Psyllium improves dyslipidaemia, hyperglycaemia and hypertension, while guar gum reduces body weight more rapidly in patients affected by metabolic syndrome following an AHA Step 2 diet

Abstract

The aim of this study was to comparatively evaluate the long-term effects of psyllium husk and guar gum supplementation on
metabolic syndrome (MS) components. We randomised 141 MS patients to soluble psyllium husk powder or guar gum 3.5 g t.i.d.
to be taken 20 min before the main 2 meals, or to a standard diet for a cumulative period of 6 months. Both fibres significantly
improved body mass index (−7.2% vs. −6.5%), fasting plasma glucose (−27.9% vs. −11.1%) and insulin (−20.4% vs. −10.8%), HOMA Index (−39.2% vs. −16.7%), glycated haemoglobin (−10.4% vs. −10.3%), low-density lipoprotein cholesterol (−7.9% vs. −8.5%) and apolipoprotein B (−10.5% vs. −5.6%), after 6 months of treatment. Only the psyllium supplementation exerted a significant improvement on plasma triglyceride
concentration (−13.3%) and systolic (−3.9%) and diastolic blood pressure (−2.6%). No significant difference was observed regarding
the standard diet group in comparison to the baseline. On the basis of our data, psyllium could be more strongly indicated
for patients that have to reduce a large number of cardiovascular risk factors, while guar gum could be more rapidly efficacious
in strengthening the effect of diets aimed at reducing body weight.

KeywordsMetabolic syndrome-Soluble fibres-Hypertension-Hypercholesterolaemia-Hypertriglyceridaemia-Hyperglycaemia-Cardiovascular risk

Full text

Mediterr J Nutr Metab (2010) 3:47–54
DOI 10.1007/s12349-009-0056-1
ORIGINAL ARTICLE
Psyllium improves dyslipidaemia, hyperglycaemia and hyperten-
sion, while guar gum reduces body weight more rapidly in patients
affected by metabolic syndrome following an AHA Step 2 diet
Arrigo F.G. Cicero · Giuseppe Derosa · Marilisa Bove ·
Fabrizio Imola · Claudio Borghi · Antonio V. Gaddi
Received: 9 April 2009 / Accepted: 9 June 2009 / Published online: 21 October 2009
© Springer-Verlag 2009
A.F.G. Cicero (쾷)
Atherosclerosis and Metabolic Diseases Research Unit
Internal Medicine, Aging and Kidney Diseases Department
S. Orsola-Malpighi Hospital, University of Bologna
Poliambulatorio Pad. 2
Via Albertoni 15, 40138 Bologna, Italy
e-mail: afgcicero@cardionet.it
G. Derosa
Department of Internal Medicine and Therapeutics
University of Pavia
Pavia, Italy
M. Bove · F. Imola · C. Borghi · A.V. Gaddi
“GC Descovich” Atherosclerosis Research Centre
“D. Campanacci” Clinical Medicine and
Applied Biotechnology Department
University of Bologna
S. Orsola-Malpighi Hospital
Via Massarenti 9, 40138 Bologna, Italy
nificant improvement on plasma triglyceride concentra-
tion (–13.3%) and systolic (–3.9%) and diastolic blood
pressure (–2.6%). No significant difference was observed
regarding the standard diet group in comparison to the
baseline. On the basis of our data, psyllium could be
more strongly indicated for patients that have to reduce a
large number of cardiovascular risk factors, while guar
gum could be more rapidly efficacious in strengthening
the effect of diets aimed at reducing body weight.
Keywords Metabolic syndrome · Soluble fibres · Hyper -
tension · Hypercholesterolaemia· Hypertriglyceridaemia
· Hyperglycaemia · Cardiovascular risk
Introduction
It is well known that a dietetic approach is always beneficial
in the management of cardiovascular disease risk in people
affected by relevant metabolic diseases such as hypercholes-
terolaemia and diabetes, but also at a population level [1].
Increasing dietary fibre has been recommended as a
safe and practical approach for cholesterol reduction [2].
