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Relationship Between Intake of Green
Tea and Periodontal Disease
Mitoshi Kushiyama,* Yoshihiro Shimazaki,* Masatoshi Murakami,* and Yoshihisa Yamashita*
Background: Green tea is a very popular beverage, and in
vitro studies have shown that green tea polyphenols inhibit
the growth and cellular adherence of periodontal pathogens
and their production of virulence factors. We investigated the
epidemiologic relationship between the intake of green tea
and periodontal disease.
Methods: We analyzed 940 Japanese men aged 49 to
59 years as part of a comprehensive health examination.
Probing depth (PD), clinical attachment loss (AL), and bleed-
ing on probing (BOP) were used as the periodontal parameters.
We examined the relationship between the intake of green tea
and periodontal parameters. The intake of green tea was de-
fined as the number of cups per day in a self-administered
questionnaire.
Results: The intake of green tea was inversely correlated
with the mean PD, mean clinical AL, and BOP. In multivariate
linear regression models, every one cup/day increment in
green tea intake was associated with a 0.023-mm decrease
in the mean PD (P<0.05), a 0.028-mm decrease in the
mean clinical AL (P<0.05), and a 0.63% decrease in BOP
(P<0.05), after adjusting for other confounding variables.
Conclusion: There was a modest inverse association be-
tween the intake of green tea and periodontal disease. J Peri-
odontol 2009;80:372-377.
KEY WORDS
Epidemiology; green tea; periodontal disease; periodontitis.
Periodontal disease is a chronic dis-
ease that is prevalent in adults.
The incidence and progression of
periodontal disease is related causally to
periodontal pathogens,
1,2
as well as to
various host and environmental fac-
tors.
3,4
Eating habits and nutritional
intake affect periodontal disease. Many
studies have reported that consumption
of vitamin C and calcium is linked to
periodontal disease
5,6
and that the con-
sumption of whole-grain and lactic acid
foods has a prophylactic effect on peri-
odontal disease.
7-9
Green tea is a popular drink, and the in-
take of greentea and its components,such
as catechin, had a preventive effect
against cancer development and cardio-
vascular disease in experimental and
epidemiologic studies.
10,11
Several in vi-
tro studies have suggested that green tea
catechins, such as (-)-epigallocatechin
gallate (EGCg), inhibit periodontal path-
ogens
12-14
and the destruction of peri-
odontal tissue.
15,16
A pilot clinical
study
12
showed that periodontal treatment
withtheslow-releaselocaldeliveryofcate-
chin improved periodontal status. How-
ever, it is not clear whether the daily
intake of green tea has a beneficial effect
on periodontal health. Therefore, we exam-
ined the epidemiologic relationship be-
tween the daily intake of green tea and
periodontal disease through a compre-
hensive health examination in middle-
aged Japanese men.
* Department of Preventive Dentistry, Kyushu University Faculty of Dental Science,
Fukuoka, Japan.
doi: 10.1902/jop.2009.080510
Volume 80 • Number 3
372
MATERIALS AND METHODS
Study Population
More than 95% of the men enlisted in the Self-Defense
Force in Fukuoka, Japan, attended a comprehensive
health examination that included a 5-day admission
to the Self-Defense Force Fukuoka Hospital in the 5
years before retirement. The examination was con-
ducted for preretirement healthcare for the subjects.
We examined a total of 1,123 men aged 49 to 59 years
between January 2000 and March 2002. Of these, 940
subjects who had ‡20 teeth and all of the data required
for analysis were studied to ensure an adequate as-
sessment of periodontal condition. The subjects pro-
vided oral consent to participate in this study. The
study was conducted in accordance with the Helsinki
Declaration, and the design and procedures were ap-
proved by the Self-Defense Force, Fukuoka Hospital,
and the Ground Staff Office.
