Consumer health benefits of habitual consumption of chlorogenic acid-enriched coffee: a large single-arm study
Consumer health benefits of habitual consumption of chlorogenic acid-enriched coffee: a large single-arm study Kanae Watanabe
Tohru F. Yamaguchi
Tohru F. Yamaguchi (), Tatsuya Kusaura, Hiroshi Hashimoto,
Mitsuhiro Katashima Health Care Food Research Laboratories Kao Corporation 2-1-3 Bunka
, Sumida-ku Tokyo 131-8501, Japan tel
Yuichi Iwano Food & Beverage Business Unit Kao Corporation 1-14-10 Nihonbashi-Kayabacho
, Chuo-ku Tokyo 103-8210,
Yuji Furui Healthcare Committee Incorporated 1-28-10 Hongo
, Bunkyo-ku Tokyo 113-0033,
Yuji Furui Policy Alternatives Research Institute The University of Tokyo 7-3-1 Hongo
, Bunkyo-ku Tokyo 113-0033,
Abdominal obesity is considered a fundamental cause of metabolic syndrome. It has been reported that continuous consumption of chlorogenic acid, which is a major component of coffee polyphenols, reduces abdominal fat together with body weight in humans. Chlorogenic acid-enriched ready-todrink coffee has been developed recently. The antiobesity function of chlorogenic acid-enriched coffee has been demonstrated in some clinical trials; however, the efficacy of this coffee in daily life, which is more relevant in terms of consumer health, remains unknown. This paper describes a large single-arm study of the acceptability and effectiveness of chlorogenic acid-enriched coffee in terms of weight loss. Participants received one free carton (30 cans) of chlorogenic acid-enriched coffee and were encouraged to consume one can each day, and record their weight and coffee consumption using a web-based weight-recording system. The chlorogenic acid-enriched coffee showed high consumer acceptability. The mean weight change at Week 12 was 1.06 kg (95% confidence interval: 0.96, 1.16). Weight loss was significantly greater in obese participants compared with those with normal body mass index (<25 kg/m2) in both men and women. Changes in weight at Week 12 showed a significant dose-response relationship (p<0.001, n=1659). The habitual consumption of chlorogenic acid-enriched coffee together with the use of a weight-recording system was effective for achieving weight loss in daily life. The popularity of drinking
coffee across all ages suggests a potentially
substantial impact from substituting one cup of coffee a
day with chlorogenic acid-enriched coffee.
Obesity is a serious health problem worldwide [1, 2]
and abdominal obesity is considered a fundamental
cause of metabolic syndrome , which leads to
insulin resistance and a reduction in insulin
secretory function, resulting in the complications of
hyperglycaemia, hypertension and hyperlipidaemia.
Abdominal obesity  is defined as an accumulation
of abdominal body fat, which is determined by the
balance between energy intake and expenditure .
In recent years, many people have struggled to
manage this balance because of the increased availability
of palatable and hedonic foods, such as high-sugar
and/or high-fat foods , leading to a potential
increase in the need for anti-obesity foods.
The prevalence of obesity is not high in the Japanese
population compared with Europe or America .
However, a recent meta-analysis suggested that
compared with Caucasians, a small decrease in insulin
secretory function in East Asians can lead to a large
decrease in the threshold level of insulin resistance,
above which the onset of type 2 diabetes occurs
. East Asians including Japanese tend to be
diagnosed with type 2 diabetes without severe obesity.
Chlorogenic acid is a major component of coffee
polyphenols. Coffee enriched with chlorogenic acid
and with reduced hydroxyhydroquinone, an
oxidant component, has been studied. It was shown
that its metabolites improved vascular endothelial
function, and consequently it reduced blood
pressure in rodents  and in humans [13, 14].
Furthermore, consumption of chlorogenic acid
increases fat utilization in rodents [15, 16] and in
humans . Nagao et al. reported that the
continuous consumption of chlorogenic acid-enriched
coffee reduced body fat, particularly abdominal fat,
together with body weight through increased fat
utilization in humans .
Chlorogenic acid-enriched ready-to-drink (canned)
coffee was developed by Kao Corporation under the
brand name Healthya. It contains 270 mg
chlorogenic acid per can (185 g) with reduced
hydroxyhydroquinone. Regular coffee contains approximately
35175 mg per cup . Canned beverages,
including soft drinks such as fruit juice, carbonated
beverages, green tea and brewed coffee, are very popular
in Japan , and can be easily purchased at many
types of retailer and vending machines. Canned
coffee has the second largest share of the soft drink
market in Japan, after carbonated beverages . A
canned coffee product with an anti-obesity function
is therefore an ideal product to support a
population-based public health strategy .