However, “dietary fibre” is a collective term for a variety
of plant substances that are resistant to digestion by
human gastrointestinal enzymes [3]. Dietary fibres can
be classified into two major groups depending on their
solubility in water. The structural or matrix fibres (lignin,
cellulose and some hemicelluloses) are insoluble, where-
as the natural gel-forming fibres (pectin, gums,
mucilages, and the remainder of the hemicelluloses) are
soluble. Studies have focused on soluble fibres such as
oats, psyllium, pectin and guar gum, and qualitative
reviews have suggested that these fibres lower total and
low-density lipoprotein (LDL) cholesterol [4, 5]. Water-
Abstract The aim of this study was to comparatively
evaluate the long-term effects of psyllium husk and guar
gum supplementation on metabolic syndrome (MS) com-
ponents. We randomised 141 MS patients to soluble psyl-
lium husk powder or guar gum 3.5 g t.i.d. to be taken 20
min before the main 2 meals, or to a standard diet for a
cumulative period of 6 months. Both fibres significantly
improved body mass index (–7.2% vs. –6.5%), fasting
plasma glucose (–27.9% vs. –11.1%) and insulin (–20.4%
vs. –10.8%), HOMA Index (–39.2% vs. –16.7%), glycat-
ed haemoglobin (–10.4% vs. –10.3%), low-density
lipoprotein cholesterol (–7.9% vs. –8.5%) and apolipo -
protein B (–10.5% vs. –5.6%), after 6 months of treat-
ment. Only the psyllium supplementation exerted a sig-

insoluble wheat fibre and cellulose have no significant
effect unless they displace foods supplying saturated fats
and cholesterol [6]. Among soluble fibres, psyllium
appears to be the one with the highest antihypercholes-
terolaemic efficacy [7]. Beyond the antihypercholestero-
laemic effect, psyllium appears to also have other posi-
tive effects that could be beneficial for the management
of patients at high cardiovascular risk, such as those
affected by metabolic syndrome (MS). In fact, it showed
a slight antihypertensive effect [8], an antihypergly-
caemic action [9, 10] and a slowing effect on gastric
emptying that is supposed (but not yet demonstrated) to
be beneficial in weight loss dietary regimens [11, 12].
Guar gum appears to have a positive metabolic effect
on cholesterolaemia and insulinaemia [13], and a slowing
effect on gastric emptying [14] as well.
Despite all this intriguing evidence, to the best of our
knowledge, until now no study has considered the effect
of a dietary psyllium supplement on these parameters in
patients affected by MS or directly compared it to any
other kind of fibre in the management of this condition.
For this reason, the aim of our study was to compara-
tively evaluate the long-term effect of a dietary supple-
mentation of psyllium husk and guar gum on a large
range of parameters of MS patients.
Patients and methods
Subjects
One hundred and forty-one age-matched non-smoking
Caucasian patients not taking antihypercholesterolaemic
or antidiabetic treatment, or under stabilised antihyperc-
holesterolaemic and antidiabetic treatment for at least 6
months, who complied with at least three of the follow-
ing criteria were consecutively recruited for the study at
the Atherosclerosis and Metabolic Disease Ambulatory
of the University of Bologna and the Diabetes Center of
the University of Pavia:
- waist circumference: men >40 in (102 cm); women
>35 in (88 cm);
- plasma triacylglycerol (TG) 1.70 mmol/l;
- plasma high-density lipoprotein cholesterol (HDL-
C): men <1.03 mmol/l; women <1.29 mmol/l;
- blood pressure 130/ 85 mmHg or stabilised antihy-
pertensive treatment for at least 6 months
- fasting plasma glucose (FPG) 6.1 mmol/l.
These are the same criteria suggested by the third report
of the Adult Treatment Panel of the National Cholesterol
Educational Program for the diagnosis of MS [15].
Exclusion criteria included:
- severe hyperlipoproteinaemias;
- uncontrolled diabetes;
- active treatments with anticoagulant, anticancer and
antiretroviral drugs; and
- previous cardiovascular disease events.
The study was approved by the University of Pavia
ethical committee and all participants gave their written
consent.
The main baseline demographic, anthropometric and
laboratory characteristics of the subjects are reported in
Table 1.
Study design
During the first month, all patients received dietary advice
(according to Step 2 of the recommendations issued by the
American Heart Association (AHA)) [16] and any nutri-
tional supplement use was eliminated. Then, patients were
randomised to soluble psyllium husk powder (n= 46) or
partially hydrolysed guar gum (n= 46) 3.5 g b.i.d. to be
taken 20 min before the main two meals for 6 months.
These kinds of formulation represent the most widely mar-
keted soluble fibres in Italy. Another group was ran-
domised to continue the AHA Step 2 diet (n= 45).
At baseline, eligible patients received a box contain-
ing a 60-day supply of study medication and were
instructed to start with the first dose of the new medica-
tion on the day after their inclusion in the study. A sec-
ond box containing the study medication was given to
participants at the time of the scheduled control at the 2-
month visit and so on till the end of the study. At each
study visit, patients had to take back the envelopes of
each dose assumed in order to allow us estimate their
compliance to the treatment. They also had to note on a
specific form when and why they eventually did not take
a dose of the product. All medications were provided free
of charge.
