Original Article

診療と新薬 2017; 54: 994‑1003

Anti-obesity Eﬀect of Burdock Tea in Healthy Japanese:
A Randomized, Double-blind, Placebo-controlled Study

診療と新薬 Web

Masatomo NAJIMA 1) ／ Akinobu MIYATA 2) ／ Shu TAKAYANAGI 3) ／Takahiko HADA 3) ／ Junji INOUE 3)● Abstract
Objectives: The objective of this study is to examine how the ingestion of Burdock (Arctium lappa L.) tea,
Baisen-GOBOUCHA ( BG ) containing inulin and chlorogenic acid contributes to an anti-obesity eﬀect.
Methods: A randomized, placebo-controlled, double-blind study was conducted to elucidate an anti-obesity
effect of the tea containing inulin and chlorogenic acid. In this study we measured the visceral fat area,
subcutaneous fat area, Body mass index (BMI), body weight, and body fat percentage as the primary outcome.
We also evaluated the circumference of body parts (the waist, hip, upper arm, and upper leg) as a secondary
endpoint. Furthermore, adverse eﬀects were collected by means of a written questionnaire during the study.
Results: From all of 72 applicants, 29 were eliminated due to not meeting inclusion criteria. The 43 subjects
were randomly assigned to an intervention group and made a start with ingestion. 5 subjects were withdrawn
due to business or fever, and the remaining 38 subjects completed the study. Thus, data obtained with 38
subjects (BG: 18, <M; 8, F; 10>, Placebo: 20 <M; 8, F; 12>) was used for the analysis of eﬃcacy. After
12-weeks of ingestion, BG showed signiﬁcant diﬀerences in BMI (⊿ 0-8w and ⊿ 0-12w) and body weight (⊿0-8 and ⊿ 0-12w) compared to the Placebo. As for the circumference of body parts, BG decreased moresigniﬁcantly than Placebo in ⊿ 0-4w, ⊿ 0-8w, and ⊿ 0-12w. Excluding 12 subjects (M; 8, F; 4) with BMI ≧25.0kg/m2 as well as visceral fat area ≧ 100 cm2, stratiﬁed analysis was applied with 26 subjects. As a result of
the stratiﬁed analysis, the intergroup analysis also showed a signiﬁcant diﬀerence in BMI , body weight ,waist circumference , hip circumference , upper arm circumference , and upper leg circumference in
the BG. No adverse eﬀects were observed after the ingestion of the test product.
Conclusion: We found out that the ingestion of Burdock tea containing inulin and chlorogenic acid for 12
weeks contributed to the prevention of obesity which is explained by the decrease of BMI, body weight, andthe circumference of the waist, hip, upper arm, and upper leg. In addition, no safety-related matter occurred
during the 12-week test period.
Key Words: Burdock tea, inulin, chlorogenic acid, polyphenols, anti-obesity, BMI

1. INTRODUCTION
Recently, advanced countries such as Japan are abundantwith various foods. The dietary proclivity has shiftedfrom foods with plenty of fiber such as vegetables tomeals consisting of meat and fat, and as a result, more
and more people are suffering from obesity caused byovereating. In addition, in recent years people tend to fall
into the obese category due to lack of sleep, lack ofactivity caused by the development of transportation suchas elevators or transport facilities, malfunction of
metabolism due to the development of air-conditioning
technology or disturbance of the autonomic nervous
system caused by a stress-sick society. Obesity can cause
lifestyle-related diseases such as diabetes, hypertension

or dyslipidemia1). As a result, the Japanese government
launched A Basic Direction for Comprehensive
Implementation of National Health Promotion which set
goals of nutrition, dietary habit, physical activity andrecreation, and implemented it as Health Japan 21 from2013 in order to promote public health 2). Therefore,
prevention of obesity plays an important role inmaintaining good health. For the prevention andtreatment of obesity, it is necessary to improve thebalance between appropriate energy intake (diet) andappropriate energy consumption (exercise). Or, we canalso boost energy consumption by stimulating energy
metabolism inside of the body3).
In the current Japanese market, people wish to achieveobesity prevention while minimizing the extent of the1）JACTA (Japan Clinical Trial Association) 2）Nihonbashi M's Clinic 3）AHJIKAN CO., LTD.
Corresponding author: Research & Development Division, AHJIKAN CO., LTD., 5-5-24 Shoko-center, Nishi-ku, Hiroshima-city 733-0833, Japan
E-mail: j-inoue@ahjikan.co.jp

