Original Article

診療と新薬 2017; 54: 986‑993

Eﬃcacy of Burdock Tea in Healthy Japanese witha Tendency for Constipation:

診療と新薬 WebA Randomized, Placebo-controlled, Double-blind Crossover Study

Masatomo NAJIMA 1）／ Akinobu MIYATA 2）／ Shu TAKAYANAGI 3）／
Takahiko HADA 3）／ Junji INOUE 3）● Abstract
Objective: 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 improves bowel movement.
Methods: A randomized, placebo-controlled, double-blind crossover study was conducted to verify the
improvement of bowl movement. In this study we carried out subjective reporting consisting of the questions
Frequency of bowel movement , Days of defecation and Volume of stool as the primary outcome. As forthe secondary outcome, the state of stool ( Scent of stool , Color of stool , and Texture of stool ) was
evaluated. Frequency of bowel movement is the amount of times one defecated during 2 weeks, Days ofdefecation is the number of days in which defecation occurred during 2 weeks.
Results: 24 subjects were randomly assigned to intervention groups and made a start with testing. None werewithdrawn, and a total of 24 (male: 11, female: 13) subjects completed the study. According to the result of
Bowel movement, after the ingestion of the test product the intergroup analysis showed a signiﬁcant diﬀerencein Volume of stool in BG group compared to Placebo group. As for the intragroup analysis, there was asignificant difference in Frequency of bowel movement , Days of defecation , Volume of stool , andTexture of stool in BG group, whereas Frequency of bowel movement and Days of defecation inPlacebo group. No adverse eﬀect associated with the test product was observed in the course of the reporting.
Conclusion: We found out that the ingestion of Burdock tea containing inulin and chlorogenic acid for 2 weeks
contributed to the improvement of bowel movement such as volume of stool. In addition, no safety-related
matter occurred during the test period.
Key Words: Burdock tea, inulin, chlorogenic acid, Polyphenols, Constipation, bowel movement

1. INTRODUCTION
Many Japanese are said to be distressed by constipation.
According to the Comprehensive Survey of Living
Conditions conducted by Ministry of Health, Labor andWelfare in 2013, about 4.7 million Japanese have asymptom of constipation1). This number corresponds to
one in 26 Japanese people, and it shows quite a lot ofJapanese have a problem of bowel movement in someform. It is said that one of the reasons for this problem isthe softened water in Japan; although it is well-known
that minerals have functions of stimulating the intestinal
peristalsis and improving bowel movement2), the water inJapanese rivers is low on the quantity of minerals since
rapid streams deprive the water a chance to gain enoughminerals from the soil at the bottom of rivers. In addition,
it is also reasonable to believe that the recent switch ofJapanese dietary habit from grain and plant-based style tomeat-based style (i.e. Western style) is possibly a reason
as to why constipation has become an issue. Although
research has shown that the ﬁbers included in grains orvegetables increase the frequency of bowel movement3),
it is considered that the recent Japanese diet lacks theamount of fibers and this fact is casting a negative
influence on bowel movement. Furthermore, several
other factors inherent in the environment of recent Japansuch as stress or lack of exercise are believed to improve
the troubles related to bowel movement4).
Constipation generally refers to the condition of having
a diﬃculty in defecating, and it is often diﬃcult to judge
whether he/she suﬀers from constipation since the stool
frequency or the defecation state vary considerably by
individual. Typically, the problem of bowel movement isoften derived from the decrease of intestinal functions

