Glycative Stress Research
Online edition : ISSN 2188-3610
Print edition : ISSN 2188-3602
Received : Jan. 26, 2014
Accepted : Mar. 4, 2014
Published online : Mar. 31, 2014

Original Artcle

Effect of a vinegar beverage containing indigestible dextrin and a mixed herbal
extract on postprandial blood glucose levels: A single-dose study.
Masayuki Yagi 1), Akihiko Shimode 1), Kiyoshi Yasui 2), Umenoi Hamada 1), Junko Naito 1),
Yoshikazu Yonei 1)
1) Anti-Aging Research Center/Glycation Stress Research Center, Graduate School of Life and Medical Sciences, Doshisha University
2) Koseikai Yotsubashi Clinic.

Abstract

Objective: In search of a dietary therapy to reduce glycation stress, we investigated the effects of different types of vinegar
beverages on postprandial blood glucose levels.
Methods: A total of 15 Japanese women ate rice (Sato-no-Gohan, 200 g, Sato Foods) as the standard diet and then checked theirblood glucose levels with a self-monitoring blood glucose meter (GT-1670, ARKRAY). Four women with a postprandial rise inblood glucose level of less than 50 mg/dL were excluded from further testing, and a total of 11 women (mean age 48.7 ± 5.4 years)
continued with the study. On the test day, subjects consumed a vinegar beverage containing 2.5g indigestible dextrin and 50 mg
mixed herbal extract (test diet (+)), the test diet deprived of indigestible dextrin (test diet (‒)), or a commercially available black(control diet B) or red (control diet R) vinegar beverage before eating a standard diet and then underwent an oral glucose tolerance
test (OGTT). OGTT results were compared between diet groups. Fibersol-2HTM (Matsutani Chemical Industry) was used as thesource of indigestible dextrin. AG herb mixTM (ARKRAY) was used as the mixed herbal extract and consisted of a mixture of
powdered hot water extracts of Houttuynia cordata, Crataegus laevigata (C.oxyacantha), Anthemis nobilis, and grape leaf (Vitis
vinifera). The study was approved by an appropriate ethical review process.
Results: Intake of test diet (+) with the standard diet resulted in a significantly slower rise in blood glucose level over the first 15
minutes after eating compared to control diets B or R (p < 0.05). In addition, the slope of the blood glucose curve between 1 and 15
minutes after intake of test diet (+) was significantly smaller than that after intake of control diets B or R (p < 0.05). No significant
difference was observed between test diet (+) and test diet (‒). No significant difference was observed between the patterns ofblood glucose change after intake of test diet (‒) or control diets B or R. No significant differences were found in the area under the
blood glucose curve (AUC) among the four groups.
Conclusion: Intake of a vinegar beverage containing indigestible dextrin and a mixed herbal extract before eating rice results ina slower initial rise in blood glucose level than after preprandial intake of a commercially available black or red vinegar beverage.
This effect was probably due to the difference in the amount of carbohydrates (sugars, dietary fiber) contained in these beverages.
The observation that vinegar slows the rise in blood glucose level is consistent with previous reports, although the mechanism ofaction could not be elucidated in the present study. Further study is needed to determine whether the slowed rise in blood glucose
level affects subsequent insulin secretion or leads to a reduction in glycation stress.

KEY WORDS: Glycation stress, vinegar beverage, dietary fiber, postprandial hyperglycemia

Introduction

Glycation stress is a series of reactions triggered whenreducing sugars, organic acids or aldehydes react with proteinderived amino acids to form post-translational modification
products, such as carbonyl compounds, succinyl compounds
or advanced glycation endproducts (AGEs). The accumulationof these products causes stress to cells and tissues andleads to the functional decline of proteins which can bind toAGEs, inducing or aggravating inflammation via cytokine
production 1,2). Glycation stress is considered a major risk
factor for accelerated aging. Although diabetes, including theprediabetic state, is a major predisposing factor for glycation
Glycative Stress Research 2014; 1 (1): 8-13(c) Society for Glycation Stress Research_ 8 _stress, glycation can also occur in the absence of diabetes. This
type of glycation is referred to as normoglycemic glycationand is caused mainly by postprandial hyperglycemia. Other
causes include hypertriglyceridemia, excessive alcohol intake,excessive fructose intake, or uremic toxin 2).
In order to reduce glycation stress and its associatedsymptoms, it is important to identify factors predisposing toand precipitating glycation stress and to develop measures
to reduce these factors. In search of a dietary measure thatprevents postprandial hyperglycemia, we evaluated the effects
of preprandial intake of four different vinegar beverages on
postprandial blood glucose levels.