The randomisation code was generated by the study
statistician who was the only person allowed to manage the
randomisation list. The randomisation code was broken
only after database lock, but could have been broken for
individual patients in cases of emergency. The randomisa-
tion was made up opening a previously prepared letter con-
taining the randomisation code that assigned the treatment.
A double-blind randomisation was made impossible
because the two fibres have a different colour and flavour.
At each visit, a registered dietician also monitored the
patient’s weight and dietary pattern, through the “Seven-
day questionnaire”, in order to evaluate compliance to
the AHA Step 2 diet [17].
Cuff trough systolic blood pressure (SBP) and diastolic
blood pressure (DBP) was measured using a standard mer-
cury sphygmomanometer (Korotkoff I and V) and a cuff of
48 Mediterr J Nutr Metab (2010) 3:47–54

appropriate size on the right arm with the patient sitting.
Measurements were always taken by the same investigator
in the morning before daily drug intake and after the sub-
ject had been resting for 10 min in a quiet room. The aver-
age of three successive blood pressure readings obtained at
1-min intervals was recorded. Heart rate was monitored at
each clinical visit and was measured after the patient had
been seated for at least 10 min.
Adverse events, intercurrent diseases and compli-
ance were checked at 4-week intervals during the active
treatment phase. Safety monitoring included physical
examination, vital sign assessment, weight and height
measurement, questioning about adverse events and
laboratory tests.
All study procedures followed were in accordance
with the Helsinki Declaration of 1975 as revised in 1983.
Laboratory measurements
The patients entered the research unit between 08:00 and
09:00, after a 12-h overnight fast. All collected samples
were transported within 4 h to a central laboratory at the
authors’ hospital.
A total of 15 ml of blood was collected. Plasma was
obtained by centrifugation at 1000 gfor 25 min at 4°C
and was tested for total cholesterol (TC) and TG concen-
trations using standardised enzymatic methods (TC,
CHOD-PAP; TG, TG without free glycerol; HITACHI
737; Hitachi, Tokyo, Japan). Determination of HDL-C
was performed after the precipitation of 1006 g/ml bot-
tom infranatant with dextran sulphate–magnesium chlo-
ride [18]. LDL-C was estimated by Friedewald’s formula
(LDL-C = TC–HDL-C–TG/5). The interassay coeffi-
cients of variation were 2.7% for TC, 9.1% for HDL-C
and 2.0% for TG. ApoAI and Apo B were measured
using immunoturbidimetric assays (Boehringer-
Mannheim, Mannheim, Germany); the inter- and intraas-
say CsV were 3% to 5%, respectively [19]. Lipoprotein
(a) was measured by a sandwich enzyme-linked
immunosorbent assay (ELISA) method, insensitive to the
presence of plasminogen, using the commercial kit
Macra-Lp(a) (SDI, Newark, DE, USA) [20]; the intra-
and interassay CsV of this method were 5% and 9%,
respectively.
Plasma glucose was tested by the hexokinase/glu -
cose-6-phosphate dehydrogenase method using a
COBAS Mira Plus autoanalyser (Hoffmann–La Roche,
Basel, Switzerland) [21]. The interassay coefficient of
variation for glucose was 3.0%. Insulin was determined
using Phadiaseph Insulin radioimmunoassay (Pharmacia,
Uppsala, Sweden) [22]. HbA1c was measured by
49
Mediterr J Nutr Metab (2010) 3:47–54
Table 1 Characteristics of the subjects affected by the MS after the first month of AHA Step 2 diet and before randomisation
Psyllium group Guar group Step 2 AHA diet group
Number of subjects 48 (M/F = 1) 48 (M/F = 1) 45 (M/F = 0.9)
Age 58.4 ± 2.5 57.9 ± 1.8 57.2 ± 2.1
Body weight 80.2 ± 4.1 79.9 ± 4.5 80.1 ± 4.3
Body Mass Index 28.8 ± 1.5 28.6 ± 1.3 28.5 ± 1.6