診療と新薬・第 54 巻

change in their current living habit or avoiding strict diet
restriction and exercise. For achieving the above goals,
there are a variety of supplements or weight-loss
methods which stimulate energy metabolism, diminish
appetite or improve bowel movement. Among them,Japanese people can choose the appropriate supplements
or methods suitable for their own lifestyle or preference,and make good use of them for preventing obesity.
Obtaining dietary ﬁber is one of the well-known methods
for achieving the above- explained goals since it can
improve the condition of bowel lipid movement4). On theother hand, it is reported that polyphenols have a functionof improving metabolism5). Burdock (Arctium lappa L.) isa plant rich with those two ingredients, dietary ﬁber andpolyphenols6) 7), and has been enjoyed as a popular, healthy
food by Japanese. However, it also needs someburdensome preparations (such as removing soil on thesurface or skimming oﬀ the scum) for eating, and these
preparations make it difficult for busy contemporary
people to easily ingest it. One of the solutions for thishurdle is to ingest Burdock as Burdock tea , which
consists of its extracted ingredients. It enables us toeasily ingest Burdock in everyday life.
In this study, we conducted a randomized, placebocontrolled, double-blind study to verify the efficacy of
Burdock tea for anti-obesity means, by using healthy
Japanese people as the test subject. At the same time, we
also examined the safety of ingesting the tea.

2. METHODS
2.1. Trial design
A randomized, placebo-controlled, double-blind study was
conducted with the aid of a fund AHJIKAN CO., LTD.
(Hiroshima) at Japan Clinical Trial Association (JACTA,Tokyo). The study period was 12 weeks, from November
12 th , 2016 to February 5 th , 2017. This study was
conducted in accordance with the ethical principles of thedeclaration of Helsinki. The study protocol was approvedby the Institutional Review Board of Pharmaceutical Law
Wisdoms (Tokyo). Written informed consent was
obtained from all Subjects. This trial was registered at
UMIN Clinical Trial Registry (Trial ID: UMIN
000024779).
The allocation of the test product to the subjects was
carried out by the person in charge of allocation. The
allocation list was sealed and strictly controlled in a safe
deposit box of JACTA until the end of the study.
2.2. Subject
Healthy subjects participated in the present study. All of
the subjects in this study were public volunteers who had
enrolled in the monitor bank of CROee Inc. (Tokyo),recruited from October through November, 2016.
2.2.1. Inclusion criteria(1) Healthy Japanese males and females aged between 30
and 59 years;(2) Individuals with Body mass index (BMI) ≧ 20.0 and <第 10 号（2017 年 10 月）

75 （995）

Table 1 Nutritional content of the sample
Item
Moisture
Protein
Lipid
Ash
Available carbohydrate
EnergyQuantity (per 100 ml of tea）
BG

Placebo

100 g
−
−
−
0.1 g
0 kcal99.9 g−−−0.1 g
0 kcal30.0 kg/m2.
2.2.2. Exclusion criteria(1) Subjects with food allergies;(2) Subjects who are pregnant or lactating;(3) Subjects who consume medicinal product which may
inﬂuence the outcome of the study;(4) Subjects who consume food which may inﬂuence theoutcome of the study;(5) Subjects who are judged as unsuitable for the study by
the principle investigator.
2.3. Randomization
From all 72 applicants, 29 were eliminated according to
the exclusion criteria. The inclusion criteria was judged
by the principle investigator. All subjects weresequentially allocated to Group A (n=21, M; 11, F; 10)
and Group B (n=22, M; 8, F; 14) using a random number
table. In the process of subject assignment, backgroundfactors such as gender, age, body height, body weight,
and BMI were taken into consideration to avoid biased
distribution. Subjects in Group A ingested the test sample
and subjects in Group B ingested placebo for 12 weeks.
2.4. Description of test foods and blinding
The test product was Baisen- GOBOUCHA ( BG )containing inulin and chlorogenic acid, prepared by
AHJIKAN CO., LTD. The method of making the tea
includes steeping a teabag (dried burdock root 2g) in a
kettle ﬁlled with hot water (1L), and bringing to the boil
for a few minutes. The subjects were asked to drink thetea every day once in the morning, afternoon, andevening (3 times a day). The placebo ( Placebo ) was
also burdock tea but it is from the dried burdock root
which has been boiled. Table 1. shows the nutritional
content of BG and Placebo (100ml of tea). BG andPlacebo were indistinguishable in viscosity, color, ﬂavor
or taste. Teas were managed by an identiﬁcation symbol.
All involved were blinded.
2.5. Experimental procedures
2.5.1. Experimental protocol
Subjects consumed almost 1L of boiled tea every day for
12 weeks. Subjects were instructed as follows: to takethe assigned tea; to maintain their usual lifestyles andhabits; to avoid excessive amounts of food, drink, andalcohol; to maintain a daily record of every meal eaten

76 （996）

診療と新薬・第 54 巻

Table 2

第 10 号（2017 年 10 月）

Schedule for the study

Term
Item
Informed consent
Selection and/or allocation
Abdominal fat level
Anthropometric measurements
Ingestion of test foods
Log