The anti-obesity function of chlorogenic
acidenriched coffee has been demonstrated in some
clinical trials [17, 18], therefore it has been
approved as a food for specified health use (FOSHU)
by the Consumer Affairs Agency, Government of
Japan, as a part of product development. However,
the efficacy of the coffee in daily life, which is
more relevant in terms of consumer health, remains
unknown. The purpose of this study was to assess
the acceptability and effectiveness of chlorogenic
acid-enriched coffee in terms of weight loss in daily
life through a large single-arm study.
Materials and methods
The test beverage is a canned coffee already on the
Japanese retail market (Healthya coffee) which
contains 185 g of brewed coffee without milk and sugar.
The coffee is brewed from roasted coffee beans using
2.5 times the volume of roasted coffee beans
compared with a conventional brew of coffee, after which
the oxidant components, including
hydroxyhydroquinone, are removed by filtration. The canned
coffee contains approximately 270 mg of chlorogenic
acids, including 5-caffeoyl, 3-caffeoyle, 4-caffeoyle,
3-ferulyl, 4-ferulyl and 5-ferulyl quinic acids, and
approximately 90 mg of caffeine. The coffee has 9 kcal
(37.7 kJ) of energy composed of 0.5 g of protein, 0 g
of fat and 1.9 g of carbohydrate per can.
Pedometer count Walking time
Figure 1 Web-based weight-recording system: (a) web page
for data entry; (b) web page for weight monitoring
Participants were recruited from the general
population, securing a wide variety of Japanese
consumers, using several marketing approaches,
including poster advertisements in trains, flyers on
shop shelves and banner advertising on the
products website. Over 50,000 participants enrolled on
the designated website. All participants were
provided with one free carton (30 cans) of chlorogenic
acid-enriched coffee. Participants were asked to
register the day they received the coffee by clicking
a button on the web-based weight-recording
system provided (Fig. 1). The date of receipt was
considered as Day 1 of the 30-day official monitoring
Participants were asked to consume the chlorogenic
acid-enriched coffee every day for 30 days and to
record their weight and coffee consumption using
the web-based weight-recording system. The system
could record health-related information such as
pedometer count, body-fat percentage estimated
by bioimpedance measurement, exercise activities
and consumption of anti-obesity beverages other
than the coffee to maintain their motivation for
recording. However, these data were not analysed
in the present study. During the 30-day period,
participants were sent eight e-mails to remind them
to drink the coffee and to record the parameters.
Participants were those participants who registered
the date of receipt of the coffee. The following
participants were excluded from the analysis:
participants with particularly low or high weights (<40
kg or 140 kg for men, and <30 kg or 130 kg for
women) , participants with a percentage weight
change 25% or +25%, participants without
baseline weight data and participants with no weight
data other than baseline weight.
A flow chart of the data-gathering procedure is
shown in Fig. 2. All participants agreed to the use
of their data for academic studies through a web
page on the online system.
The weight-recording system remained accessible
after the end of the 30-day monitoring period and
the daily records in the system were evaluated for
a total of 12 weeks after Day 1. We defined the
period from Day 1 to Day 28 as the ad libitum
consumption period, and from Day 29 to Day 84 as
the add-on consumption period. Baseline weight
was defined as the average weight on Days 13.
The weekly average was defined as the average
weight for the subsequent 7-day periods. Where
no weight data were available to calculate the
weekly average, the data were considered as
missing. Statistical analysis was carried out using the
data set defined in Fig. 2.
Using all the available data, the probability of Web
recording of behaviour (PREC), conditional
probabilities of Web recording with coffee consumption
Figure 2 Flow chart showing the data-gathering procedure for statistical analysis
Enrolled over 50,000 consumers
Canned coffee received
and responded (n=30,988)
Assessed by exclusion criteria
(reasons for exclusions were partially duplicated)
No baseline weight: (n=3,030)
No weight data other than baseline: (n=2,243)
Having extraordinary weight data
Men, less than 40 kg: (n=55)
Men, greater than or equal to 150 kg: (n=52)
Women, less than 30 kg: (n=46)
Women, greater than or equal to 140 kg: (n=69)
% Change greater than or equal to +25%: (n=133)
% Change less than or equal to 25%: (n=169)
(PREC|PCONS) and web recording with self-weighing
(PREC|PWEIGH) were estimated individually (n=30,988)
during the 28-day ad libitum consumption period.
We analysed how these variables were mutually
related using graphical modelling .