1）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

〈pre-observation
period〉

診療と新薬・第 54 巻

第 10 号（2017 年 10 月）〈1st intake
period〉〈Wash out〉

2 weeks

2 weeks
BG

Placebo

2 weeks

2 weeks〔Group B〕〈2nd intake
period〉
2 weeks

2 weeks〔Group A〕

67 （987）

Placebo

BG

Visit 2Visit 1

ReportFigure 1 Trial design

due to the breakdown in lifestyle habits or stress, rather
than the malfunction of defecation caused by illness. This
problem also triggers the subjective symptoms such as
feeling frustrated , difficulty to sleep and/or being
lazy about work or housekeeping , all of whichsignificantly affect one s QOL (Quality of Life) 5) 6) .
Needless to say, it is important to change lifestyle habits(such as increasing the amount of exercise) or reducing
stress in order to improve bowel movement. In addition,
it is also effective to actively ingest nutrition such as
dietary fiber (that recent Japanese are said to lack), or
nutrition which stimulates the intestinal functions. In
fact, a variety of food products are available on themarket that promote the improvement of bowel
movement. Among them, there are products of Burdock(Arctium lappa L.): it is rich in dietary ﬁber and has been
known as the food warming our body and improving thecondition of stomach since old times. Therefore, it is oneof the foods which should actively be consumed by the
person who wants to improve their bowel movement.
Since Burdock is plentiful in ingredients such as a watersoluble dietary ﬁber called inulin and polyphenols which
provide an anti-oxidant action7) 8), it is easily speculated
from these ingredients that its ingestion improves bowel
movement. However, comparatively burdensome
preparations such as removing soil on the surface orskimming oﬀ the scum when cooking are needed in orderto eat Burdock, and these preparations make busy
contemporary people avoid ingestion of this food. Also,
some people do not like its unique taste or texture.
Burdock tea is one of the solutions for the aboveexplained hurdles to ingest it. It is tea consisting of theextracted ingredients from Burdock, and therefore
enables us to easily ingest Burdock in everyday life. In
this study, we conducted a randomized, placebocontrolled, double-blind crossover study to verify theefficacy of Burdock tea for the improvement of bowel
movement, by using healthy Japanese as 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 crossoverstudy was conducted with the aid of a fund from
AHJIKAN CO., LTD. (Hiroshima) at Japan Clinical Trial
Association (JACTA, Tokyo). The study implementation
period was 8 weeks, from October 23rd, to December 18th,
2016. The study consisted of pre-observation period (2weeks), intake period Ⅰ (2 weeks), wash out period (2weeks), and intake period Ⅱ (2 weeks) (Figure 1).
This study was conducted in accordance with the ethicalprinciples of the declaration of Helsinki. The study
protocol was approved by the Institutional Review Boardof Pharmaceutical Law Wisdoms (Tokyo). Written
informed consent was obtained from all subjects. The
allocation of the test product to the subjects was carriedout by the person in charge of allocation. The allocation
list was sealed by the person in charge of allocation andstrictly controlled in a safe deposit box of JACTA until
the end of the study. This trial was registered at UMIN
Clinical Trial Registry (Trial ID: UMIN000024765).
2.2. Subjects
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 September through October, 2016.
2.2.1. Inclusion criteria(1) Healthy males and females aged between 30 and 59
years;(2) Individuals with a tendency for constipation;
The doctor conducting the present study confirmed
subjects were not of ill health.
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;68 （988）