Yoshikazu Yonei, MD, PhD
Anti-Aging Medical Research Center, Graduate School of Life andMedical Sciences, Doshisha University
1-3 Tatara Miyakodani, Kyotanabe City, Kyoto 610-0321, Japan
Tel & Fax: 0774-65-6394 / Email: yyonei@mail.doshisha.ac.jp

Glycative Stress Research

Methods

Standard diet: 200g of ready-to-eat rice (Sato-no-Gohan,
100% Niigata Koshihikari; Sato Foods 		
Co., Ltd, Niigata, Japan) with 2.5g of riceseasoning (Noritama, Marumiya 		Corporation, Tokyo, Japan).

Subjects

Eligible subjects were selected according to the following
criteria. A total of 15 Japanese women aged 40-60 years with no
impaired glucose tolerance diagnosed within the past year (fastingblood glucose <110 mg/dL) and a body mass index (BMI) of < 30
were recruited. Women taking drugs or supplements that may
affect the blood glucose level, smokers, or those having a shortsleep duration (< 5 hours) were excluded. Those meeting the lasttwo criteria were excluded because these lifestyle factors ar e
known to increase glycation stress 3). Written informed consent toparticipation in the study was obtained from all subjects.

Test diet (+): 120 mL of vinegar beverage containing theindigestible dextrin Fibersol-2H(Matsutani Chemical Industry Co., Ltd, Hyogo,
Japan) and a mixed
herbal extract, AG herbs mix (ARKRAY Inc.,
Kyoto, Japan).
Test diet (‒): 120 mL of vinegar beverage containing AG
herb mix(ARKRAY Inc., Kyoto, Japan).

Study design

This study was conducted between November 2012 andDecember 2012 at Koseikai Yotsubashi Clinic (Nishi-ku, Osaka,
Japan). Subjects consumed only water after 10:00 pm on the day
before the test and underwent the test without taking breakfast.
Blood glucose levels were measured with a self-monitoring blood
glucose meter before and at 15, 30, 45, 60, 90 and 120 minutes
after diet consumption. Self-monitoring of blood glucose was
performed as follows. The subject's fingertip was disinfected withalcohol and then punctured with a puncture device. Blood was
gently squeezed out of the punctured fingertip and then drawn
through the sensor of a self-monitoring blood glucose meter (GT1670, ARKRAY, Kyoto, Japan). Descriptive statistics (mean andstandard deviation) of the blood glucose level and the area underthe blood glucose curve (AUC) were calculated for each dietgroup and compared between groups.Prior to intake of test diets,
subjects consumed the standard diet at two independent occasions
and thereafter were further screened according to the following
criteria. Subjects with less than an average of 50 mg/dL increasein blood glucose level after intake of the standard diet compared
to baseline values were excluded. At least 11 subjects (mean age
48.7 ± 5.4 years) were selected to minimize variation in values.
The standard, test, and control diets were administered bya unified method proposed by the Japanese Association for the
Study of Glycemic Index, as detailed below:

Control diet B (Black vinegar beverage):
120 mL of Kurozu-de-Genki (Melodian Co.,
Ltd., Osaka, Japan).
Control diet R (Red vinegar beverage):
120 mL of Honcho Zakuro-aji (Daesang Japan
Inc., Tokyo, Japan),pre-diluted to 1:3 with water.
Subjects ate the standard diet (group N) over a period of
10 minutes with 30 chews per bite. Test diet (+) (group T), test
diet (‒) (group T (dextrin-)), black vinegar beverage (group B),
and red vinegar beverage (group R) were consumed within one
minute, followed by the standard diet ( Table 1 ).
Prior to test start on day 1 body height, body weight, bloodpressure, pulse rate, and body composition, as measured bybioelectrical impedance analysis with a body composition
analyzer (BC-118D Tanita Corp., Tokyo, Japan), were
determined. Physical and mental symptoms were evaluatedaccording to a 5-point scale using the Anti-Aging QOL
Common Questionnaire (AAQol), as described previously 4)