Statistical analysis was carried out using R statistical
analysis software (Version 3.0.2) . p values <0.05
were considered as significant in two-tailed
statistical tests. Asymptotic confidence intervals (CI)
were indicated as error bars.
The number of participants at the beginning of the
ad libitum consumption period was 25,441, which
fell to 16,928 by Week 4, giving a completion rate
of 66.5%. Most participants dropped out after Week
4, because this was the end of the official
monitoring period. However, many participants continued
to record their coffee consumption and weight and
data were available for 2432 (9.6%) participants at
Week 8 and 1659 (6.5%) at Week 12. The sex ratio
was 4042% women during the ad libitum
consumption period and 3233% during the add-on
Mean body weight decreased monotonically over
the 12-week period (Fig. 3). The mean weight
changes were 0.51 kg (95% CI: 0.49, 0.52), 0.84
kg (95% CI: 0.78, 0.91) and 1.06 kg (95% CI:
0.96, 1.16) at Weeks 4, 8 and 12, respectively
(Fig. 3). The sex ratio, age, baseline body weight
and baseline body mass index (BMI) also differed
significantly between each 4-week period during
the 12 weeks (Table 1). The percentage of women
decreased at each period, while age, baseline body
weight and baseline BMI increased.
Figure 4 shows the mean weight change at Week
12 according to sex and stratified by baseline BMI.
Weight loss was significantly greater in obese
participants compared with those with normal BMI
(<25) in both men and women. A BMI of 2530
kg/m2 is considered overweight and a BMI 30
Meanstandard deviation (SD)
*Some BMI values were missing; #differences between time points were analysed
statistically; 2 test; KruskalWallis test
values are defined as obese and seriously obese,
respectively, by the Japan Society for the Study of
Obesity and the Japanese Government .
Dose-response relationship with weight loss
Consumption of more than 30 cans indicated that
Time course of weight loss. Error bars represent 95%
kg/m2 is considered obese according to the World
the participants had purchased more coffee
Health Organization (WHO) , whereas these selves. The relationship between coffee consump
Body mass index (kg/m2)
Body mass index (kg/m2)
Weight loss stratified by BMI for (a) men and (b) women. The error bars represent 95% confidence intervals. Comparisons
with the normal-BMI groups were made by pooled variance t-tests where p values were adjusted for multiple comparisons
by Dunnetts method. A BMI of 2530 kg/m2 was considered as overweight and a BMI 30 kg/m2 was defined as obese
according to the WHO.
tion and weight change is shown in Fig. 5. There
was a significant dose-response relationship
according to the Jonckheere trend test (p<0.001). Greater
weight loss was observed with increased coffee
consumption over 12 weeks. The maximum mean
weight change of 1.62 kg (95% CI: 1.94, 1.30)
occurred in the highest-dose group (7184 cans).
Subject demographics for each dose group are
presented in Fig. 5. There was no significant difference
in sex ratio, age or baseline body weight according
to the 2 test and KruskalWallis test.
Relationships between Web recording, coffee
consumption and self-weighing
There was a high correlation between PREC|PCONS
and PREC|PWEIGH (0.829; 95% CI: 0.825, 0.832).
Partial correlation coefficients were calculated to
exclude the effect of pseudo-correlations. The partial
correlation coefficients between PREC and PREC|PCONS
with PREC|PWEIGH as a covariate, and between PREC
and PREC|PWEIGH with PREC|PCONS as a covariate were
0.708 (95% CI: 0.700, 0.716) and 0.605 (95% CI:
0.596, 0.613), respectively.
Consumption of chlorogenic acid-enriched coffee
was associated with monotonic weight loss during
the ad libitum and add-on consumption periods,
i.e., 0.51 kg at Week 4, 0.84 kg at Week 8, and
1.06 kg at Week 12. Obese participants lost more
weight than normal-weight participants (Fig. 4).
These results suggest that habitual consumption of
chlorogenic acid-enriched coffee, together with the
use of the weight-recording system, supported
weight loss during daily life, especially in obese
Out of the total of 25,441 participants, 16,928
(66.5%) completed the ad libitum consumption
period, suggesting good acceptability of the coffee
for everyday use, which is an important factor from
a public health perspective. Japanese adults drink
an average of around 11 cups of coffee a week ,
and substituting one cup of coffee a day with
Dose (Number of cans consumed within 12 weeks)
0-14 15-28 29-42 43-56 57-70 71-84
0.97 0.7 0.96 1.2 1.48 1.62
Figure 5 Dose-response relationship for coffee consumption
and weight loss after 12 weeks. Error bars represent
95% confidence intervals. Data are presented
chlorogenic acid-enriched coffee was therefore
assumed to be highly acceptable.