Screening●●●●

Test period

Pretrial
test

4w

8w

12 w

●
●

●

●

●
●

● : Implementation↔ : Daily practice during the test period

during the test period; and to send the diary to the study
coordinator.
2.5.2. Outcome
The objective of this study is to elucidate the anti-obesity
eﬀect of the burdock tea containing inulin and chlorogenic
acid. To evaluate this objective, the visceral fat area,
subcutaneous fat area, BMI, body weight, and body fat
percentage were measured as the primary outcome.
Moreover, the circumference of body parts (the waist,
hip, upper arm, and upper leg) were evaluated as thesecondary endpoint. Furthermore, adverse events werecollected by means of a written questionnaire during thestudy.
According to the schedule shown in Table 2, we
measured parameters on efficacy and safety. These
assessments were conducted upon pre-intervention andpost-intervention.
2.5.2.1. The abdominal fat level
The abdominal fat level was obtained via the use of CT
images captured by SOMATOM Emotion 16-Slice(Siemens healthineers Japan, Tokyo) at week 0 and 12.
Several CT images around the umbilicus were obtained
and single scan images at the precise point of theumbilicus were used for analysis. The visceral fat areaand subcutaneous fat area were calculated from CT
images using Power View Fat software (Vigoment
Software Corp., Tokyo).
2.5.2.2. Anthropometric measurements
At week 0, 4, 8 and 12, BMI, body weight, and body fat
percentage were scaled by a body composition analyzer,
DF-860 (Yamato Scale Co., Ltd., Hyogo). Furthermore,
the circumference of the waist (at the umbilical level),hip (at the coccyx), upper arm (at the midpoint of rightside), and upper leg (at the midpoint of right side) were
measured using a non-elastic anthropometric tapemeasure.
2.6. Data analysis
A full analysis set (FAS) was adopted in the study and nosample size design was used. All statistics wereexpressed as mean ± standard deviation (SD). For theabdominal fat level, anthropometric measurements,

Student s t-test was used for intergroup comparisons ofchanges from the baseline. Changes from the baseline in
the same group were assessed using paired t-test. A chisquare test and Student s t-test were used to compare
subject backgrounds between groups. Stratiﬁed analysis
was performed with subjects excluding BMI ≧ 25.0 kg/
m2 as well as visceral fat area ≧ 100 cm2.
Multiplicity according to the occasions was not
adjusted. Any subjects with missing values were
eliminated from the analysis. Statistical analyses were
performed using Statcel 4 (Yanai, 2015) and Excel Tokei
2015 (SSRI). The results were considered signiﬁcant at a
<5% level in the two-sided test.

3. RESULTS
3.1. Participant demographics
The 43 subjects were randomly assigned to anintervention group and made a start with ingestion. 5
subjects were withdrawn due to business or fever, andthe remaining 38 subjects completed the study. Thus,
data obtained with 38 subjects (BG: 18 <M; 8, F; 10>,
Placebo: 20 <M; 8, F; 12>) was used for the analysis ofeﬃcacy (Figure 1). There was no signiﬁcant diﬀerence ingender, age, body height, body weight, or BMI between
groups (Table 3). The daily diet and amount of exercise
just one week prior to the test were surveyed. Regarding
those factors, there were no significant differences
between two groups at the baseline (data not shown).
This monitoring was continued during the study. Thatmeans that BG group did not diﬀer in daily diet or amountof exercise during the study.
3.2. Visceral fat area, subcutaneous fat area, BMI,
body weight, and body fat percentage
Table 4 shows the results of test analyses. Significant
diﬀerences were observed between the two groups of thechange in BMI (⊿ 0-8w and ⊿ 0-12w) and body weight(⊿ 0-8 and ⊿ 0-12w), whereas visceral fat area,
subcutaneous fat area, and body fat percentage did not
differ significantly between the groups. As for the
intragroup comparison, BMI (8 and 12w), body weight (8and 12w), and body fat percentage (12w) indicated診療と新薬・第 54 巻

第 10 号（2017 年 10 月）

77 （997）

Assessed for eligibility（n＝72）〔M:31, F:41〕

Enrollment

Excluded （n＝29）〔M:12, F:17〕¨ Did not meet inclusion criteria（n＝29）¨ Declined to participate（n＝0）

Randomized（n＝43）〔M:19, F:24〕
Group AGroup B

Allocation
Allocated to Placebo（n＝22）〔M:8, F:14〕¨ Received allocated intervention（n＝22）¨ Did not receive allocated intervention （n＝0）

Allocated to BG （n＝21）〔M:11, F:10〕¨ Received allocated intervention（n＝21）¨ Did not receive allocated intervention（n＝ 0）

Follow-Up
Lost to follow-up (n＝0)
Discontinued intervention (n＝3)〔M:3, F:0 〕¨ Unexpected business (n＝3)〔M:3, F:0〕

Lost to follow-up (n＝0)
Discontinued intervention (n＝2)〔M:0, F:2 〕¨ Fever (n＝1)〔M:0, F:1〕
¨ Unexpected business (n＝1)〔M:0, F:1〕

AnalysisAnalysed (n＝20)〔M:8, F:12〕¨ Excluded from analysis (n＝0)

Analysed (n＝18)〔M:8, F:10〕¨ Excluded from analysis (n＝0)

