Suppressive effects of dietary fiber in yogurt on the postprandial serum lipid levels in healthy adult male volunteers
Biosci. Biotechnol. Biochem., 68 (5), 1135–1138, 2004
Suppressive Effects of Dietary Fiber in Yogurt on the PostprandialSerum Lipid Levels in Healthy Adult Male Volunteers
Shizuki KONDO, Jin-zhong XIAO,y Noritoshi TAKAHASHI, Kazuhiro MIYAJI,Keiji IWATSUKI, and Sadayuki KOKUBO
Food Research and Development Laboratory, Morinaga Milk Industry Co., Ltd., Zama 228-8583, Japan
Received October 24, 2003; Accepted January 19, 2004
This study assessed the effect of partially hydrolyzed
guar gum (PHGG) in yogurt on the elevation ofpostprandial serum lipid levels. Eleven healthy adult
male subjects were given yogurt with or without 6 g of
PHGG in a fat tolerance test as a crossover study.
Supplementation with 6 g of PHGG significantly sup-
pressed the incremental peaks and areas under the
incremental curve (AUIC) of postprandial serum rem-
nant-like lipoprotein particle cholesterol (RLP-C) and
triglyceride (TG). The results suggest the potential of
Very-low-density lipoprotein (mg/dl) 144:1 Æ 26:6
PHGG to reduce the risk of hyperlipemia.
dietary fiber; yogurt; triglyceride; remnant-
1 All values were measured for the pre-intake blood sample (n ¼ 11).
Epidemiological and clinical studies have shown a
However, the suppressive effect of PHGG on the
positive correlation between the elevated serum total
postprandial elevation of serum lipid concentrations
cholesterol (TCH) level and risk of emergence of
coronary artery disease (CAD).1,2) Previous studies have
In the present study, a single-blind, placebo-control-
indicated that the magnitude of the postprandial serum
led, within-subject crossover study was performed to test
triglyceride (TG) and TG-rich lipoprotein responses
the suppressive effect of PHGG in yogurt on the
after a fat-rich meal were greater in patients with CAD
postprandial serum lipid elevation in a fat tolerance
than in individuals without CAD.3,4) Postprandial lipe-
test. The subjects were all healthy adult males with
mia is thus considered to be associated with the
development of CAD. Serum remnant-like particle
280 mg/dl). The characteristics of the subjects are
cholesterol (RLP-C) and other lipoproteins have recently
presented in Table 1. The study was planned and carried
been noted as indices of postprandial lipemia.4) Ap-
out in accordance with the Declaration of Helsinki, and
proaches to reduce the postprandial serum concentra-
the study protocol was approved and controlled by the
tions of RLP-C and TG are thus considered to be
local ethics committee of Morinaga Milk Industry Co.,
Guar gum, a water-soluble dietary fiber, and its
A pilot study, using a randomized, single-blind,
enzymatic hydrolysate (partially hydrolyzed guar gum,
placebo-controlled, within-subject crossover design,
PHGG), have been well demonstrated to be effective in
was conducted. Eleven subjects participated in this
lowering the serum TCH and TG concentrations.6–8) Irie
study. They were instructed not to deviate from normal
et al.9) have reported that the intake of a high-fat meal
enriched with 8 g of guar gum resulted in lower levels of
throughout the experimental period. Each subject was
postprandial serum TG concentration at 2 h and 4 h after
studied on two occasions, on the same day of the week,
food consumption. Yamatoya et al.10) have found that
with an interval of one week between the study days.
the intake of 15 g of PHGG resulted in a significant
During each study week, the subjects were instructed to
suppression of blood glucose in a glucose tolerance test.
follow consistent menus on Monday, Tuesday, and
y To whom correspondence should be addressed. Tel: +81-46-252-3033; Fax: +81-46-252-3044; E-mail: j xiao@morinagamilk.co.jpAbbreviations: AUIC, area under the incremental curve; PHGG, partially hydrolyzed guar gum; TG, triglyceride; RLP-C, remnant-like lipoprotein
particle cholesterol; CAD, coronary artery disease
Postprandial Changes in the Serum Level of TG (a), RLP-C (b), TCH (c), FFA (d), LDL (e) and VLDL (f) after the Administration of Test
) Supplementation of Partially Hydrolyzed Guar Gum (PHGG, 6 g, n ¼ 11).
Significantly different from the control value at the given time, ÃP < 0:05 determined by a paired student’s t-test.
Wednesday. On each Wednesday evening, each subject
Drinking yogurt samples were prepared as described
consumed the same defined dinner of sushi. The subjects
previously,11) using the three cultures of Streptococcus
were then fasted for at least 14 h, but were permitted to
thermophilus, Lactobacillus delbrueckii subsp. bulga-
drink water until the test sample consumption the next
ricus, and Bifidobacterium longum, all of which were
morning. On Thursday morning, the subjects were given
stock cultures of Morinaga Milk Industry Co., Ltd.,
a 300 g portion of test food composed of 200 g of yogurt
Japan. PHGG, provided by Taiyo Kagaku Co., Ltd.,
with or without 6 g of PHGG mixed with 100 g of a fat-
Japan,12) was dissolved in the milk base at a concen-
and cholesterol-rich food. After ingesting the test food,
tration of 3.0% (w/w) before pasteurization. The
the subjects were instructed to rest, not to move much, to
fermented milks were then homogenized aseptically to
refrain from sleeping, and not to consume anything other
make each drinking yogurt sample. A 100-g amount of
than water until the end of the study. Before and 2, 4 and
each yogurt sample had an energy content of approx-
6 h after consuming the test food, the subjects were
imately 50 kcal and contained 3.0 g of protein and 0.6 g
interviewed, and blood samples were taken from the
of milk fat. The fat- and cholesterol-rich food was
prepared from 80 g of milk cream, 12 g of egg yolk
powder and 8 g of water. One hundred grams contained
Postprandial Changes from the Baseline in the Peak, Time
433 kcal of energy, 5.2 g of protein, 43.5 g of fat and
to Peak and Area under Incremental Curve (AUIC) of SerumTriglyceride and RLP-Cholesterol after the Administration of Test
Food Containing Yogurt with or without Partially Hydrolyzed Guar
The analysis of the blood samples was performed by
SRL Co., Ltd., Tokyo, Japan. Serum TCH, free fattyacid (FFA), and TG were measured with a 7450
automatic analyzer (Hitachi Co., Ltd., Tokyo, Japan). Serum very-low-density lipoprotein (VLDL) and low-
density lipoprotein (LDL) were measured with a 7150
automatic analyzer (Hitachi Co., Ltd., Tokyo, Japan).