Waist circumference (cm) 100.4 ± 10.3 101.7 ± 9.5 102.0 ± 8.3
Glycated haemoglobin (%) 6.7 ± 0.6 6.8 ± 0.7 6.6 ± 0.9
Fasting plasma glucose (mmol/l) 6.1 ± 1.2 6.0 ± 1.3 6.1 ± 1.3
Fasting plasma insulin (μU/ml) 25.2 ± 5.1 24.9 ± 5.8 25.0 ± 5.5
HOMA Index 7.4 ± 2.9 7.2 ±2.5 7.2 ± 2.8
Total cholesterol (mmol/l) 4.83 ± 0.6 4.94 ± 0.6 4.8 ± 0.7
LDL-cholesterol (mmol/l) 2.9 ± 0.3 3.0 ± 0.4 3.0 ± 0.3
HDL-cholesterol (mmol/l) 1.1 ± 0.13 1.2 ± 0.1 1.1 ± 0.1
Triacylglycerols (mmol/l) 1.8 ± 0.3 1.7 ± 0.2 1.7 ± 0.3
Apolipoprotein AI (mg/dl) 130 ± 18 129 ± 16 129 ± 14
Apolipoprotein B (mg/dl) 105 ± 22 107 ± 25 106 ± 20
Lipoprotein (a) (mg/dl) 17.1 ± 7.7 15.9 ± 6.4 17.0 ± 7.9
Homocysteine (μmol/l) 9.8 ± 3.1 9.6 ± 2.8 9.8 ± 2.9
Fibrinogen (mg/dl) 379 ± 42 384 ± 46 380 ± 48
Systolic blood pressure (mmHg) 131.4 ± 4.2 131.6 ± 4.0 131.0 ± 3.7
Diastolic blood pressure (mmHg) 84.6 ± 4.4 85.2 ± 3.6 84.5 ± 3.9
Daily energy intake (MJ) 4.9 ± 0.5 5.1 ± 0.4 5.0 ± 0.5
Carbohydrate (% of energy) 46.8 ± 1.7 46.2 ± 1.9 46.4 ± 1.9
Protein (% of energy) 20.2 ± 1.4 20.9 ± 1.7 21.0 ± 1.6
Total fat (% of energy) 33.0 ± 1.8 32.9 ± 1.5 32.6 ± 1.5
Saturated fat (% of fat) 29.1 ± 1.3 28.7 ± 1.6 28.5 ± 1.8
Polyunsaturated/saturated fats 0.6 ± 0.07 0.6 ± 0.09 0.6 ± 0.09
Cholesterol (mg) 265.4 ± 36.4 261.4 ± 30.1 263.8 ± 26.9
Total fibre (g) 14.6 ± 2.5 15.4 ± 1.9 14.8 ± 2.0
Soluble fibre (g) 3.9 ± 0.4 4.1 ± 0.8 3.8 ± 0.8

aminophenylboronic acid affinity chromatography (DIA-
MAT, Bio-Rad, USA; normal values 4.2–6.2%), with
intra- and interassay coefficients of variation of <2%
[23]. The estimate of insulin resistance was calculated by
homeostasis model assessment index (HOMA-IR) using
the formula:
HOMA-IR = FPI (μU/ml)↔FPG (mmol/l)/22.5
as described by Matthews et al. [24].
Fibrinogen was measured in tripotassium
EDTA–plasma with a standardised immunonephelomet-
ric method (BNA Behring). The CV was 3.3%.
Homocysteine was measured by a modified procedure
of Araki and Sako [25] with high-pressure liquid chro-
matography and fluorescence detection. The intra-assay
variation of the method was 2.5%.
Statistics
An intention-to-treat analysis was conducted in patients
who had received at least one dose of study medication
and had a subsequent efficacy observation. Patients were
included in the safety analysis if they had received one
dose of trial medication after randomisation and had a
subsequent safety observation. The null hypothesis that
the change in mean studied parameters from baseline to
the end of 6 months of treatment did not differ signifi-
cantly among psyllium, guar and dietary treatments was
tested using analysis of variance (ANOVA) and analysis
of covariance (ANCOVA) models. The statistical signifi-
cance of the independent effects of treatment on the other
parameters was determined by ANCOVA. A one-sample
t-test was used to compare values obtained before and
after treatment administration, and two-sample t-tests
were used for between-group comparison. Then we car-
ried out a multivariate analysis to evaluate if the observed
changes in some variables (especially the insulin-resist-
ance related ones) is simply related to the body weight
change or to a specific dietary intervention. Statistical
analysis of data was performed by means of the SPSS
statistical software package for Window (version 11.0;
Chicago, IL); data are presented as mean ± SD. For all
statistical analysis, a pvalue less than 0.01 was consid-
ered statistically significant [26].
Results
For the duration of the study, no significant change in
dietary habit or physical activity was observed. Adherence
to the AHA Step 2 diet was considered similar for all
groups, especially regarding energy consumption. The
main results of the study are summarised in Tables 2–4.