Stratiﬁed analysis
Analysed (n＝12)〔M:4, F:8〕
¨ Excluded from analysis (n＝6)¨ ¨ BMI 侒25.0 as well as Visceral fat area 侒100 cm2

Analysed (n＝14)〔M:4, F:10〕¨ Excluded from analysis (n＝6)¨ ¨ BMI 侒25.0 as well as Visceral fat area 侒100 cm2(n＝6)〔M:4, F:2〕(n＝6)〔M:4, F:2〕

Figure 1 Flow diagram of subject disposition

Table 3 Subject demographics
Item

Unit

BG

Placebo

Subjects
Male: Female *numbers
numbers
years
cm
kg
kg/m2

18
8:10
46.6 ± 7.6
165.6 ± 8.2
70.9 ± 9.4
25.8 ± 1.8208:12
45.1±7.9
163.2±7.8
69.4±7.926.0±1.7

Age *Body height *Body weight *BMI *mean ± SD* No signiﬁcant diﬀerence78 （998）

診療と新薬・第 54 巻

Table 4Item

Visceral fat area

Subcutaneous fat area

BMI

Body weight

Body fat percentage

第 10 号（2017 年 10 月）

Abdominal fat level and anthropometric measurements

Unit

Time points

cm2

cm2

2

kg/m

kg

％

Values 1）

P-value 2）

BG（n ＝ 18）

Placebo（n ＝ 20）

Baseline
12-week⊿ 0-12 w

106.8 ± 49.8
98.1 ± 45.7
− 8.8 ± 21.9

104.8 ± 47.9
95.4 ± 45.8 *− 9.4 ± 15.6

0.920

Baseline
12-week⊿ 0-12 w

216.8 ± 65.2
218.3 ± 63.3
1.5 ± 16.2

213.9 ± 48.2
207.7 ± 41.1
− 6.2 ± 21.4

0.224

Baseline
4-week⊿ 0-4 w

25.8 ± 1.8
25.8 ± 1.9
0.0 ± 0.2

26.0 ± 1.7
26.0 ± 1.7
0.0 ± 0.3

0.833

8-week⊿ 0-8 w

25.3 ± 1.9 **− 0.5 ± 0.3

26.1 ± 1.6
0.1 ± 0.5

＜ 0.001 ##12-week⊿ 0-12 w

25.0 ± 1.9 **− 0.8 ± 0.3

26.0 ± 1.6
0.1 ± 0.4

＜ 0.001 ##Baseline
4-week⊿ 0-4 w

70.91 ± 9.43
70.90 ± 9.46
0.01 ± 0.58

69.36 ± 7.94
69.45 ± 8.15
0.10 ± 0.90

0.657

8-week⊿ 0-8 w

69.56 ± 9.45 **− 1.35 ± 0.70

69.74 ± 7.79
0.38 ± 1.19

＜ 0.001 ##12-week⊿ 0-12 w

68.90 ± 9.35 **− 2.02 ± 0.89

69.55 ± 7.89
0.19 ± 1.06

＜ 0.001 ##Baseline
4-week⊿ 0-4 w

33.2 ± 6.7
33.7 ± 6.5
0.5 ± 1.5

34.8 ± 6.4
34.7 ± 6.3− 0.1 ± 0.6

0.092 ‡

8-week⊿ 0-8 w

33.6 ± 6.6
0.4 ± 1.6

34.8 ± 6.1− 0.0 ± 0.9

0.321

12-week⊿ 0-12 w

32.8 ± 6.6 *− 0.4 ± 0.7

34.4 ± 6.4 *− 0.5 ± 0.9

0.810

Values are expressed as the mean ± SD.
1）† p ＜ 0.1, * p ＜ 0.05, ** p ＜ 0.01 against baseline.
2）‡ p ＜ 0.1, ## p ＜ 0.01 between-group diﬀerence in change from baseline.

significant differences from baseline in BG. In Placebo,
Visceral fat area (12w) and body fat percentage (12w)
showed signiﬁcant diﬀerences from baseline values.
3.3. The circumference of body parts
Table 5 depicts the results of the circumference of thewaist, hip, upper arm, and upper leg. As for thecircumference of body parts, BG decreased moresignificantly than Placebo in ⊿ 0-4w, ⊿ 0-8w, and ⊿0-12w.
3.4. Stratiﬁed analysis
Excluding 12 subjects (M; 8, F; 4) with BMI ≧ 25.0 kg/
m 2 as well as visceral fat area ≧ 100 cm 2, stratified
analysis was applied with the remaining 26 subjects.
Table 6 depicts the results of the stratiﬁed analysis of thevisceral fat area, subcutaneous fat area, BMI, bodyweight, and body fat percentage. Signiﬁcant diﬀerenceswere observed between the two groups of changes in
BMI (⊿ 0-8w and ⊿ 0-12w) and body weight (⊿ 0-8 and⊿ 0-12w). The results of the stratified analysis of thecircumference of body parts are indicated in Table 7. As
for the circumference of waist, hip, upper arm, and upper
leg, BG changed more significantly than Placebo in alltime points.
3.5. Safety
No adverse eﬀects associated with the test product wereobserved in the course of the reporting.