Measurements
Oral examination was carried out by one dentist
trained to perform a clinical examination of oral health
status using a normal dental chair. Probing depth (PD)
and clinical attachment loss (AL) were measured
using a periodontal probe
†
at the mesio-buccal and
mid-buccal sites for all remaining teeth, except third
molars, following the method of the Third National
Health and Nutrition Examination Survey.
17
Gingival
bleeding on probing (BOP) was evaluated by calculat-
ing the percentage of teeth exhibiting gingival bleed-
ing within a few seconds of probing the periodontal
pockets. The examiner reliability of the periodontal
examination was verified by an intraexaminer calibra-
tion of volunteers; the percentage agreement (within
–1 mm) ranged from 91.0% to 100% for PD and from
89.0% to 100% for clinical AL. The kappa value
ranged from 0.86 to 1.00 for PD and from 0.84 to
1.00 for clinical AL. The examiner was masked to
the answers of the questionnaire while conducting
the periodontal examination.
Each subject completed a self-administered ques-
tionnaire that assessed smoking history, alcohol in-
take, toothbrushing habits, and the daily intake of
green tea; an examiner checked the answers orally.
Smoking habit was quantified as the number of ciga-
rettes smoked per day multiplied by the number of
years smoked. The frequency of toothbrushing was
divided into five categories and coded as follows:
never =1; sometimes =2; once a day =3; twice a
day =4; and three or more times a day =5. We asked
about the habitual frequency of drinking green tea as
the number of cups per day and used it as a continu-
ous variable in the analysis.
Physicians examined each subject’s systemic con-
dition. A blood sample was collected from the antecu-
bital vein after an overnight fast to determine lipid and
glucose levels. The body mass index was defined as
the weight in kilograms divided by the square of the
height in meters. Body fat was defined using foot-to-
foot bioelectric impedance analysis using a body com-
position monitor.
‡
Statistical Analysis
Weused the mean PD,mean clinicalAL, and BOP as de-
pendentvariablestoreflectperiodontaldisease.We cal-
culated the Spearman correlation coefficient among
each periodontal parameter, the intake of green tea,
andotherstudy variables.We used simple linear regres-
sion analysis to examine the relationship between the
intake of green tea and each periodontal parameter.
Stepwise multivariate linear regression analysis was
used to examinethe effect of each independent variable
on the periodontal parameters. The variables for which
the correlation coefficient was significant were entered
into the multivariate model. The statistical analyses
were performed using a software program.
§
RESULTS
The characteristics of the subjects were compared to
the data for men 50 to 59 years old from the National
Nutrition Survey of Japan, conducted in 2000 (Table
1).
18
Most of the data were similar; however, the
subjects’ systolic blood pressure and triglycerides
were slightly lower and the high-density lipoprotein
(HDL) cholesterol was slightly higher compared to
the results of the National Nutrition Survey. The per-
centage of smokers (current and past) was 81.5% in
this study and 76.7% in the National Nutrition Survey.
Table 1 shows the Spearman correlation coefficient
of the study variables. The intake of green tea, smok-
ing habit, number of teeth, and HDL cholesterol were
significantly correlated with all of the periodontal pa-
rameters. The frequency of toothbrushing was associ-
ated with the mean PD and BOP, and the body fat and
triglycerides were associated with BOP. The intake of
green tea was correlated with the frequency of tooth-
brushing and number of teeth. There was no signifi-
cant seasonal variation in mean green tea intake.
The simple linear regression analysis identified a
significant relationship between the intake of green
tea and each periodontal parameter (Table 2). Table
3 shows the results of the stepwise multivariate linear
regression to evaluate each independent variable in
relation to the periodontal parameters. The intake of
green tea was significantly inversely correlated with
all of the periodontal parameters. Every one cup/
day increment in green tea intake was associated with
a 0.023-mm decrease in mean PD (P<0.05), a 0.028-
mm decrease in mean clinical AL (P<0.05), and a
† PCPUNC15, Hu-Friedy, Chicago, IL.
‡ TBF-401, Tanita, Tokyo, Japan.
§ SPSS version 15.0, SPSS Japan, Tokyo, Japan.