Metabolic effects
Long-term treatment of both tested fibres is associated
with a significant improvement in both glycaemic and
plasma lipid control in the studied subjects. After 4 and
6 months of psyllium supplementation, from baseline
values we observed a mean decrease in FPG of 1 mmol/l
(t = 3.01, p < 0.001) and 1.33 mmol/l (t = 6.59, p <
0.001), in FPI of 3.1 μU/ml (t = 2.81, p = 0.005) and 5.1
μU/ml (t = 4.90, p < 0.001), in HOMA Index of 2.1 (t =
4.47, p < 0.001) and 2.9 (t = 6.55, p < 0.001), in HbA1c
of 0.4% (t = 3.01, p < 0.001) and 0.7% (t = 5.71, p <
0.001), in TC of 0.18 mmol/l (n.s.) and 0.31 mmol/l (t =
2.72, p = 0.008), in LDL-C of 0.13 mmol/l (t = 3.92, p <
0.001) and 0.23 mmol/l (t = 5.69, p < 0.001), in Apo B
of 5 mg/dl (n.s.) and 11 mg/dl (t = 2.68, p = 0.009) and
in TG of 0.13 mmol/l (n.s.) and 0.24 mmol/l (t = 5.35, p
< 0.001).
After 4 and 6 months of guar supplementation, we
observed a mean decrease in FPG of 0.55 mmol/l (t = 2.69,
p = 0.009) and 0.66 mmol/l (t = 2.71, p = 0.009), in FPI of
0.8 μU/ml (n.s.) and 2.7 μU/ml (t = 2.74, p = 0.008), in
HOMA Index of 0.8 (n.s.) and 1.2 (t = 2.77, p = 0.008), in
HbA1c of 0.3% (n.s.) and 0.7% (t = 4.90, p<0.001), in TC
of 0.25 mmol/l (n.s.) and 0.31 mmol/l (t = 2.79, p = 0.008),
in LDL-C of 0.13 mmol/l (t = 3.11, p = 0.006) and 0.26
mmol/l (t = 4.09, p = 0.002) and in Apo B of 2 mg/dl (n.s.)
and 6 mg/dl (t = 2.71, p = 0.009), while no change was
noted regarding TG plasma concentration.
Neither the psyllium-treated group nor the guar-treat-
ed group experienced any significant change in plasma
HDL-C, Lp(a) or basal homocysteine.
The step 2 AHA diet determined a stabilisation of the
studied metabolic parameters without any significant dif-
ference in comparison to the baseline.
Effects on blood pressure
Long-term supplementation with psyllium is associated
with a significant decrease of SBP after both 4 months and
6 months of treatment: –3.1 (–3.3) mmHg (t = 4.08, p <
0.001) and –5.2 mmHg (t = 6.51, p < 0.001), respectively.
A significant mean 2.2 mmHg decrease in DBP was
also observed after 6 months of supplementation (t =
6.51, p < 0.001).
Guar supplementation is associated with a speedier
improvement in SBP at 4 months (–5.3 mmHg, t = 6.34,
p < 0.001), but this was not confirmed in the ensuing
study visits. No significant effect has been observed as
regards DBP.
The AHA Step 2 diet did not determine a significant
change in blood pressure in comparison to the baseline.
50 Mediterr J Nutr Metab (2010) 3:47–54

Waist circumference (WC)
Long-term treatment with both tested fibres is associated
with a significant improvement in the studied subjects.
In the psyllium-treated patients the WC decrease was
statistically significant after 4 months of supplementa-
tion (–3.9 cm, t = 2.11, p = 0.037) and continued after 6
months (–4.1 cm, t = 8.94, p < 0.001).
In the guar-treated patients the WC decrease was even
statistically significant after the first 4 months of supple-
mentation (–4.60, t = 2.59, p = 0.011); it progressively
continued and was then maintained till 6 months (–5.2, t
= 2.95, p < 0.004).
Combining these facts, at the end of the study we
observed that 12.5% of patients (6 subjects) in the psyl-
lium group did not comply with the criteria for the diag-
nosis of MS against the 2.1% of patients in the guar
group (1 subject). The prevalence of MS in the control
group was not changed by the AHA Step 2 diet.