4. DISCUSSION
We conducted a randomized, placebo-controlled, doubleblind study for examining the anti-obesity effect of

診療と新薬・第 54 巻

Table 5
Item

Waist

Hip

Upper arm

Upper leg

Unit

cm

cm

cm

cm

第 10 号（2017 年 10 月）

79 （999）

The circumference of body parts

Time points

Values 1）

P-value 2）

BG（n ＝ 18）

Placebo（n ＝ 20）

Baseline
4-week⊿ 0-4 w

91.5 ± 6.5
90.1 ± 6.3 **− 1.4 ± 0.5

88.9 ± 6.6
89.1 ± 6.5 †0.2 ± 0.6

＜ 0.001 ##8-week⊿ 0-8 w

89.9 ± 6.4 **− 1.5 ± 0.4

89.5 ± 6.6 **0.6 ± 0.5

＜ 0.001 ##12-week⊿ 0-12 w

89.7 ± 6.3 **− 1.8 ± 0.5

89.5 ± 6.6 **0.6 ± 0.5

＜ 0.001 ##Baseline
4-week⊿ 0-4 w

100.6 ± 3.5
99.4 ± 3.4 **− 1.2 ± 0.4

99.8 ± 3.7
99.9 ± 3.8 *0.2 ± 0.3

＜ 0.001 ##8-week⊿ 0-8 w

99.3 ± 3.5 **− 1.3 ± 0.5

100.0 ± 3.8 **0.2 ± 0.3

＜ 0.001 ##12-week⊿ 0-12 w

99.1 ± 3.5 **− 1.5 ± 0.5

100.0 ± 3.8 **0.2 ± 0.3

＜ 0.001 ##Baseline
4-week⊿ 0-4 w

30.8 ± 2.1
29.6 ± 2.1 **− 1.2 ± 0.5

29.6 ± 2.4
29.7 ± 2.4
0.1 ± 0.3

＜ 0.001 ##8-week⊿ 0-8 w

29.6 ± 2.1 **− 1.3 ± 0.5

29.8 ± 2.4 †0.1 ± 0.3

＜ 0.001 ##12-week⊿ 0-12 w

29.2 ± 2.0 **− 1.5 ± 0.4

29.9 ± 2.4 **0.2 ± 0.3

＜ 0.001 ##Baseline
4-week⊿ 0-4 w

49.3 ± 3.0
48.1 ± 3.0 **− 1.2 ± 0.4

49.2 ± 2.7
49.5 ± 2.8 **0.3 ± 0.4

＜ 0.001 ##8-week⊿ 0-8 w

48.0 ± 3.0 **− 1.3 ± 0.4

49.6 ± 2.7 **0.3 ± 0.5

＜ 0.001 ##12-week⊿ 0-12 w

47.8 ± 3.0 **− 1.5 ± 0.4

49.6 ± 2.7 **0.4 ± 0.5

＜ 0.001 ##Values are expressed as the mean ± SD.
1) † p ＜ 0.1, * p ＜ 0.05, ** p ＜ 0.01 against baseline.
2) ## p ＜ 0.01 between-group diﬀerence in change from baseline.

Burdock tea (Baisen-GOBOUCHA: Burdock tea)
containing inulin and chlorogenic acid. As the primary
outcome, after 12-weeks of ingestion of the test product,
the intergroup analysis showed signiﬁcant diﬀerences in
BMI , body weight , waist circumference , hip
circumference , upper arm circumference , and upper
leg circumference in the BG, compared to the Placebo.
In addition, as a result of the stratified analysis that
excluded the criteria for obesity in Japan8) (BMI ≧ 25 kg/
m2, as well as visceral fat area ≧ 100 cm2), the intergroup
analysis also showed a significant difference in BMI ,body weight , waist circumference , hip
circumference , upper arm circumference , and upper
leg circumference in BG. Moreover, no adverse effectassociated with the test product was observed during the
12-week test period.
Main Findings
This study examined the eﬃcacy of ingesting Burdock tea
containing inulin, a type of water soluble dietary fiber,and chlorogenic acid, a type of polyphenols. After
12-weeks of ingestion, the BG showed a significant
diﬀerence in BMI, body weight and the circumference ofseveral body parts, compared to Placebo. The stratiﬁed
analysis excluding the criteria for obesity in Japan 8)
showed the same results.
The Burdock tea used in this study is an extract of
Burdock (Arctium lappa L.) which is washed, shredded
finely (including its skin) and then roasted. It is well