Table 1. Study design
Test

Group

Diet content

n

1st

N

Standard diet (Std)

2nd

N

3rd

Test diet 1)

Control diet(+) 2)(‒) 3)

Black vinegar
beverage

Red vinegar
beverageStandard 4)
diet

15

−

−

−

−

○

Std

15

−

−

−

−

○

T

Test diet (+) + Std

11

○

−

−

−

○

4th

B

Black vinegar beverage + Std

11

−

−

○

−

○

5th

R

Red vinegar beverage + Std

11

−

−

−

○

○

6th

T(dextrin-)

Test diet (‒) + Std

11

−

○

−

−

○

1) Containing mixed herbal extract, 2) Containing indigestible dextrin, 3) Deprived of indigestible dextrin, 4) Rice

_ 9 _

Effect of single-dose vinegar beverage on postprandial blood glucose level

Composition of the standard, test, and control diets
The composition of the standard, test, and control diets
are shown in Tables 2 - 5, respectively. Indigestible dextrin, an
ingredient of test diet (+), has been associated with diarrhea
and other gastrointestinal symptoms when consumed in large
amounts at a time. Given that the maximum non-effect level forindigestible dextrin to cause diarrhea in women is 1.0 g/kg, thedose of indigestible dextrin was set at 2.5 g/120 mL vinegar
beverage in this study.
AG herb mixTM contained in the test diets is a mixture of
powdered hot water extracts of herbs belonging to different
taxonomic groups, including Houttuynia cordata, Crataegus
laevigata (C.oxyacantha), Anthemis nobilis, and grape leaf
(Vitis vinifera). This herbal mixture has been shown to inhibit
AGE production in vitro 6), in a rat model of diabetes 6), and inclinical studies 4,6,7).
The raw materials of the herbal mixture have a long
history as food ingredients and are extracted using hot water,

the same extraction method as used for herb tea. Anthemis
nobilis has been shown to cause an allergic reaction in people
with multiple allergies, albeit at a low frequency. Houttuynia
cordata has been reported to cause photosensitivity andhyponatremia when consumed in large quantities for a longtime as a folk medicine. The test diets used in this study
contained only 50 mg of the herbal mixture in 120 mL vinegar
beverage, and thus were not expected to cause any problems.
Moreover, the safety of the powdered mixed herbal extract
has been demonstrated in various studies, including a lethal
sensitivity test using rec-assay, a reverse mutation test, an acuteoral toxicity study using male and female rats, and an overdose
test in humans (3,000 mg/day, corresponding to 5 times theregular dose, for 4 weeks) 4,6,7).
The control products, Kurozu-de-Genki and Honcho
Zakuro-aji, are commercially available food items with noreported serious adverse reactions, and thus were considered
safe.

Table 2. Nutritional facts of the standard diet.
Rice(Sato-no-Gohan)
200g

Table 4. Nutritional facts of the test diets.

Seasoning(Furikake Noritama)
2. 5 gTest diet (+)

Test diet (‒)

Calories ( kcal )52Protein (g)00Carbohydrate (g)

2.6

0.1

Calories ( kcal )

294

11

Protein ( g )

4.2

0.57

Carbohydrate ( g )

67.8

1

Lipid (g)00Lipid ( g )

0

0.55

Sodium (mg)

19.2

19.2

Sodium (mg)087Table 5. Composition of the control diets(black/red vinegar beverage).

Table 3. Composition of the test diets.
Test diet (+)

Test diet (‒)

Acetic acid (%)

0.35

0.35

Citric acid (%)

0.1

0.1

Indigestible dextrin (%)

2.1−

Mixed herbal extract1) (%)

0.042

0.042

Tien-cha extract2) (%)

0.01

0.01

α-G-rutin (%)

0.01250.0125

Sucralose (%)

0.008

0.008

Acesulfame potassium (%)

0.006

0.006

Salt (%)

0.04

0.04

Condensed tomato juice (%)

0.05

0.05

flavoringwater

flavoringwater

Other ingredients

Kurozu-de-Genki
120 mL

Honcho Zakuro-aji 1)
120 mL

Calories (kcal)

21.6

55.6

Protein (g)00Carbohydrate (g)

5.5

13.7

Lipid (g)00Sodium (mg)00Raw materials

1) Mixed herbal extract contains Anthemis nobilis, Houttuynia cordata,
Crataegus laevigata, and Vitis vinifera of leaf.
2) Tien-cha extract contains Rubus suavissimus.