Tolerability
No patient withdrew from the study because of serious
adverse events. Three patients in the psyllium group and
four in the guar group experienced transient intercurrent
51
Mediterr J Nutr Metab (2010) 3:47–54
Table 2 Modification of studied parameters during psyllium husk supplementation
Baseline 2 Months 4 Months 6 Months
Body weight (kg) 80.2 ± 4.1 79.1 ± 3.9a,ba, 78.3 ± 3.6a,ba, 76.9 ± 4.1a,b,c
Waist circumference (cm) 100.4 ± 10.3 96.5 ± 7.6a,ba, 96.4 ± 7.4a,ba, 96.3 ± 7.2a,ba,
Glycated haemoglobin (%) 6.7 ± 0.6 6.3 ± 0.7a,b,c 6.2 ± 0.6a,ba, 6.0 ± 0.6a,ba,
Fasting plasma glucose (mmol/l) 6.1 ± 1.2 5.1 ± 1a,b,c 4.9 ± 0.9a,b,c 4.8 ± 0.8a,b,c
Fasting plasma insulin (μU/ml) 25.2 ± 5.1 22.1 ± 5.4a,ba, 21.2 ± 5.3a,ba, 20.1 ± 5.1a,b,c
HOMA Index 7.4 ± 2.9 5.3 ± 1.8a,b,c 4.9 ± 1.4a,b,c 4.5 ± 1.0a,b,c
Total cholesterol (mmol/l) 4.8 ± 0.6 4.6 ± 0.6a,b,c 4.5 ± 0.5a,ba, 4.5 ± 0.5a,ba,
LDL-cholesterol (mmol/l) 2.9 ± 0.3 2.8 ± 0.3a,ba, 2.8 ± 0.3a,ba, 2.7 ± 0.3a,ba,
HDL-cholesterol (mmol/l) 1.10 ± 0.13 1.11 ± 0.13a,b,c 1.06 ± 0.13a,b,c 1.11 ± 0.1a,b,c
Triacylglycerols (mmol/l) 1.8 ± 0.3 1.7 ± 0.3a,b,c 1.6 ± 0.2a,ba, 1.6 ± 0.2a,ba,
Apolipoprotein A-I (mg/dl) 130 ± 18 126 ± 16a,b,c 128 ± 18a,b,c 131 ± 19a,b,c
Apolipoprotein B (mg/dl) 105 ± 22 100 ± 23a,b,c 97 ± 19a,b,c 94 ± 18a,b,c
Lipoprotein (a) (mg/dl) 17.1 ± 7.7 15.3 ± 5.7a,b,c 14.6 ± 4.8a,b,c 15.4 ± 5.9a,b,c
Homocysteine (μmol/l) 9.8 ± 3.1 10.6 ± 2.6a,b,c 10.1 ± 2.6a,b,c 9.9 ± 2.8a,b,c
Fibrinogen (mg/dl) 379 ± 42 362 ± 40aa,a, 365 ± 39a,b,c 361 ± 38b,c
Systolic blood pressure (mmHg) 131.4 ± 4.2 128.1 ± 3.7a,ba, 127.8 ± 3.7a,ba, 126.2 ± 3.6a,ba,
Diastolic blood pressure (mmHg) 84.6 ± 4.4 83.2 ± 3.3a,b,c 85.4 ± 3.6a,b,c 82.4 ± 3.0a,ba,
ap < 0.01 in comparison to baseline (ANOVA test); bp < 0.01 in comparison to AHA Step 2 diet group (ANCOVA test); cp < 0.01 in comparison
to the guar group (ANCOVA test)
Table 3 Modification of studied parameters during partially hydrolysed guar gum supplementation
Baseline 2 Months 4 Months 6 Months
Body weight (kg) 79.9 ± 4.5 77.5 ± 3.9a,b,c 77.9 ± 4.3a,b 78.3 ± 4.4a,b
Waist circumference (cm) 101.7 ± 9.5 96.4 ± 7.3a,ba, 96.3 ± 7.4a,b 96.5 ± 7.7a,b
Glycated haemoglobin (%) 6.8 ± 0.7 6.5 ± 0.8a,b,c 6.2 ± 0.7a,b 6.1 ± 0.7a,b
Fasting plasma glucose (mmol/l) 6.0 ± 1.3 5.4 ± 0.7a,ba, 5.4 ± 0.7a,b 5.33 ± 0.8a,b
Fasting plasma insulin (μU/ml) 24.9 ± 5.8 24.1 ± 4.0a,b,c 22.5 ± 2.2a,b 22.2 ± 2.8a,ba,
HOMA Index 7.2 ± 2.5 6.4 ± 2.2a,b,c 6.1 ± 1.9a,b 6.0 ± 1.8ba,
Total cholesterol (mmol/l) 4.9 ± 0.6 4.7 ± 0.6a,b,c 4.6 ± 0.7a,b 4.6 ± 0.7ba,
LDL-cholesterol (mmol/l) 3.0 ± 0.4 2.9 ± 0.4a,ba, 2.7 ± 0.4a,b 2.7 ± 0.3a,b
HDL-cholesterol (mmol/l) 1.2 ± 0.1 1.06 ± 0.13a,b,c 1.11 ± 0.1a,b 1.13 ± 0.07a,b
Triacylglycerols (mmol/l) 1.7 ± 0.2 1.6 ± 0.2a,b,c 1.6 ± 0.2a,b 1.6 ± 0.3a,b
Apolipoprotein A-I (mg/dl) 129 ± 16 127 ± 15a,b,c 129 ± 170a,b 127 ± 16a,b
Apolipoprotein B (mg/dl) 107 ± 25 105 ± 21a,b,c 102 ± 24a,b 101 ± 26a,ba,
Lipoprotein (a) (mg/dl) 15.9 ± 6.4 146 ± 59a,b,c 139 ± 49a,b 144 ± 49a,b
Homocysteine (μmol/l) 9.6 ± 2.8 9.0 ± 2.4a,b,c 9.6 ± 3.0a,b 9.1 ± 2.6a,b
Fibrinogen (mg/dl) 384 ± 46 3770 ± 400a,b,c 3710 ± 390a,b 373 ± 400a,b
Systolic blood pressure (mmHg) 131.6 ± 4.0 127.7 ± 4.0aa,a, 129.1 ± 3.9aa, 128.2 ± 3.7aa,
Diastolic blood pressure (mmHg) 85.2 ± 3.6 84.1 ± 3.7a,b,c 83.6 ± 3.6a,b 83.4 ± 3.5a,b
ap < 0.01 in comparison to baseline (ANOVA test); bp < 0.01 in comparison to AHA Step 2 diet group (ANCOVA test); cp < 0.01 in comparison
to the psyllium group (ANCOVA test)

abdominal bloating and one patient in the psyllium group
and three of the guar group withdrew after 3 months of
treatment for this reason. One patient in the psyllium
group and three patients in the guar group also experi-
enced intercurrent diarrhoea, but no one withdrew from
the study for this reason.
