EFFECT OF REGULAR GARLIC INGESTION ON BODY WEIGHT AND BLOOD GLUCOSE: A CASE STUDY IN MICE

Abstract

Garlic a perennial erect plant is known to have sulphur-containing compounds that act on the hypothalamus increasing the sensitivity of the hypothalamus to leptin which alters the set point at which satiety is reached causing an organism to eat less. Nine mice (six of which were obese) were used in this study and grouped into three. Groups A and B were made of 3 obese mice each whereas group C consisted of 3 non-obese mice. For group A and group C mice, 20 ml aqueous garlic extract was added to their feed daily whereas no garlic was added to the feed of group B mice. The study was carried out over a period of 44 days. The weight and blood glucose was measured weekly and the average for each group was computed. Results indicated that Group A mice recorded a reduction in mean body weight by 46.5% (p<0.05). Group B mice had significant increase in mean body weight by 46.2% (p<0.05). The blood glucose level dropped significantly by 18.5% (p<0.05) in group A mice. Garlic had weight loss and hypoglycemic effect in obese mice. These effects were absent in non-obese mice.

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Djankpa et al., IJPSR, 2012; Vol. 3(5): 1364-1366 ISSN: 0975-8232
Available online on www.ijpsr.com 1364
IJPSR (2012), Vol. 3, Issue 05 (Research Article)
Received on 08 January, 2012; received in revised form 02 March, 2012; accepted 19 April, 2012
EFFECT OF REGULAR GARLIC INGESTION ON BODY WEIGHT AND BLOOD GLUCOSE: A CASE STUDY IN MICE
F.T. Djankpa, A. Osonuga*, J. Ekpale, C.E. Quaye, P. Otoo, O.A. Osonuga and S.K. Amoah
School of Medical Sciences, University of Cape Coast, Cape Coast, Ghana
ABSTRACT
Garlic a perennial erect plant is known to have sulphur-containing
compounds that act on the hypothalamus increasing the sensitivity of the
hypothalamus to leptin which alters the set point at which satiety is reached
causing an organism to eat less. Nine mice (six of which were obese) were
used in this study and grouped into three. Groups A and B were made of 3
obese mice each whereas group C consisted of 3 non-obese mice. For group
A and group C mice, 20 ml aqueous garlic extract was added to their feed
daily whereas no garlic was added to the feed of group B mice. The study was
carried out over a period of 44 days. The weight and blood glucose was
measured weekly and the average for each group was computed. Results
indicated that Group A mice recorded a reduction in mean body weight by
46.5% (p<0.05). Group B mice had significant increase in mean body weight
by 46.2% (p<0.05). The blood glucose level dropped significantly by 18.5%
(p<0.05) in group A mice. Garlic had weight loss and hypoglycemic effect in
obese mice. These effects were absent in non-obese mice.
INTRODUCTION: Garlic (Allium sativum Lin.) contains a
variety of active compounds such as selenium and
germanium that exhibit sulphur antioxidant property,
as well as vitamin A, C and E which help scavenge
harmful free radicals and also eliminate low density
lipoprotein from blood thereby increasing high density
lipoprotein in the blood 1. Obesity is a condition in
which there is excessive triglyceride storage in the
body and long-term regulation of body weight is
largely influenced by the degree of obesity 2. There are
serious health implications associated with obesity
such as cardiovascular disease (mainly hypertension,
heart disease and stroke), type 2 diabetes,
musculoskeletal disorders like osteoarthritis, and some
cancers such as endometrial, breast and colon 3. Fat
cells secrete a protein hormone called leptin in
proportion to the amount of triglyceride they have
stored 4. Thus, in a long term, excess ingestion of
calories resulting in increased fat deposition triggers an
increase in leptin secretion.
Leptin impinges on its receptors in the hypothalamus
to alter the set point at which satiety is reached, so
that the individual eats less due to loss of appetite and,
hence, assimilates fewer calories 4, 5. Although leptin is
a circulating signal that reduces appetite, obese people
generally have an unusually high circulating
concentration of leptin. Obese individuals are
therefore resistant to the effect of leptin due to low
sensitivity of the hypothalamus to leptin 6.
According to Sukander et al., garlic has been proposed
to have direct anti-atherogenic (preventive) and anti-
atherosclerotic (causing regression) effects at the
artery wall. The possible mechanisms of garlic as lipid
lowering agent are its inhibitory effect on hepatic
activities of lipogenic and cholesterogenic enzymes
such as malic enzyme, fatty acid synthase, glucose-6
phosphate dehydrogenase and 3-hydroxy-3-methyl-
glutaryl-CoA (HMG CoA) reductase 7.
Keywords:
Garlic,
Obese mice,
Anorexigenic effect
Correspondence to Author:
A. Osonuga
School of Medical Sciences, University
of Cape Coast, Cape Coast, Ghana