Pomegranate vinegar(pomegranate concentrate,
apple concentrate, moromi
mash, water-soluble dietaryfiber, carrot concentrate andBlack rice vinegar, apple
fish collagen), fructose,juice, fructose-glucose
dextrin, oligosaccharide,syrup, honey, flavoring,
acidulants (citric acid andsweetener (acesulfame K)
malic acid), flavoring,
sweetener (stevia) andhyaluronic acid (apple isalso contained as a raw
material)

1) Diluted to 1:3 with mineral water_ 10 _Glycative Stress Research

Ethical considerations
This study was conducted at a third-party institution incompliance with the ethical principles based on the Declarationof Helsinki, the Private Information Protection Law and theMinisterial Ordinance on Good Clinical Practice (GCP) for
Drugs (Ministry of Health, Labor and Welfare, Ordinance No.
28 of March 27, 1997). The protocol of the present study wasreviewed for ethical aspects and appropriateness and approved by
the human research ethics committee of the institutional review
board at Tokyo Synergy Clinic (Chuo-ku, Tokyo, Japan). The
study was conducted according to the approved protocol.
The principal investigator and sub investigators, incooperation with a contract research organization, explained thedetails of the study to and obtained written consent from eachsubject before initiating the study.

Statistical analysis

All results were expressed as mean ± standard deviation.
All statistical analyses were performed using IBM SPSS
Statistics 20 software (IBM Japan, Ltd., Tokyo, Japan).
Dunnett's test was used for intergroup comparison of blood
glucose levels, AUC, and the slope of blood glucose curves.
P-values < 0.05 were considered statistically significant.

Results

Subjects had a mean BMI of 23.9 ± 2.4, a body fat ratio of
36.6 ± 4.5%, a systolic blood pressure of 116.8 ± 13.6 mmHg,
and a diastolic blood pressure of 67.4 ± 5.8 mmHg. Subjective
symptoms with the mean score of 3 or more included fourphysical symptoms: eye fatigue, stiff shoulders, easy to gain
weight or to get gray hair, and no mental symptoms. The resultsof blood glucose levels, AUC values, and the slope of the blood
glucose curves in each group are summarized in Table 6.
Blood glucose levels in groups T and N were not different
at any time point. Delta-blood glucose levels, representing thechange from baseline values, were also not different between
groups T and N. No significant difference was observed in any
parameter between groups T and T (dextrin-). In contrast, theblood glucose level and delta-blood glucose level at 15 minutes
after diet intake in group T was significantly lower than that ingroup B ( Fig. 1 ). In addition, the delta-blood glucose level at
15 minutes after diet intake in group T was significantly lower
than that in group R ( Fig. 2 ). No significant difference wasobserved in any parameter between groups T (dextrin-) and B
or between groups T (dextrin-) and R. AUC values showed nosignificant differences in any of the five groups. Finally, theslope of the blood glucose curve between 1 and 15 minutes
after diet intake was significantly smaller in group T than ingroups B and R (p < 0.05). No significant difference was found
for the slope of the blood glucose curve between groups T and
T (dextrin-).

blood glucose level

Table 6. Comparison of blood glucose levels, AUC values, and the slope of blood glucose curves.
Group

T

n = 11
Age 48.7 ± 5.4

mean ± SD

mean ± SD

Dunnett's test
vs．group T

mean ± SD

Dunnett's test
vs．group T

mean ± SD

Dunnett's test
vs．group T

mean ± SD

Dunnett's test
vs．group T

blood glucose level

BR

T (dextrin-)