診療と新薬・第 54 巻

(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 of 138 applicants, 114 were eliminated according
to the exclusion criteria. The inclusion criteria wasjudged by the principle investigator. All subjects weresequentially allocated ﬁrst to group A (n=13) and group
B (n=11). In the process of subject assignment, age wastaken into consideration to avoid biased distribution.
Subjects randomly received either the test sample or theplacebo for 2 weeks in a double-blind, crossover fashion.
2.4. Description of test product and blinding
The test product of burdock (Arctium lappa L.) roots was
Baisen- GOBOUCHA ( BG ) containing inulin andchlorogenic acid, prepared by AHJIKAN CO., LTD. The
method of making the tea includes steeping a teabag(dried burdock root 2g) in a kettle of hot water (1L), andbringing to the boil for a few minutes. The subjects wereasked to drink the tea every day once in the morning,
afternoon, and evening (3 times a day). The placebo( Placebo ) was also burdock tea but it is from the driedburdock root which has been boiled. Table 1 (1, 2)
shows the nutritional content of the sample. 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
2 weeks. Subjects were instructed as follows: to avoid
excessive amounts of food, drink or alcohol; to maintain adaily record of intake, frequency of bowel movement,
volume of stool, and state of stool during the test period.
2.5.2. Outcome
The objective of this study was to verify the improvementof bowel movement by drinking the tea containing inulin
and chlorogenic acid.
To evaluate this objective, reporting of Frequency ofbowel movement , Days of defecation , and Volume ofstool were observed as the primary outcome. As for thesecondary outcome, state of stool ( Scent of stool ,Color of stool , and Texture of stool ) was evaluated.
Frequency of bowel movement is the amount of times
one defecated during 2 weeks, Days of defecation is thenumber of days in which defecation occurred during 2
weeks.
Regarding Volume of stool and Scent of stool ,subjects rated every defecation on an ordinal scale of 1 to
5 with higher scores indicating a better result. Then the
average score was calculated during two weeks of preobservation and again during the intake period. Whilst
Color of stool and Texture of stool of every
defecation were classified into 5 categories so that #1
and #5 were graded as +1, #2 and #4 were graded as

第 10 号（2017 年 10 月）

Table 1-1 Nutritional content of the sample
Item
Moisture
Protein
Lipid
Ash
Available carbohydrate
EnergyTable 1-2

Quantity（per 100 ml of tea）
BG

Placebo

100 g
−
−
−
0.1 g
0 kcal99.9 g−−−0.1 g
0 kcal

The lower limit values for management standard
Item

InulinChlorogenic acid

BG (per 1000 ml of tea)
100 mg
1 mg+2, and #3 was graded as +3 (the best possible result).
Then the average score was calculated during two weeks
of pre-observation and again for two weeks during theintake period. Values were compared between preobservation period and intake period in every outcome.
The details are illustrated in Appendix 1.
To evaluate the safety of the test foods, adverse eventswere collected by means of a written questionnaireduring the study.
2.6. Data analysis
Intention-to-treat (ITT) set was adopted in the present
study. The sample size was calculated as 15 participants
with the following settings: statistical power of 0.8, eﬀect
size of 0.8, and signiﬁcance level of p<0.05. All statistics
were expressed as mean ± standard deviation (SD).
Numbers or scores of bowel movement were compared in
the same group (intragroup) and between BG and Placebo(intergroup) by performing a paired t-test. A chi-square
test and Student's t-test were used to compare subject
backgrounds between groups. Multiplicity according tothe occasions was not adjusted. Any subjects withmissing 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 the ＜ 5% level in the twosided test.

3. RESULTS
3.1. Participant demographics
24 subjects were randomly assigned to intervention
groups and made a start with testing. None werewithdrawn, a total of 24 (male: 11, female: 13) subjects
completed the study (Fig 2). The ages were 32-55 year
olds (mean age 44.1± 6.3 years old). Data sets wereanalyzed for evaluations on Group A and B (Table 2).
3.2. Validity of the crossover method
The effects of either intake period for Frequency of診療と新薬・第 54 巻

第 10 号（2017 年 10 月）

69 （989）

Assessed for eligibility（n＝138）〔M:59, F:79〕

Enrollment

Excluded （n＝114）〔M:48, F:66〕¨Did not meet inclusion criteria（n＝114）¨Declined to participate（n＝0）

Randomized（n＝24）〔M:11, F:13〕
Group AGroup B

Allocation
Allocated to Placebo -ﬁrst (n＝11) M:9, F:2〕
¨Received allocated intervention (n＝11）¨Did not receive allocated intervention（n＝0）

Allocated to BG - ﬁrst (n＝13) M:2, F:11〕¨Received allocated intervention (n＝13）¨Did not receive allocated intervention（n＝0）