Serum RLP-C was measured by the method described
Statistical analyses were performed by SAS (version
8.2; SAS Institute, Inc., Cary, NC, USA), each result
being expressed as the mean Æ SEM. Data for the serum
1 Each values is presented as the mean Æ SEM, n ¼ 11. Ã
lipid parameters obtained from the crossover study were
Significantly different from the control value.
fitted to a two-period crossover model. The effects ofsequence, period, and treatment were examined by using
AUIC values of serum TG (85%, P ¼ 0:0330) and RLP-
two-way crossover ANOVA. The value of each peak
C (77%, P ¼ 0:0158) were observed in the 6 g of PHGG
and the time required to reach each peak for both
group, as compared with the control group. Marked
postprandial serum TG and RLP-C were averaged as the
increases in serum VLDL (peak value of the control
incremental peak and time to the peak, respectively. The
group, þ39:5%; and of the 6 g of PHGG group, þ53:3%
area under the incremental curve (AUIC) of the
against the initial values) and FFA (peak value of the
postprandial serum TG and RLP-C concentrations above
control group, þ43:5%; and of the 6 g of PHGG group,
the baseline plotted 2, 4 and 6 hours after consumption
þ62:1% against the initial values), a slight decrease in
was geometrically calculated by using the trapezoidal
serum LDL (peak value of the control group, À10:5%;
rule and is expressed as mgÁh/dl. In this calculation, any
and of the 6 g of PHGG, À12:8% against the initial
serum concentration that fell beneath the baseline level
values), and little change in serum TCH (peak value of
was calculated as zero. A two-sided t-test was con-
the control group, À2:8%; and of the 6 g of PHGG
ducted, with a significance level set at P < 0:05.
group, À4:4% against the initial values) were observed
All the subjects were in good health throughout the
during the postprandial period; however, PHGG supple-
study period, and none complained of diarrhea or other
mentation had no statistically significant effect on these
discomfort after the consumption of any of the test
variables. There was no significant sequential effect or
foods. The average body weight of each subject
period effect on the incremental peak, time to peak, or
measured on each study day did not change significantly
AUIC in this study. These results clearly indicate the
during the study period (data not shown).
ability of a small quantity of PHGG to reduce the
Figure 1 shows the postprandial changes in serum TG
postprandial serum TG and RLP-C concentrations.
(a), RLP-C (b), TCH (c), FFA (d), LDL (e) and VLDL
In addition, a single-administration study was con-
(f) in the crossover study. The serum TG and RLP-C
ducted by giving yogurt supplemented with 3 g of
concentrations increased markedly during the postpran-
PHGG to nine of the eleven subjects employed in the
dial period (peak values for the control: þ84:8% and
crossover study. A suppressive effect close to that of the
þ73:1%; and for 6 g of PHGG: þ84:0% and þ57:9% for
6 g of PHGG administration in the crossover study was
TG and RLP-C against the initial values, respectively).
observed on the postprandial elevation of the serum TG
Higher peak levels of serum TG and RLP-C were
and RLP-C concentrations (data not shown).
observed 2 h after consumption than 4 h after. The intake
Postprandial lipemia is generally considered to result
of 6 g of PHGG in yogurt resulted in a significant
from delayed digestion due to a low level of lipoprotein
suppression of the peak levels of serum TG and RLP-C,
lipase activity, this causing high levels of serum TG and
as compared with the intake of the control yogurt (Figs.
chylomicron; in some cases, the elevated levels will
1a and 1b). The suppressive effect of the 6 g of PHGG
continue for hours after food consumption. The sup-
was still detectable after 4 h but had disappeared 6 h
pressive effect of guar gum on the postprandial serum
after the test food consumption. Compared with the
TG concentrations is suggested to have been due to the
control levels, the incremental peaks of serum TG and
influence on the fat absorption rate, the site and route of
RLP-C in the subjects consuming 6 g of PHGG were
fat absorption, and the formation and removal rates of
reduced to 88% (P ¼ 0:0681) and 76% (P ¼ 0:0303),
TG-rich lipoproteins.9) In the present study, the effect of
respectively (Table 2). The time to the peak value of
6 g of PHGG was evident on the peak levels as well as
serum TG in the subjects consuming 6 g of PHGG
AUICs of serum TG and RLP-C, and although not
tended to be delayed slightly but not significantly in
significantly, on the time to peak which were also
comparison with the control group. Significantly lower
slightly delayed. These results indicate that PHGG
affected the rate and speed of fat absorption more than
Koskinen, P., and Manninen, V., Helsinki heart study:
TG removal from the serum. PHGG has a branched
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Yamatoya, K., Kuwano, K., and Suzuki, J., Effects of
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We wish to thank K. Yoshida of Nutritional Science
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Laboratory, Morinaga Milk Industry Co. Ltd. for his
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