80 （1000）

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第 10 号（2017 年 10 月）

Table 6 Abdominal fat level and BMI (stratiﬁed analysis)
Item

Visceral fat area

Subcutaneous fat area

BMI

Body weight

Body fat percentage

Unit

Time points

cm2

cm2

2

kg/m

kg

％

Values 1）

P-value 2）

BG（n ＝ 12）

Placebo（n ＝ 14）

Baseline
12-week⊿ 0-12 w

82.9 ± 39.3
83.3 ± 41.2
0.4 ± 12.2

80.9 ± 30.4
73.3 ± 33.3 *− 7.6 ± 12.9

0.120

Baseline
12-week⊿ 0-12 w

211.3 ± 37.7
214.9 ± 39.6
3.6 ± 16.3

219.3 ± 54.0
214.7 ± 43.8
− 4.6 ± 22.7

0.306

Baseline
4-week⊿ 0-4 w

24.9 ± 1.2
24.9 ± 1.2
0.0 ± 0.2

25.3 ± 1.2
25.4 ± 1.4
0.1 ± 0.3

0.451

8-week⊿ 0-8 w

24.5 ± 1.3 **− 0.5 ± 0.3

25.6 ± 1.4 *0.3 ± 0.5

＜ 0.001 ##12-week⊿ 0-12 w

24.2 ± 1.3 **− 0.8 ± 0.4

25.5 ± 1.3 †0.2 ± 0.4

＜ 0.001 ##Baseline
4-week⊿ 0-4 w

66.96 ± 6.62
66.92 ± 6.64
− 0.05 ± 0.67

66.78 ± 6.74
67.05 ± 7.25
0.27 ± 0.88

0.324

8-week⊿ 0-8 w

65.63 ± 6.8 **− 1.33 ± 0.81

67.49 ± 7.11 *0.71 ± 1.15

＜ 0.001 ##12-week⊿ 0-12 w

64.91 ± 6.92 **− 2.05 ± 0.84

67.31 ± 6.90 †
0.53 ± 0.99

＜ 0.001 ##Baseline
4-week⊿ 0-4 w

33.0 ± 6.1
33.8 ± 5.6
0.7 ± 1.8

34.8 ± 6.6
34.8 ± 6.6
0.0 ± 0.5

0.191

8-week⊿ 0-8 w

33.5 ± 5.5
0.5 ± 1.9

35.0 ± 6.3
0.2 ± 0.9

0.630

12-week⊿ 0-12 w

32.7 ± 5.7− 0.4 ± 0.934.4 ± 6.7− 0.4 ± 0.9

0.986

Values are expressed as the mean ± SD.
1）† p ＜ 0.1, * p ＜ 0.05, ** p ＜ 0.01 against baseline.
2）## p ＜ 0.01 between-group diﬀerence in change from baseline.

known that Burdock contains ingredients with a wide
variety of health functions, such as dietary fibers,
polyphenols or oligosaccharide9). Among them, inulin10) (atype of water soluble dietary ﬁber) and chlorogenic acid11)(a type of polyphenols) are easily eluted in hot water,
therefore it is highly possible that the Burdock tea
extracted with hot water has an abundance of these two
ingredients. Placebo is also the same burdock tea but it isfrom the dried burdock root without the addition of inulin
and chlorogenic acid, which are both removed after
decocting the test product.
Obesity is caused by the accumulation of triglycerides
in the human body. The triglycerides are originally fat
and carbohydrates, which are ingested as foods but not
suﬃciently digested. Carbohydrates are broken down intomonosaccharides and then absorbed in the course ofdigestion and absorption. However, if there are excesscarbohydrates such as glucose, they either transform toglycogen by the glycogenesis, or change from fatty acidto triglycerides by the lipogenesis and accumulate in the
body9). Triglycerides are a superior energy source, andtherefore the human body can store any amount of themto prepare for starvation. Also, although fat isaccumulated in the adipose tissue, the excess ingestion of
it causes the accumulation ectopically in other tissues10).
After all, this repetition of accumulation is a trigger forobesity. On the other hand, since the decomposition of
triglycerides is also taken place in the adipocyte, thepromotion of this decomposition is related to theprevention of obesity. For this promotion, it is important