Follow-Up
Lost to follow-up（n＝0）
Discontinued intervention （n＝0）

Lost to follow-up（n＝0）
Discontinued intervention（n＝0）

AnalysisAnalysed（n＝11 ）〔M:9, F:2〕
¨Excluded from analysis（n＝0）

Analysed（n＝13）〔M:2, F:11〕¨Excluded from analysis（n＝0）

Figure 2 Flow diagram of subject disposition

Table 2 Subject demographics
Item

Unit

Group AGroup B

Subjects
Male : Female
Age *numbers
numbersyears

13
2 : 1145.1 ± 6.1

119:2
43.0±6.7

mean ± SD* No signiﬁcant diﬀerence

bowel movement , Days of defecation , and Volume ofstool were not statistically significant (p=0.403,
p=0.342, and p=0.601, respectively) (Table 3). Thus,
we conclude that the carry-over eﬀect can be ignored andthe result obtained from the crossover design in thepresent study can be evaluated appropriately.
3.3. Bowel movement
Table 4 depicts the results of bowel movement. As forFrequency of bowel movement and Days ofdefecation , no signiﬁcant diﬀerences were yielded in theintergroup analysis, whereas a signiﬁcant diﬀerence wasobserved between the two groups in Volume of stool .
With regard to intragroup analysis, BG showed signiﬁcantdiﬀerences in Frequency of bowel movement , Days ofdefecation , and Volume of stool , whilst significant
differences were found in Frequency of bowel70 （990）

診療と新薬・第 54 巻

第 10 号（2017 年 10 月）

Table 3 Bowel movement of baseline
Bowel movement

Unit

1st period（n ＝ 24）

2nd period（n ＝ 24）

p-value1）

Frequency of bowel
movement

number

9.65±3.66

10.04±4.19

0.403

Days of defecation
Volume of stool

day
score

8.46±2.96
3.60±0.84

8.79±3.07
3.55±0.82

0.342
0.601

Values are expressed mean ± SD
1) between the values of baseline of 1st period and 2nd period

Table 4

Results of bowel movement

Unit

Time point1）
BG（n=24）

Frequency of bowel
movement

numberPre-intake
Post-intake⊿

8.9 ± 3.6
11.1 ± 4.0 **2.3 ± 3.4

8.9 ± 3.6
10.5 ± 4.2 *1.6 ± 3.1

0.551

Days of defecationday

Pre-intake
Post-intake⊿

7.9 ± 2.99.7 ± 2.9 **1.8 ± 2.6

7.9 ± 2.9
9.1 ± 3.1 *1.2 ± 2.20.451

Pre-intake
Post-intake⊿

3.5 ± 0.8
3.9 ± 0.6 *0.3 ± 0.7

3.5 ± 0.8
3.4 ± 0.9
− 0.2 ± 0.6

0.014 #

Item

Volume of stool

score

1）
Placebo（n=24）

P-value2）

Numbers and Scores are expressed as the mean ± SD.
Frequency of bowel movement: the amount of times one defecated during 2 weeks
Days of defecation: the number of days in which defecation occurred during 2 weeks
Volume of stool: the score of each stool during 2 weeks period calculated as an average1）* p ＜ 0.05, ** p ＜ 0.01 against pre-intake.
2）# p ＜ 0.05 between-group diﬀerence in change from baseline.

Table 5Results of the state of stool

Item

Unit

Time point

BG（n=24）

Placebo（n=24）

Scent of stoolscore

Pre-intake
Post-intake⊿

3.3 ± 0.7
3.5 ± 0.7
0.2 ± 0.6

3.3 ± 0.7
3.2 ± 0.7
0.0 ± 0.5

0.109Pre-intake
Post-intake⊿

2.5 ± 0.4
2.5 ± 0.4
0.0 ± 0.3

2.5 ± 0.4
2.5 ± 0.4
0.0 ± 0.3

0.719

Pre-intake
Post-intake⊿

2.4 ± 0.3
2.6 ± 0.4 *0.2 ± 0.3

2.4 ± 0.3
2.5 ± 0.3
0.1 ± 0.4

0.662

Color of stool

Texture of stool

score

score

P-value

Scores are per each stool calculated as an average, and expressed as the mean ± SD.
* p ＜ 0.05, against pre-intake.