J Periodontol • March 2009 Kushiyama, Shimazaki, Murakami, Yamashita
373
0.63% decrease in BOP (P<0.05), after adjusting for
other confounding variables.
DISCUSSION
We conducted a comprehensive health examination
of males in their fifties and examined the relationship
between the daily intake of green tea and periodontal
disease. Most of the subjects in the Self-Defense Force
were men, and men in their fifties have a relatively
large number of existing teeth and a high prevalence
of periodontal disease. The daily intake of green tea
was significantly associated with indices of peri-
odontal disease, including PD, clinical AL, and BOP,
such that the more frequently the subjects drank
green tea, the better was their periodontal condition.
Bacterial biofilm development in the marginal
gingiva and periodontal pockets is important in the
pathogenesis of periodontal disease. Previous in vitro
studies showed that green tea catechin inhibits the
growth of Porphyromonas gingivalis,Prevotella inter-
media, and Prevotella nigrescens
12,14
and the adher-
ence of P. gingivalis onto human buccal epithelial
cells.
14
In addition, green tea catechins with the steric
structures of 3-galloyl radial, EGCg, (-)-epicatechin
gallate (ECg), and (-)-gallocatechin gallate, which
are the major tea polyphenols, inhibit the production
of toxic end metabolites of P. gingivalis.
19
These re-
ports of the inhibitory effects of catechin contained
in green tea on periodontal pathogens may provide
the basis for the beneficial effect of the daily intake
of green tea on periodontal health.
Periodontal disease is an infectious disease involv-
ing gingival inflammation and the destruction of peri-
odontal tissue. Periodontal pathogens, such as P.
gingivalis and Aggregatibacter actinomycetemcomi-
tans (previously Actinobacillus actinomycetemcomi-
tans), produce matrix metalloproteinases (MMPs)
and exhibit collagenase activity.
20
MMPs, such as
Table 1.
Characteristics of Variables and Spearman Correlation Coefficients
Spearman Correlation Coefficient
Mean –SD
(range)
National Nutrition
Survey
18
Mean PD
Mean
Clinical AL BOP
Intake of
Green Tea
Age (years) 52.4 –0.9 (49 to 59) (50 to 59) -0.04 -0.01 -0.03 0.03
PD (mm) 2.5 –0.8 (1.0 to 7.0) – 0.77* 0.69* -0.11*
Clinical AL (mm) 3.0 –1.0 (0.7 to 8.2) 0.77* – 0.50* -0.11*
BOP (%) 17.7 –19.0 (0 to 100) 0.69* 0.50* – -0.08
†
Intake of green tea (cups/day) 3.5 –2.2 (0 to 12) -0.11* -0.11* -0.08
†
–
Smoking habit (pack-years) 23.3 –17.7 (0 to 87.5) 0.24* 0.30* 0.14* -0.06
Alcohol intake (times/week) 4.4 –2.7 (0 to 7) -0.01 -0.03 0.004 -0.04
Toothbrushing frequency (times/day) 3.8 –0.8 (1 to 5) -0.13* -0.02 -0.15* 0.09*
Teeth (n) 26.3 –2.9 (20 to 32) -0.22* -0.35* -0.12* 0.07
†
BMI (kg/m
2
) 23.8 –2.6 (16.6 to 32.8) 23.6 –3.0 0.05 -0.03 0.03 -0.01
Body fat (%) 21.5 –4.4 (10.1 to 35.5) 0.06 -0.004 0.07
†
-0.01
Systolic blood pressure (mm Hg) 128.9 –14.9 (90 to 220) 134.9 –19.5 0.03 0.003 0.05 0.03
Diastolic blood pressure (mm Hg) 82.6 –9.9 (46 to 126) 83.9 –11.7 0.02 -0.05 0.04 -0.02
Total cholesterol (mg/dl) 205.5 –33.1 (99 to 339) 204.0 –36.6 0.01 -0.05 0.05 -0.02
HDL cholesterol (mg/dl) 57.5 –15.9 (23 to 128) 54.1 –15.6 -0.09* -0.11* -0.09
†
0.01
Triglycerides (mg/dl) 149.6 –124.2 (31 to 1,753) 164.3 –161.2 0.05 0.04 0.08
†
0.01
Fasting plasma glucose level (mg/dl) 102.1 –19.2 (74 to 289) 101.7 –29.9 0.04 0.04 0.05 -0.02
–=not applicable.