There was a significant dose-response relationship
between coffee consumption and weight loss over
12 weeks (Fig. 5). The mean weight change at Week
12 was 1.62 kg in participants who consumed the
coffee every day (7184 cans in 84 days), which was
similar to the weight loss of 1.5 kg observed in the
earlier 12-week clinical trial . We could not
discriminate between the effects of chlorogenic acid
and caffeine in terms of weight loss from the results
of the present study. However, a placebo beverage
used in an earlier study  was a caffeinated coffee
test beverage, which allows us to infer that the
chlorogenic acid was a major contributing factor.
The significantly greater partial correlation
coefficient between PREC and PREC|PCONS compared with
PREC and PREC|PWEIGH suggests that Web recording
was elicited by coffee consumption, rather than by
self-weighing in the ad libitum consumption period.
However, coffee consumption and self-weighing
were highly associated, implying that drinking
antiobesity coffee might trigger self-weighing;
participants wanted to see the effectiveness of the
product, and self-weighing led in turn to Web recording
to follow weight reduction progress. This series of
behaviours may also help to prevent regaining
weight. In addition, the high completion rate of
the ad libitum consumption period and the fact
that 6.5% (n=1659) of participants continued
voluntary monitoring up to Week 12 suggest that the
weight-recording system that allowed participants
to visualise their behaviour and progress might
help to increase behavioural changes, similar to
the so-called monitoring diet .
There were some demographic differences between
the ad libitum and add-on consumption periods.
The percentage of women was smaller during the
add-on period, resulting in a higher baseline weight
and BMI. This suggests that the motivation for and
dedication to weight loss might differ between men
and women, possibly associated with the fact that
men have a higher prevalence of metabolic
One of the limitations of the present study was
compliance monitoring, owing to the difficulty of
confirming data for such a large number of participants.
However, imprecision in measurement of weight is
not likely to be a serious issue  compared with
most biochemical or physiological measurements.
Furthermore, digital bathroom-type scales are
commonly used at home in Japan, thus the precision is
much higher than with the use of spring-type scales,
which were popular before 2000. A further limitation
was the lack of a control group. However, adopting
the single-arm study design approach enabled us to
enroll a large number of participants from a wide
population, because it was much easier to obtain
their informed consent compared with a randomised
controlled trial design approach.
The observed weight loss within 12 weeks could
be considered to be relatively small (1.06 kg).
However, a meta-analysis of 25 randomised control
trials has estimated that a decrease of 1 kg in body
weight corresponded to decreases of 1.05 and 0.92
mmHg in systolic and diastolic blood pressures,
respectively . Moreover, Japanese people tend to
be diagnosed with type 2 diabetes without
associated severe obesity . These facts suggest that a
small change in body weight in the general
population could have a significant impact on public
health. In addition, the wide acceptability of the
chlorogenic acid-enriched coffee makes this a good
option for those that are unaware of the risk of
diabetes and showing no typical signs of obesity.
Although there was no significant difference in
demographics between dose groups at Week 12, the
habitual consumption of chlorogenic acid-enriched
coffee might not be the only cause of the weight
loss. It is possible that behavioural changes, such
as exercise habits, food selection and eating habits,
might also be related. Further studies are needed
to investigate how lifestyle behaviour may change
in relation to the habitual consumption of
chlorogenic acid-enriched coffee.
The habitual consumption of chlorogenic
acid-enriched coffee together with the use of a
weightrecording system was effective for achieving weight
loss in daily life. Weight loss increased with
increasing coffee consumption over 12 weeks.
Furthermore, the habitual consumption of chlorogenic
acid-enriched coffee triggered self-weighing, which
led to participants Web recording their daily
behaviour. Importantly, this chlorogenic
acid-enriched coffee showed good consumer acceptability.
The popularity of drinking coffee across all ages
suggests a potentially substantial impact of
substituting one cup of coffee a day with chlorogenic
Conflict of interest
This study was supported by Kao Corporation, the
manufacturers of Healthya canned coffee. Kanae Watanabe, Tohru F.
Yamaguchi, Tatsuya Kusaura, Hiroshi Hashimoto, Yuichi Iwano and
Mitsuhiro Katashima are employees of Kao Corporation. Yuji
Furui is also president of Healthcare Committee Inc., which is
partially funded by Kao Corporation.
Human and Animal Rights
All procedures followed were in accordance with the Helsinki
Declaration of 1975, as revised in 2005.
sion in the study.
Informed consent was obtained from all participants for