movement and Days of defecation of Placebo.
3.4. State of stool
Table 5 depicts the results of the state of stool. As for
Scent of stool , Color of stool , and Texture of stool ,no signiﬁcant diﬀerences were yielded in the intergroup
analysis. With regard to intragroup analysis, BG
represented a significant improvement in Texture ofstool .
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, double-

診療と新薬・第 54 巻

blind crossover study to verify the eﬀects of the Burdocktea (Baisen-GOBOUCHA) containing inulin andchlorogenic acid. The objective of this study was to verify
whether the ingestion of the tea aﬀects the conditions ofbowel movement. As the primary outcome, after theingestion of the test product the intergroup analysis
showed a signiﬁcant diﬀerence in Volume of stool in thetest group (BG), compared to Placebo. In addition, as forthe intragroup analysis, there was a signiﬁcant diﬀerencein Frequency of bowel movement , Days ofdefecation , Volume of stool , and Texture of stool in
BG, as opposed to only Frequency of bowel movement
and Days of defecation in Placebo. In addition, no
adverse effect associated with the test product wasobserved in the course of the reporting.
Main Findings
This study examined the effects of Burdock tea, whichcontains inulin, a type of water soluble dietary ﬁber, andchlorogenic acid, a type of polyphenols. As a result ofingesting the Burdock tea, Volume of stool of BG
signiﬁcantly improved compared to Placebo. On the other
hand, Frequency of bowel movement and Days ofdefecation of BG showed a better result than that ofPlacebo, meanwhile both groups showed some levels ofsigniﬁcant diﬀerence in the intragroup analysis.
The Burdock tea used in this study is the extract of
Burdock (Arctium lappa L.) which is washed, shredded
finely (including its skin) and then roasted. It is wellknown 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 Burdock tea extractedwith hot water has an abundance of these two
ingredients. On the other hand, the mechanism of
defecation is explained as follows. Firstly, digested foods
are brought to the large bowel and their moisture isabsorbed. Then solid foods are forwarded to the anus byintestinal peristalsis, and they are excreted by thedefecation reflex. The digestion of food is closely
associated with intestinal bacteria, the carcass of whichforms almost all parts of stool. Healthy and effectual
intestinal bacterial flora stimulates the intestinal
peristalsis and positively supports bowel movement.
Functional constipation, which is not caused by intestinediseases, is said to occur as a result of malfunction ofautonomic nervous system which inhibits the defecation
reﬂex and intestinal peristalsis. These troubles force thestool to stay in the large bowel for too long and too muchmoisture is absorbed from the stool, which then becomes
too firm to pass through the anus comfortably 12) .
Therefore, it is speculated that for the improvement ofbowel movement, it is necessary to have a healthyfunction of the intestinal peristalsis and make thedefecation reﬂex regularly.