Djankpa et al., IJPSR, 2012; Vol. 3(5): 1364-1366 ISSN: 0975-8232
Available online on www.ijpsr.com 1365
It was also suggested that garlic lowers serum lipids by
delaying lipid absorption from gastrointestinal tract
and diminishing LDL cholesterol synthesis in the liver.
Garlic also increases the body’s metabolic rate by
stimulating the adrenal gland to release adrenaline
which increases the rate of fat metabolism in the body
and in turn helps burn more calories to decrease
weight 8. Some researchers have proved that regular
addition of garlic to diet can help reduce blood
cholesterol and glucose levels 9, 10, 11.
This work is aimed at investigating the weight reducing
effects of garlic in obese mice.
MATERIAL AND METHODS: The genetically modified
obese mice and non-obese mice were obtained from
Noguchi Memorial Institute, Accra. Nine mice (six of
which were obese) were used in this study and
grouped into three. Groups A and B were made of 3
obese mice each whereas group C consisted of 3 non-
obese mice. For group A and group C mice, 20 ml
aqueous garlic extract was added to their feed daily
whereas no garlic was added to the feed of group B
mice.
The aqueous garlic extract was prepared from locally
available garlic bulbs in accordance to the method
used by Mahesar et al 10. Body weight was measured
using a weighing balance while fasting blood glucose
level was determined using the OneTouch Select
glucometer. The blood sample was taken from the tail
vein. The study was carried out over a period of 44
days during which the weight and blood glucose were
measured weekly and the average for each was
computed. Data analysis was done using SPSS-V15. The
data were presented as Mean + SD with statistical
analysis carried out using student’s t-test and ANOVA.
Difference were considered to be statistically
significant at error probability of less than 0.05
(p<0.05)
RESULTS:
TABLE 1: WEEKLY MEAN WEIGHT (g)
GROUP
MEAN WEIGHT
P- VALUE
BEFORE
AFTER
A
38.7  2.89
20.7  1.15
0.013*
B
30.3  0.58
44.3 2.08
0.005*
C
21.3  1.15
22.0  0.00
0.423
*p value < 0.05 was statistically significant
There was statistically significant decrease in mean
weight in group A mice and significant increase in body
weight in group B mice. Group C mice didn’t show any
significant variation in body weight.
TABLE 2: WEEKLY MEAN GLUCOSE LEVELS (mmol/l)
GROUP
MEAN GLUCOSE LEVEL
P- VALUE
BEFORE
AFTER
A
6.5  0.44
5.3  0.15
0.029*
B
6.9  0.57
6.8  0.68
0.667
C
5.3  0.98
5.2  0.93
0.130
* p-value <0.05 was considered statistically significant.
There was a statistically significant decrease in blood
sugar levels in group A mice. The decrease in sugar
levels in group B and C were not statistically significant.
DISCUSSION: Results obtained on weight in this study
agree with research conducted by two researchers 7, 10
who suggested that garlic causes a reduction in BMI.
This reduction in body weight is probably due to the
action of allicin, a potent compound in crushed garlic
that increases the body’s metabolic rate by stimulating
the adrenal gland to release adrenaline which
increases the rate of fat metabolism in the body and in
turn helps burn more calories and decrease weight 8.
The significant weight loss observed in group A may
also be due to the fact that, sulphur-containing
compounds in garlic acted on the hypothalamus of the
obese mice, increasing the sensitivity of the hypo-
thalamus to leptin, a hormone secreted by fat cells in
the body, which functions by impinging its receptors in
the hypothalamus altering the set point at which
satiety is reached, so that the organism eats less 10. We
also observed that group A ate less compared to group
B. Hence, the mean weight of the group A was
significantly lower.
Comparing the mean weight of group C to that of
group A, garlic had a significant weight loss effect on
group A than group C. Group C did not significantly
reduce in weight because they probably had reduced
blood circulating leptin 9. Hence, the weight loss effect
of garlic was less compared group A. Garlic may have
served other systemic and cardiovascular functions
such as antithrombotic, antibiotic, antiglycative, anti-
inflammatory, hypolipidemic, hypo-cholesteremic,
anti-atherosclerotic, hypoglycemic and hypotensive