診療と新薬・第 54 巻

Table 7
Item

Waist

Hip

Upper arm

Upper leg

cm

cm

cm

81（1001）

The circumference of body parts（stratiﬁed analysis）

Unit

cm

第 10 号（2017 年 10 月）

Time points

Values 1）

P-value 2）

BG（n ＝ 12）

Placebo（n ＝ 14）

Baseline
4-week⊿ 0-4 w

89.0 ± 4.3
87.8 ± 4.2 **− 1.3 ± 0.4

86.3 ± 5.5
86.5 ± 5.3
0.2 ± 0.6

＜ 0.001 ##8-week⊿ 0-8 w

87.6 ± 4.3 **− 1.4 ± 0.4

86.8 ± 5.4 **0.5 ± 0.4

＜ 0.001 ##12-week⊿ 0-12 w

87.4 ± 4.2 **− 1.7 ± 0.5

86.8 ± 5.4 **0.5 ± 0.4

＜ 0.001 ##Baseline
4-week⊿ 0-4 w

98.9 ± 2.4
97.8 ± 2.3 **− 1.1 ± 0.3

99.2 ± 3.8
99.4 ± 3.9 †0.2 ± 0.3

＜ 0.001 ##8-week⊿ 0-8 w

97.6 ± 2.4 **− 1.3 ± 0.5

99.4 ± 3.9 *0.2 ± 0.3

＜ 0.001 ##12-week⊿ 0-12 w

97.5 ± 2.5 **− 1.5 ± 0.5

99.4 ± 3.8 *0.2 ± 0.3

＜ 0.001 ##Baseline
4-week⊿ 0-4 w30.0 ± 1.9
28.8 ± 1.8 **− 1.2 ± 0.4

29.0 ± 2.2
29.1 ± 2.3
0.0 ± 0.3

＜ 0.001 ##8-week⊿ 0-8 w

28.7 ± 1.7 **− 1.3 ± 0.4

29.1 ± 2.3
0.1 ± 0.3

＜ 0.001 ##12-week⊿ 0-12 w

28.6 ± 1.7 **− 1.5 ± 0.5

29.2 ± 2.3 *0.2 ± 0.3

＜ 0.001 ##Baseline
4-week⊿ 0-4 w

48.7 ± 3.1
47.4 ± 2.9 **− 1.2 ± 0.5

48.9 ± 2.3
49.0 ± 2.4 †0.2 ± 0.3

＜ 0.001 ##8-week⊿ 0-8 w

47.3 ± 2.9 **− 1.4 ± 0.5

49.1 ± 2.4 *0.2 ± 0.4

＜ 0.001 ##12-week⊿ 0-12 w

47.1 ± 2.9 **− 1.5 ± 0.4

49.2 ± 2.4 *0.3 ± 0.4

＜ 0.001 ##Values are expressed as the mean ± SD.
1) † p ＜ 0.1, * p ＜ 0.05, ** p ＜ 0.01 against baseline.
2) ## p ＜ 0.01 between-group diﬀerence in change from baseline.

not only to reduce the amount of ingestion ofcarbohydrates and fat and/or to increase the consumptionof energy by exercise, but also to stimulate the energy
metabolism, such as the decomposition cycle oftriglycerides.
T h e f r e s h r o o t s o f b u r d oc k c o n t a i n 0 . 7 8 % o fpolyphenols with antioxidant activity, and they mainly
consist of chlorogenic acid and caffeic acid11). They arealso included in coffee, and are widely known to havefunctions of inhibiting the elevation of blood sugar level
and/or accumulation of fat 12) 13) . Triglycerides aredecomposed into glycerol and fatty acid by the function oflipase. Then, the decomposition of the fatty acid is used
for the gluconeogenesis in the liver or ATP synthesis of

the muscles. The decomposition or synthesis of fatty
acids in the liver have a close relationship with the ratelimiting enzyme called acetyl-CoA carboxylase (ACC)
which synthesizes malonyl-CoA from acetyl-CoA. The
synthesis of fatty acids are stimulated by the action of
ACC. The ingestion of chlorogenic acid inhibits theactivity of ACC, decreases the amount of malonylCoA and increases the activity of carnitine
O-palmitoyltransferase I (CPT1). Eventually, the aboveexplained mechanism inhibits the synthesis of fatty acidand enhances energy metabolism12) 13). As for chlorogenic
acid, it is reported that the chlorogenic acid activates
AMP-activated protein kinase (AMPK) which controls
glycogenesis 14), stimulates glucose transportation and82 （1002）

診療と新薬・第 54 巻

inhibits gluconeogenesis14). Therefore, it is consideredthat the chlorogenic acid contained in the test product(Burdock tea) hindered the synthesis of fatty acid,promoted the decomposition of fatty acid, controlled theincrease of the postprandial glucose level by suppressing
the new formation of carbohydrates and eventuallyinhibited the accumulation of fat which is transformed
from carbohydrates. On the other hand, Inulin included in
the Burdock tea is treated as the water soluble dietaryﬁber under nutriology. Inulin is a type of fructan of thepolysaccharide, which is a polymer of fructose. It cannot
be decomposed in human digestive capacity, but is ﬁrstly
metabolized in the microﬂora of the human large bowel15).
Inulin has a relatively high water retention capacity,swelling capacity and oil-holding capacity16).It also wraps
around the carbohydrates or fats ingested at the sametime and moves from stomach to small intestine 17).
Eventually, it slows down the speed of absorbing
carbohydrates and suppresses the increase of the
postprandial glucose level18). In addition, inulin has thefunction of normalizing the condition of the microflora,
stimulating the growth of the bifidobacteria population
and/or inducing a stool bulking eﬀect19). The deteriorationof the intestinal environment may lead to the productionof endotoxins and trigger a disorder of energy
metabolism20). There is also a report that the short-chain
fatty acid produced in the microﬂora can improve on lipid
metabolism 21). According to the clinical report, theingestion of inulin decreased the amount of serum
cholesterol and triglycerides22), and this report supportsthat inulin has a function of controlling lipid metabolism23).
Based on the above discussion, it is reasonable tospeculate that the inulin contained in the test product also
contributed to the promotion of the decomposition of
fatty acids and inhibiting the accumulation of fat.
In this study, we could observe the decrease of bodyweight and the improvement of BMI by the ingestion of
the Burdock tea. These results ware possibly producedby the fact that the ingestion of the test productpromoted the digestion of fat (which was supposed to beaccumulated under the normal diet) caused by the fat
accumulation-inhibiting effect 13) , and it lead to thedecrease in body weight and the improvement of BMI. In
addition, it is speculated that the continuous energy
consumption such as the activation of intestinal
environment or stimulation of lipid metabolism
contributed to the decrease of body weight. The
circumference of body parts might have changed as aresult of stimulating digestion of the fat accumulated in
the body parts. However, since the test period was not
sufficient for promoting the significant lipid
decomposition, the test results of subcutaneous fat or
visceral fat did not show a signiﬁcant improvement, there
were still some decreasing tendencies, though. Thistendency is actually speculated from the fact that thestratified analysis excluding the criteria for obesity in