第 10 号（2017 年 10 月）

71 （991）

In this study, after the ingestion of the Burdock tea byhealthy Japanese test subjects, their Volume of stool
significantly increased compared to the Placebo. Also,
the result of the intragroup analysis revealed that
Frequency of bowel movement , Days of defecation ,Volume of stool , and Texture of stool significantly
improved. These results are thought of as the result of
the ingredients contained in the test product. Inulin
included in the Burdock tea is a batch of Fructan of thepolysaccharide, which is a polymer of fructose. It cannot
be decomposed in human digestive organs, and is treatedas a dietary ﬁber since it is metabolized in the microﬂora
of a human s large bowel13). It is reported that inulin has apossibility of increasing the amount of bifidobacteria in
the human colon and changing the composition of themucosa associated ﬂora signiﬁcantly14) 15). There is also areport that it inﬂuences the amount and nature of the end
products of fermentation (i.e. stools) by affecting themetabolic activity of microorganisms in the microﬂora16).
In addition, there is a report that the ingestion of breadwith inulin by Japanese women improved their frequency,
number of times and volume of stool 17). These testﬁndings support the hypothesis that inulin improved thecondition of microflora of the human large bowel,
stimulated the intestinal peristalsis and improved bowel
movement. Furthermore, it is considered that sinceinulin itself is a dietary fiber, it increased the stool
volume, encouraged defecation and shortened thedetention period of food in the bowel18). At the same time,
the fresh roots of burdock contains 0.78% of thepolyphenols with antioxidant activity, and they mainly
consist of chlorogenic acid and caffeic acid19). They arealso included in coﬀee, and there is a report that drinking
coﬀee signiﬁcantly increases the amount of biﬁdobacteria
in the human colon and chlorogenic acid itself also
induces a significant increase in the growth of the
Clostridium coccoides-Eubacterium rectale group that
may act beneficially in the environment of large
intestine20). Therefore, it is thought that the chlorogenic
acid contained in Burdock tea also improves the
microﬂora (at least the C. coccoides-E. rectale group) of
the human large bowel, stimulated the intestinal
peristalsis and improves bowel movement. In addition,
increasing the amounts of bacteria in the intestines
contributes to the increase of the stool itself, since alarge part of stool consists of the remains of the bacteria.
Furthermore, the microflora of the human large bowel
signiﬁcantly aﬀects the state of stool. It is considered thatsince the good condition of microﬂora of the human large
bowel contributes to the scent, color and texture ofstool21), the ingestion of Burdock tea improved the textureof stool.
In this study, Placebo also showed an improvement inFrequency of bowel movement and Days ofdefecation . This can be explained by the fact that since
the condition of functional constipation is significantly

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診療と新薬・第 54 巻

aﬀected by the stress or autonomic nerves, the exaltationof the test is about to be carried out triggered thedefecation reﬂex and increased the frequency of bowel
movement; in other words, it was caused by the placebo
eﬀect22). However, it seems that only the exaltation was
not enough to stimulate the intestinal peristalsis or toincrease the amount of stool. This leads the possibility
that the quality of bowel movement of Placebo such as
the clear feeling after the defecation or the state of stool,
is diﬀerent from that of BG, who improved the conditionof the microﬂora of the human large bowel, increased theamount of stool and stimulated the intestinal peristalsis
by obtaining the ingredients contained in the Burdocktea.
Based upon the discussion above, we can speculate thatthe ingestion of Burdock tea contributed to the increaseof amount of stool and the improvement of bowel
movement.
Secondary Findings
To evaluate the safety of the test product, adverse eventswere collected by means of a written questionnaireduring the study, and no abnormal change caused by thetest product was observed during the ingesting period.
This result indicated the safety of the ingestion of thetest product for the whole test period.
General Information
The condition of bowel movement is one of the key
parameters of health. It is often said that the frequency,
amount or scent of stool represent the patterns of diet,lifestyle or stress situation. According to the study
ﬁnding, females tend to have the problem of constipation
since their muscular strength is weaker and their pelvis
is wider 23), but the Comprehensive Survey of Living
Conditions1) revealed this problem is also seen among
elderly people and men who have problems of irregulardietary habits or stressful situations. Recently there are anumber of books or articles that give guidance on the
improvement of dietary habits or lifestyle habits to tackle
the constipation problem, and a wide variety of laxatives
are sold in the drugstore. Although there are several
types of laxatives, the basic function of the laxatives is
simply stimulating the bowel peristalsis. Therefore, it is
not a fundamental solution for the constipation, and theintestinal environment does not regain its normal
function. Constipation also brings about many physicaltroubles such as abdominal discomfort, bad breath, strong
body odor, headache, shoulder discomfort, chalk mark,swelling and/or fatigue, all of which seriously aﬀect the
QOL24).
From ancient times, tea has been used for relaxation or
stress reduction25). The fragrance of tea positively aﬀects
brain waves and provides a relaxing eﬀect on the brain26).
Also hot tea warms the body and promotes blood
circulation. Therefore, regardless of the type, tea canprovide us a variety of positive eﬀects. The test productis a tea-bag type and is therefore easily ingested. It is