*P<0.01.
†P<0.05.
Intake of Green Tea and Periodontal Disease Volume 80 • Number 3
374
collagenases and gelatinases, break down the colla-
gen and gelatin that make up the extracellular matrix
of periodontal tissue, and MMP activity plays an im-
portant role in the pathogenesis and progression of
periodontal disease. When periodontal pathogens
live on local periodontal tissue, fibroblasts and mac-
rophages produce several cytokines, including inter-
leukin-1 and -6 and tumor necrosis factor-alpha, as
mediators of the inflammatory response and immune
reaction.
21
These cytokines play a direct role in the
destruction of periodontal tissue and encourage
fibroblasts and macrophages in periodontal tissue
to enhance the production and activation of MMPs, re-
sulting in the progressive destruction of periodontal
tissue.
22
Astudy
13
showed that green tea catechin,
EGCg, and ECg inhibit the activity of P. gingivalis–
derived collagenase. In addition, EGCg inhibited
osteoclast formation in a coculture of primary osteo-
blastic cells and bone marrow cells,
15
and it induced
the apoptotic cell death of osteoclast-like multinucle-
ated cells in a dose-dependent manner.
23
Previous
studies
10,11
suggested that green tea catechin has a
preventive effect against the development of cancer
and cardiovascular disease, and the effect has been
ascribed to the antioxidative mechanisms of cate-
chin.
24,25
Oxidative stress plays an important role
in the pathogenesis of periodontal disease, as well
as many other disorders,
26,27
and it is believed that
antioxidants can defend against inflammatory dis-
eases.
26
Vitamin C is a well-known antioxidant,
28
and reports
5,29
have shown a significant relationship
between vitamin C deficiency and periodontal break-
down. In addition, a recent animal study
30
showed
that the oral administration of vitamin C prevented
alveolar bone resorption by decreasing oxidative
damage to periodontal tissue. Therefore, similar
mechanisms might be involved in the effects of the in-
take of green tea.
Smoking habit and the frequency of toothbrushing,
which are important lifestyle factors for periodontal
Ta b l e 3 .
Parameter Estimates From Stepwise Multivariate Linear Regression Models Evaluating
Each Independent Variable in Relation to Periodontal Parameters
Dependent Variable
Mean PD (mm)
Dependent Variable
Mean Clinical AL (mm)
Dependent Variable
BOP (%)
Independent Variables Coefficient SE PValue Coefficient SE PValue Coefficient SE PValue
Intake of green tea
(cups/day)
-0.023 0.011 0.037 -0.028 0.013 0.035 -0.63 0.27 0.021
Smoking habit
(pack-years)
0.008 0.001 <0.001 0.013 0.002 <0.001 0.096 0.035 0.006
Toothbrushing
frequency (times/day)
-0.072 0.031 0.021 -3.04 0.79 <0.001
Teeth (n) -0.056 0.008 <0.001 -0.12 0.011 <0.001 -0.65 0.21 0.002
Intercept 4.19 0.26 <0.001 6.01 0.29 <0.001 46.24 6.52 <0.001
R
2
for mean PD =0.103, for mean clinical AL =0.193, and for BOP =0.048.
Ta b l e 2 .