Discussion
Prevention of disease rather than its alleviation or cure
has always been the aim of healthcare professionals.
While this goal has been achieved for many infectious
diseases through improvements in hygiene and vaccina-
tion, as well as acute deficiency diseases such as scurvy,
less progress has been made with chronic diseases like
atherosclerosis-related diseases [27]. The clustering of
several metabolic and cardiovascular disease risk factors
has been termed the MS. The MS seems to result from a
collision between susceptible “thrifty genes” and a soci-
ety characterised by an increased prevalence of obesity
and a sedentary lifestyle [28]. The typical patient is char-
acterised by abdominal obesity, a varying degree of glu-
cose intolerance, dyslipidaemia and/or hypertension. The
components of the MS are associated with insulin resist-
ance, disturbances of coagulation and fibrinolysis,
endothelial dysfunction and elevated markers of sub-clin-
ical inflammation [29].
As suggested by the NCEP ATP III [15], the first ther-
apeutic approach to the MS should be improvement of
lifestyle and diet. Among dietary suggestions, the need to
increase fibre intake with nutrients or supplements is
highlighted [30]. Among supplemented fibres, those that
appear to have the best metabolic effect are the soluble
ones: psyllium, guar, pectin and oats [31]. Dietary fibre
may also be related inversely to blood pressure and
dietary supplementation, which seems to have a slight
blood pressure-lowering effect [32–34].
While oats are a food per se and pectins are widely
available in different fruits, psyllium and guar have to be
taken as dietary supplements. So, we decided to test the
long-term effect of dietary supplementation of psyllium
or guar, the most widely available isolated soluble fibres
on the Italian market, on the clinical features of the MS.
Our results show that a long-term supplementation
with moderately high dosages of soluble fibre is able to
improve most parameters related to the MS. In fact, com-
paring the effects of psyllium and guar supplementation
of patients affected by MS we observed that both kinds of
fibre are able to significantly improve BMI (–2.9% and
–3.3%, respectively), FPG (–16.4% and –9.3%, respec-
tively) and LDL-C (–4.4% and –4.3%, respectively) after
4 months of treatment, and a larger range of metabolic
parameters after 6 months: BMI (–7.2% and –6.5%,
respectively), FPG (–27.9% and –11.1%, respectively),
FPI (–20.4% and –10.8%, respectively), HOMA Index
(–39.2% and –16.7%, respectively), HbA1c (–10.4% and
–10.3%, respectively), TC (–7.5% and –6.3%, respective-
ly), LDL-C (–7.9% and –8.5%, respectively) and Apo B
(–10.5% and –5.6%, respectively). Apart from the speed
and efficacy, only the 6-month psyllium supplementation
exerted a significant improvement on plasma TG concen-
tration (–13.3%) and on SBP (–3.9%) and DBP (–2.6%),
the two main components of the MS. These data are rel-
evant and justify why at the end of the study 12.5% of
patients in the psyllium group did not comply with the
52 Mediterr J Nutr Metab (2010) 3:47–54
Table 4 Modification of studied parameters during AHA Step 2 diet
Baseline 2 Months 4 Months 6 Months
Body weight (kg) 80.1 ± 4.3 79.4 ± 4.2a,b,c 78.7 ± 4.6a,c,c 78.9 ± 4.3a,c
Waist circumference (cm) 102.0 ± 8.3 96.4 ± 6.4a,b,c 96.9 ± 7.1a,b,c 99.5 ± 7.3b,c