Djankpa et al., IJPSR, 2012; Vol. 3(5): 1364-1366 ISSN: 0975-8232
Available online on www.ijpsr.com 1366
activities, rather than reducing weight significantly in
the normal mice 9, 10, 11 .
Our results confirm the findings that garlic has a
hypoglycemic effect on obese mice that fed on garlic 9,
10, 11. The hypoglycemic effect may be due to the
presence of flavonoids and sulphur-containing
compounds in the garlic extract 10. Garlic may
potentiate insulin effect on plasma by increasing
secretion of insulin from beta cells of the pancreas 7.
This elevated insulin level causes a decrease in blood
glucose. Allicin, the principal bioactive compound in
garlic extract also has a scavenging effect on excess
glucose stored as fat. Some of the excess glucose is
also converted to ATP 7.
On the other hand, the decrease in the mean glucose
level of group B and group C was insignificant (p >
0.05).
CONCLUSION: The results from this study showed that
regular administration of garlic to obese mice for 44
days significantly decreased blood glucose level by
18.5% and body weight by 46.5%. This observation
may be useful in diet modification for obese human
subjects by nutritionists and dieticians.
REFERENCES:
1. R.H. Miller: Eat Garlic For Weight Loss. Retrieved from
http//EzineArticles.com. 20th November, 2010 at 18:34 GMT.
2009
2. N.E. Marieb and H. Katja: Anatomy and Physiology. 7th Edition.
Pearson Education Inc, USA. 2007
3. A.H. Moldket, M. K. Serdula , W.H. Dietz, et al: The spread of
the obesity epidemic in the United States, 1991–1998. JAMA
1999, 282, 1519–1522
4. E. Isganaitis, and H.R. Lustig: Fast food, Central nervous system,
Insulin resistance and Obesity. Arteriosclerosis, Thrombosis and
Vascular Biology, 2005, 25, 2451.
5. J.S. Mcphee, R.V. Lingappa, and F.W. Ganong: Pathophysiology
of Disease: An Introduction To Clinical Medicine. 5th Edition.
McGraw- Hill Publication, USA. 2006, Pages 552-556.
6. V. R. Considine, K. S. Madhur, L. M. Heiman, K. Aidas, W. T.
Stephens, R. M. Nyce et al: Serum Immunoreactive-Leptin
Concentrations in Normal-Weight and Obese Humans. N Engl J
Med., 1996 334 (5): 324-325.
7. E.Y. Sukandar, H. Permana, I.K. Adyana et al: Clinical Study of
Turmeric (Curcuma longa L.) and Garlic Extracts as
Antihyperglycemic and Antihyperlipidemic agent in Type-2
Diabetes-Dyslipidemia Patients. Science Alert. 2010
8. M. Noaki, N. Takeshi, U. Mitsuyasu, I. Nagatoshi, T. Hidekatsu
and H Minoru: Garlic as an antifatique agent. Mol. Nutr. Food
Res., 2007, 51, 1329- 1334.
9. H. Drobiova, M. Thomson, K. Al-Qattan, R. Peltonen-shalaby, Z.
Al-Amin and M. Ali: Garlic increases Antioxidant Levels in
Diabetic and Hypertensive Rats determined by a Modified
Peroxidase Method. Oxford Journals 2009
10. 0 H. Mahesar, M.A. Bhutto, A.A. Khand, N.T. Narejo: Garlic used
as an alternative medicine to control diabetic mellitus in
alloxan-induced male rabbits. Pak J Physiol, 2010, 6 (1), 1- 6.
11. C.T. Liu, L.Y. Sheen and C.K. Lii: Does garlic have a role as an
antidiabetic agent? Mol. Nutr. Food Res, 2007, 51, 1353- 1364.
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