Parameter Estimates From Simple Linear Regression Models Evaluating Intake of Green
Tea in Relation to Periodontal Parameters
Dependent Variable
Mean PD (mm)
Dependent Variable
Mean Clinical AL (mm)
Dependent Variable
BOP (%)
Independent Variable Coefficient SE PValue Coefficient SE PValue Coefficient SE PValue
Intake of green tea (cups/day) -0.034 0.011 0.002 -0.046 0.015 0.002 -0.84 0.28 0.002
Intercept 2.65 0.047 <0.001 3.21 0.062 <0.001 20.70 1.14 <0.001
R
2
for mean PD =0.010, for mean clinical AL =0.010, and for BOP =0.010.
J Periodontol • March 2009 Kushiyama, Shimazaki, Murakami, Yamashita
375
disease, were significantly associated with periodon-
tal parameters and were associated with the intake
of green tea in the bivariate analyses. However, when
we entered the green tea intake and these factors si-
multaneously as independent variables into a multi-
variate regression model whose dependent variable
was an index of periodontal disease, the intake of
green tea was significantly associated with each peri-
odontal parameter, independent of other variables.
This shows that the relationship between the intake
of green tea and periodontal disease is independent
of other confounding factors.
The correlation coefficients in this study were gen-
erally small, suggesting that it is difficult to explain
periodontal disease using only a few variables, be-
cause periodontitis is a multifactorial disease. The
sample size in our study was sufficiently large to show
the statistical significance of the relationship between
the intake of green tea and periodontal disease,
but the factors considered in this study were not suffi-
cient to account for periodontal disease. Although a
number of previous studies suggested that the intake
of food and nutrients, such as dairy products,
8,9
whole
grain,
7
fiber,
7
and vitamin C,
5
may affect the preva-
lence of periodontal disease, we did not examine the
intake of foods and supplements other than green
tea. Further studies including a dietary survey are
necessary to identify other important confounders that
explain the relationship between periodontal disease
and the explanatory variables. Our periodontal exam-
ination at the mesio-buccal and mid-buccal sites of
each tooth may have led to bias because we did not
examine the periodontal condition at six sites per
tooth. In some studies
31,32
that have examined the
reproducibility and validity of dietary questionnaires,
reasonable levels of reproducibility and validity were
observed for the intake of tea. Nevertheless, because
we did not assess the validity and reliability of our
self-administered questionnaire, a bias derived from
measurement errors may have affected the study re-
sults. The study design was based on a cross-sectional
model, so the results cannot establish whether the
regular intake of green tea has a beneficial effect on
periodontal disease. Longitudinal studies of the rela-
tionship between the continued intake of green tea
and periodontal disease are required to strengthen
the interrelation. In addition, because our study sub-
jects were males in their fifties, studies of both genders
and a wide range of ages are needed to generalize
the relationship between the intake of green tea and
periodontal disease.
CONCLUSIONS
The present study suggests that there is a modest in-
verse association between the daily intake of green
tea and periodontal disease. Drinking green tea at
meals and breaks is a relatively easy habit to main-
tain, and drinking green tea as frequently as possible
may help to maintain a healthy periodontium. However,
because the observed relationship between the daily
intake of green tea and periodontal disease was
weak, the application of concentrated green tea com-
ponents, such as catechin, may be expected to have
a more beneficial effect on the periodontal condition.
ACKNOWLEDGMENTS
This work was supported by Grants-in-Aid of Scientific
Research (19390541 and 20592458) from the Minis-
tryofEducation,Science,SportsandCultureofJapan,
Tokyo, Japan, and by the department budget of
Kyushu University, Faculty of Dental Science. The au-
thors report no conflicts of interest related to this study.
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Correspondence: Dr. Yoshihiro Shimazaki, Department
of Preventive Dentistry, Kyushu University Faculty of
Dental Science, 3-1-1 Maidashi, Higashi-ku, Fukuoka
812-8582, Japan. Fax: 81-92-642-6354; e-mail: shima@
dent.kyushu-u.ac.jp.
Submitted October 8, 2008; accepted for publication No-
vember 19, 2008.
J Periodontol • March 2009 Kushiyama, Shimazaki, Murakami, Yamashita
377
