats.” (Kalra, 2005) An understanding that these
hormones may be playing a vital role in appetite generates the need to continue
research on these chemical processes. It is imperative to also discuss what behaviors
may impact the levels of ghrelin and leptin produced in the body.
Adequate Sleep and the Affect on Ghrelin and Leptin Levels
Sleep is not only important to rejuvenate the body after a long day, but to
maintain normal levels of ghrelin and leptin. A study published in the Public Library of
Science Journal studied correlation between hours of sleep individuals got in a night
and how it affected their ghrelin and leptin levels. It was concluded that those
participants that received 5 hours of sleep versus the recommended 8 had higher
ghrelin levels and reduced leptin levels. It is believed that these fluctuations increase
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the appetite, possibly explaining why individuals who usually do not receive enough
sleep tend to have higher BMI’s. The study concluded “In Western societies, where
chronic sleep restriction is common and food is widely available, changes in appetite
regulatory hormones with sleep curtailment may contribute to obesity” (Taheri et al.,
2005).
Dietary Intake and the Affect on Ghrelin and Leptin Levels
Sleeping patterns are not the only behavior that have an impact on an individuals
ghrelin and leptin levels; an individuals macronutrient intake has also been shown to
affect ghrelin and leptin secretion. In the journal of Biochemical and Biophysical
Research Communications, an experiment performed on Long-Evans rats found that
ghrelin secretion was sensitive to diet composition. Rats that were on a high fat diet for
14 weeks were associated with lower ghrelin levels; however, as the carbohydrate
intake increased in the diet, so did ghrelin levels along with blood glucose and body
weight (Beck et al., 2002). It is believed that same results in humans; those with higher
carbohydrate, particularly in the form of fructose, reduce their circulating leptin. A study
published in The Journal of Clinical Endocrinology and Metabolism noted that women
with higher fructose containing meals versus high glucose containing meals saw a
reduction in circulating leptin and insulin along with increased ghrelin concentrations. It
was stated that “decreases of circulating insulin and leptin and increased ghrelin
concentrations, as demonstrated in this study, could lead to increased caloric intake and
ultimately contribute to weight gain and obesity during chronic consumption of diets high
in fructose” (Teff, K. et al., 2004).
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Conclusion
Appetite regulation continues to be a current research topic with many further
areas to study. It is important to realize the hormones ghrelin and leptin play a vital role
in controlling the appetite signals. These hormones have been shown to be affected by
behavioral patterns such as sleep and whether or not the individuals diet has high levels
of carbohydrate, particularly pertaining to fructose. Healthy behavioral patterns, studies
suggest, will lead to overall regulated levels of ghrelin and leptin produced in the body.
Both are necessary hormones involved in controlling the appetite; however, it is
imperative that both ghrelin and leptin remain in levels that will not induce possible
weight gain.
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References
Beck, B., Musse, N., & Stricker-Krongrad, A. (2002). Ghrelin, Macronutrient
Intake and Dietary Preferences in Long–Evans Rats. Biochemical and Biophysical
Research Communications, 292(4), 1031-1035. Retrieved January 19, 2009, from
http://www.sciencedirect.comscience_ob=ArticleURL&_udi=B6WBK-45K18D11C&_user=10&_rdoc=1&_fmt=&
Kalra, S., Ueno, N., & Kalra, P. (2005). Stimulation of Appetite by Ghrelin Is
Regulated by Leptin Restraint. The Journal of Nutrition, 135(5), 1331-1335. Retrieved
January 9, 2019, from http://jn.nutrition.org/cgi/reprint/
Taheri S, Lin L, Austin D, Young T, Mignot E (2004) Short Sleep Duration Is
Associated with Reduced Leptin, Elevated Ghrelin, and Increased Body Mass Index.
PLoS Med 1(3): e62 doi:10.1371/journal.pmed.0010062
Teff, K., Elliot, S., Tschop, M., Kieffer, T., Rader, D., Heiman, M., Townsend, R.,
Keim, N., Aleisso, D., & Havel, P. (2004). Dietary Fructose Reduces Circulating Insulin
and Leptin, Attenuates Postprandial Suppression of Ghrelin, and Increases
Triglycerides in Women. The Journal of Clinical Endocrinology and Metabolism, 89(6),
2963-2972. Retrieved January 19, 2009, from http://jcem.endojournals.org/cgi/