第 10 号（2017 年 10 月）

considered that if we can obtain not only the relaxing
effect but also the effect of improving the condition of
constipation just by adding the Burdock tea to oureveryday tea-drinking habit, we can improve the level of
QOL and live our life more easily and comfortably.
Limitations
Bowel movement tends to be signiﬁcantly aﬀected by themental stress, as the placebo effect occurs. Also, thedefinition of constipation is ambiguous, and it is often
judged by the subjective decision such as a feeling ofincomplete defecation. In addition, it is reasonable thateven though the frequency of bowel movement increases,
if there are still a sense of discomfort or a tight feeling ofstomach, they cannot feel the bowel movement has
fundamentally improved. Furthermore, Japanese have atendency to avoiding talking about excretion (such as
stool) since ancient times. In this study we used a written
questionnaire for collecting the objective data such as thevolume or texture of stool, and the frequency of bowel
movement. However, it is undeniable that the test
subjects could not gather the precise information about
the volume or texture, and eventually the data varied
between individuals. Also, since we did not carry out thequestionnaire for collecting the subjective assessment of
the test subjects, we could not check for conditions suchas a sense of incomplete defecation or a tight feeling inthe stomach after bowel movement. Therefore, it isdesirable for the further study to introduce both theobjective measuring method for checking the conditionsof bowel movement, and the subjective assessment (suchas questionnaire) for evaluating the subjective view
among the test subjects after defecation. We believe they
enable us to carry out more objective and comprehensive
analysis of bowel movement.

5. CONCLUSION
In conclusion, we found out that the ingestion of Burdock
tea containing inulin and chlorogenic acid for 2 weeks
contributed to the improvement of bowel movement suchas volume of stool. 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.

REFERENCES
1) Ministry of Health, Labor and Welfare. Comprehensive Survey of
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young Japanese women. Eur J Clin Nutr 2007 ; 61: 616-22.
3) Yang J, Wang HP, Zhou L, et al: Eﬀect of dietary ﬁber on constipation:a meta analysis. World J Gastroenterol. 2012 ; 18: 7378-83.
4) Khatri PK, Ali AD, Alzadjali N, et al: Frequency of functional
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Bowel movement

#

Item

Choices

Unit

Valuation method1

Frequency ofbowel movement

To be fulﬁlled

Numbers/ 2w

More frequencies
indicating good result2Days of defecation

To be fulﬁlled

Days/ 2w

More days indicating
good result

3Volume of stool *45 grades with higher

1; Below 0.5, 2; 1.0, 3; 1.5,

Score/ 14; 2.0, 5; Over 2.5

defecation

number indicating
good result

Scent of stool

1; Very bad odor, 2; Bad odor,
3; A little bad odor, 4; Not badodor, 5; No bad odor

Score/1
defecation

5 grades with higher
number indicating
good result

5

Color of stool

1; Chestnut color（+1）, 2; Light
brown color（+2）, 3; Mid browncolor（+3）, 4; Dark brown color（+2）, 5; Black（+1）

Score/1
defecation

3 grades with higher
number indicating
good result

6

Texture of stool

1; Hard（+1）, 2; Slightly Hard（+2）, 3; Normal（+3）, 4; Soft（+2）, 5; Liquid（+1）

Score/1
defecation

3 grades with higher
number indicating
good result*: Subjects compared volume to a 5 x 2.5cm cylindrical object and recorded equal to 1 or 2
cylinders etc.

(Table 1-2 of this article was added in April 2018.)