Before intake

089.2 ± 9.2

91.0 ± 7.8

0.974

93.7 ± 11.5

0.636

92.3 ± 9.3

0.862

87.9 ± 8.9

0.991

15 minafter intake+15

110.7 ± 16.0

108.8 ± 16.0

0.998

130.6 ± 20.0

0.040

129.8 ± 20.6

0.052

103.5 ± 16.4

0.749

30 minafter intake+30

154.2 ± 15.7

159.1 ± 16.3

0.950

167.9 ± 18.4

0.358

165.6 ± 29.9

0.517

146.0 ± 21.0

0.767

45 minafter intake+45

170.6 ± 23.9

169.2 ± 15.3

1.000

168.5 ± 24.4

0.998

160.9 ± 25.4

0.730

156.5 ± 26.4

0.432

60 minafter intake+60

171.7 ± 28.8

163.0 ± 17.9

0.825

158.2 ± 18.4

0.518

158.0 ± 25.6

0.506

157.4 ± 29.9

0.466

90 minafter intake+90

144.9 ± 27.7

144.6 ± 18.2

1.000

137.1 ± 22.4

0.851

136.6 ± 22.6

0.822

144.0 ± 24.9

1.000

+120

133.3 ± 24.8

136.8 ± 15.6

0.979

129.2 ± 20.4

0.967

124.2 ± 17.1

0.6 47135.3 ± 18.2

0.998

Before intake00.0 ± 0.0

0.0 ± 0.0

15 minafter intake+15

21.5 ± 14.1

17.8 ± 13.1

0.933

37.0 ± 12.4

0.044

37.5 ± 17.6

0.035

15.6 ± 12.7

0.730

30 minafter intake+30

65.0 ± 13.8

68.1 ± 12.9

0.981

74.2 ± 13.0

0.552

73.4 ± 26.3

0.632

58.2 ± 18.1

0.773

45 minafter intake+45

81.4 ± 21.8

78.1 ± 14.6

0.989

74.8 ± 20.1

0.871

68.6 ± 26.7

0.421

68.7 ± 19.9

0.424

60 minafter intake+60

82.5 ± 26.8

72.0 ± 17.4

0.672

64.5 ± 16.3

0.224

65.8 ± 28.8

0.279

69.5 ± 24.0

0.501

90 minafter intake+90

55.7 ± 24.8

53.6 ± 17.4

0.999

43.5 ± 28.2

0.582

44.4 ± 27.2

0.644

56.2 ± 21.8

1.000

+120

44.0 ± 20.4

45.8 ± 13.6

0.998

35.5 ± 21.3

0.669

31.9 ± 21.7

0.368

47.4 ± 15.3

0.981

5988.5 ± 2206.7

0.727

6098.2 ± 1430.5

0.822

120 minafter intake

120 minafter intake

Area under the glucose
curve (AUC)

Slope

N

6708.1 ± 1844.7 6382.5 ± 1208.4

0.0 ± 0.00.977

0.0 ± 0.0

6083.5 ± 1758.0 0.811

0.0 ± 0.0

Between before and
15 min after intake

21.5 ± 14.1

17.8 ± 13.1

0.932

37.0 ± 12.4

0.044

37.5 ± 17.6

0.035

15.6 ± 12.7

0.730

Between 15 and30 min after intake

43.5 ± 14.5

50.3 ± 13.9

0.678

37.3 ± 14.5

0.727

35.8 ± 14.7

0.569

42.6 ± 17.3

1.000

Slope of regression linefrom before to 15 and 30
min after intake

32.5 ± 6.9

34.0 ± 6.5

0.982

37.1 ± 6.5

0.552

36.7 ± 13.2

0.632

29.1 ± 9.0

0.773

Data are means ± SD; n ＝11; Dunnett's test. Values in group T were used for comparison.
Abbreviations: group T, test diet (+); group N, standard diet; group B, black vinegar beverage diet; group R, red vinegar beverage diet; group T(dextrin-),test diet without indidestible dextrin_ 11 _

Effect of single-dose vinegar beverage on postprandial blood glucose level

Discussion

120

The objective of this study was to determine whether intakeof test diet (+), composed of vinegar, indigestible dextrin, anda mixed herbal extract, has any effect on postprandial blood
glucose levels. As a result, subjects taking test diet (+) withthe standard diet showed a similar change in postprandial
blood glucose levels as those taking the standard diet alone.
However, over the first 15 minutes after intake test diet (+) led
to a slower rise in blood glucose levels than control diets B or R,
suggesting that test diet (+) slows the rise in postprandial blood
glucose level.