第 10 号（2017 年 10 月）

Japan8) (BMI ≧ 25 kg/m2 as well as visceral fat area ≧100 cm 2) showed the same results as those of all thesubjects. Based upon the discussion above, we canconsider that the ingestion of Burdock tea contributed tothe anti-obesity effect achieved by inhibiting theaccumulation of fat and by promoting the decomposing offat.
Secondary Findings
During the test period, five subjects discontinued thetest. Four of them discontinued due to an unexpectedbusiness matter, the other one stopped the test due toillness (fever) that has both have nothing to do with theingestion of the test product. In addition, the diaries ofthe subjects did not show any adverse events. These
results indicated the safety of the ingestion of the test
product for the 12-weeks test period.
General Information
Obesity can be defined as a state of excessive body fat
accumulation than a prescribed level. Especially Visceralfat obesity , a type of obesity that accumulates excessive
fat around the organs, tends to increase the level ofcholesterol and/or blood glucose level, and also increase
the risk of arterial sclerosis 1). Therefore, obesity is
described as the state with high possibility of physicalfailure which can be a serious obstruction for living ahealthy life, and the state to avoid regardless of how fat
you are24). At the same time, however, for contemporary
people it is diﬃcult to abandon their comfortable life of
having delicious but high-calorie dishes or irregular
habits, and shift their life to a regular and healthier style,just for reaching fat. On the other hand, habits such as
taking supplements or drinking tea with the eﬀect of antiobesity do not require them to change their lifestyle
substantially, and therefore they are a much easier way
for them to continue for a long period. Fortunately,Japanese have been drinking tea since ancient times.
After introducing tea from China, Japanese havecontrived ways to inﬁltrate Japanese society with the teadrinking habits.
The ﬂavor of tea has an eﬀect on the brain waves andgives the feeling of relaxation, and the drinking of hot tea
can also heat up the whole body and promote blood
circulation 25) 26). To sum up, the action of drinking tea
contributes to stress reduction or improvement of one s
physical condition. Since the test product is a tea-bag
type and easily prepared, it can be introduced to our daily
lifecycle without any circumstance. If the introduction ofsuch tea to one s daily life improves the conditions ofbowel movement and/or metabolism, and eventually
preventing obesity, it can contribute to the improvementof the eating habits of overweight individuals for reducing
body weight. In addition, even people with regular bodyweight can make good use of the tea for the maintenanceand enhancement of their health.
Limitations
In this study we examined the anti-obesity effect of the

診療と新薬・第 54 巻

Burdock tea by using BMI or body weight as theoutcome. Generally, body fat gradually accumulates inour excessive caloric intake. The test results showed thedecrease of body weight, whereas there is no signiﬁcantdiﬀerence observed in items such as subcutaneous fat or
visceral fat. Therefore, a longer test period might havebeen needed for obtaining more suﬃcient data to support
the efficacy of this product. On the other hand, in thistest, we advised the subjects to have the dietary life sameas their regular one and let them submit the diary.
However, there is possibly of variation of test results
among the test subjects due to a feeling of tension
stemming from the awareness that they are under
examination. Furthermore, the focus on the otheringredients contained in the Burdock tea in addition to
inulin and chlorogenic acid and the examination of theirfunctional mechanisms can contribute to further
exploring the capability of Burdock tea.

5. CONCLUSION
In conclusion, we found out that the ingestion of Burdock
tea containing inulin and chlorogenic acid for 12 weeks
contributed to the prevention of obesity, which wasproved by the decrease of BMI, body weight and thecircumference of several body parts (waist, hip, upper
arm, and upper leg). In addition, no safety-related matteroccurred during the test period.
CONFLICT OF INTEREST
All parts of this study were funded by AHJIKAN CO., LTD. Junji Inoue,
Takahiko Hada, and Shu Takayanagi are employees. All authors state thatthe study was conducted in the absence of any other relationships that
could be interpreted as a conﬂict of interest.

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