Self-monitored blood glucose

100

80

60

We then attempted to identify the component(s) of test diet(+) responsible for the slow rise in postprandial blood glucose
level. The amount of carbohydrates contained in each vinegar
beverage is as follows: test diet (+): 2.6 g, test diet (‒): 0.1 g,control diet B: 5.5 g, control diet R: 13.7g. Test diet (+) and test
diet (‒) showed no significant differences in their postprandial
effects, indicating that the amount of indigestible dextrin added
had no effect on postprandial glucose levels. Considering theamounts of carbohydrates in the diets, the slowing of the blood
glucose level after a meal by test diet (+) was potentially due tosmaller amounts of sugar contained in test diet (+) as comparedwith control diets B or R.

40
＊
20

0

0

＋15

＋30

＋45

＋60

＋90

＋120

Post-ingestive time (min)Group T

Group B

Fig. 1. Comparison of blood glucose curves between
groups T and B

Data are mean ± SD; .n = 11; Dunnett's test
*p < 0.05: significant difference in slope
Abbreviations: group T, test diet (+); group B, black vinegar beverage
diet

120

Self-monitored blood glucose

100

80

60

40
＊
20

0

0

＋15

＋30

＋45

＋60

＋90

＋120

Post-ingestive time (min)Group T

Group R

Fig. 2. Comparison of blood glucose curves between
groups T and R

Data are mean ± SD; n =11; Dunnett's test
*p < 0.05: significant difference in slope
Abbreviations: group T, test diet (+); group R, red vinegar beverage
diet

Although the mixed herbal extract contains hot water
extracts of Houttuynia cordata, Crataegus laevigata, Anthemis
nobilis, and grape leaf (Vitis vinifera), there has been no
evidence that any of these herbs has any effect on postprandial
blood glucose level. In a previous clinical study 4), no effect on
fasting blood glucose level of the test diet was observed.
Several studies have investigated the effect of acetic acid,the main ingredient of vinegar, on postprandial blood glucose
levels 8-11). A study on the effect of vinegar on the postprandial
blood glucose levels of 13 healthy female college students(mean age 21 years) showed a 30% reduction in AUC after
intake of rice mixed with pure rice vinegar compared to AUC
after intake of rice alone 9) . This effect was particularly
evident in subjects with a postprandial blood glucose levelof > 140 mg/dL after eating rice. A similar effect has also been
observed with apple cider vinegar and tomato vinegar 10) . On
the other hand, another study involving 6 healthy female
students (mean age 22 years) showed no significant difference
between AUC after the intake of a standard diet or a rice plus
vinegar product 11). The absence of a significant difference inthis study may be attributed to the small population size.
Other known effects of vinegar include cholesterollowering effect 12,13) , blood pressure-lowering effect inhumans 14) and rats 15), and iron absorption-promoting effect inrats16). These findings indicate that the acetic acid containedin vinegar slows the absorption of lipids, carbohydrates, andminerals in the gastrointestinal tract.
Vinegar has a long history of consumption as a foodand thus should have no safety concern. Although a highdose administration of acetic acid has been shown to induce
ulcer formation in the stomach 17,18) , studies have shown thatthe intake of a typical amount (20-80 mL) of vinegar does
not cause any adverse events 19-21) . However, since the direct
exposure of teeth to a high concentration of acetic acid maylead to dissolution of tooth enamel 22) , the mouth should be
rinsed after the intake of vinegar. Gargling after vinegar intake
or taking vinegar before a meal is therefore recommended.

_ 12 _Glycative Stress Research

Conclusion

Simultaneous intake of a vinegar beverage containing
indigestible dextrin and a mixed herbal extract with thestandard diet resulted in a slower initial rise in postprandial
blood glucose level compared to the simultaneous intake of acontrol diet (black or red vinegar beverage) with the standard
diet. It is suggested that this effect is due to the difference in theamounts of carbohydrates (sugars - dietary fiber) in the vinegar
beverages consumed.

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The observation that vinegar slows the rise in blood
glucose level is consistent with previous reports, although themechanism of action could not be elucidated in the present
study. Further investigations are needed to determine whether
the slowed rise in blood glucose level affects subsequent insulin
secretion or leads to a reduction in glycation stress.

Conf lict of interest

The authors have no conflict of interest in this study.

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