Glycated haemoglobin (%) 6.6 ± 0.9 6.5 ± 0.9b,b,c 6.5 ± 0.4b,c,c 6.6 ± 0.7b,c
Fasting plasma glucose (mmol/l) 6.1 ± 1.3 5.5 ± 0.8a,b,c 5.7 ± 0.9b,c,c 5.9 ± 0.8b,c
Fasting plasma insulin (μU/ml) 25.0 ± 5.5 24.3 ± 4.2b,b,c 23.8 ± 2.9b,c,c 24.2 ± 3.8b,c
HOMA Index 7.2 ± 2.8 6.6 ± 2.1b,b,c 6.5 ± 2.4b,c,c 6.6 ± 1.9b,c
Total cholesterol (mmol/l) 4.8 ± 0.7 4.5 ± 0.6a,b,c 4.6 ± 0.9b,c,c 5.0 ± 0.7b,c
LDL-cholesterol (mmol/l) 3.0 ± 0.3 2.9 ± 0.5b,c,c 2.9 ± 0.7b,c,c 2.9 ± 0.5b,c
HDL-cholesterol (mmol/l) 1.1 ± 0.1 1.12 ± 0.11a,b,c 1.11 ± 0.14,c,c,c 1.12 ± 0.15a,b,c
Triacylglycerols (mmol/l) 1.7 ± 0.3 1.5 ± 0.3a,b,c 1.5 ± 0.6a,b,c 1.6 ± 0.4b,c
Apolipoprotein A-I (mg/dl) 129 ± 14 132 ± 16a,b,c 131 ± 17,c,c,c 128 ± 14,c,c
Apolipoprotein B (mg/dl) 106 ± 20 101 ± 19a,b,c 101 ± 23b,c,c 105 ± 22b,c
Lipoprotein (a) (mg/dl) 17 ± 7 17 ± 6a,b,c 18 ± 5a,b,c 16 ± 6a,b,c
Homocysteine (μmol/l) 9.8 ± 2.9 9.4 ± 1.4a,b,c 9.7 ± 2.8a,b,c 9.6 ± 2.9a,b,c
Fibrinogen (mg/dl) 380 ± 48 371 ± 29a,b,c 369 ± 31a,b,c 374 ± 42a,b,c
Systolic blood pressure (mmHg) 131.0 ± 3.7 129.2 ± 4.1b,c,c 129.3 ± 4.2b,c,c 130.0 ± 3.9b,c
Diastolic blood pressure (mmHg) 84.5 ± 3.9 83.9 ± 3.8a,b,c 83.5 ± 3.7a,b,c 83.8 ± 4.0b,c
ap < 0.01 in comparison to baseline (ANOVA test); bp < 0.01 in comparison to the psyllium group (ANCOVA test); cp < 0.01 in comparison to
the guar group (ANCOVA test)

criteria for the diagnosis of the MS compared with only
the 2.1% in the guar group.
No statistically significant association was found
between body weight loss in the whole patient sample or
in the subsamples, probably because of the relatively
small patient sample and the relatively high standard
deviation of body weight change.
Previously randomised clinical trials and meta-analy-
ses demonstrated the efficacy of soluble fibres, and in
particular of psyllium and guar gum, as antihypercholes-
terolaemic agents in moderately hypercholesterolaemic
subjects and as a glycaemic improver in diabetic subjects
[9, 35]. Our studies confirm the previously observed
effect highlighting the possibility that long-term treat-
ment with highly dosed soluble fibres could significantly
improve parameters related to insulin resistance, the
pathogenetic basis of the MS and type 2 diabetes [36].
This effect appears to be much more relevant with psylli-
um supplementation than with guar gum.
Data on the effects of both psyllium and guar gum on
body weight management are promising, but as yet not
sufficient to recommend the current use of soluble fibres
as a therapeutic agent in this field. The main reasons are
the relative brevity of the studies carried out to date and
the relatively low dosage tested [37]: in our study, car-
ried out with high daily dosage of fibres for one year,
both soluble fibres contributed significantly to the body
weight decrease observed in the patients, even though
the dosages differed. This effect could be one of the
main ones responsible for the observed long-term
improvement in metabolic parameters during fibre sup-
plementation.
Overall, entering the pre- and post-treatment data into
software specifically created to estimate the 5-year risk
for a major cardiovascular event in the Italian population
[38], we observed that the baseline relative risk for each
subject/5 years for 1000 patients treated with psyllium
decreased from 0.78 ± 0.09 to 0.68 ± 0.08, without sig-
nificant differences between the sexes. The relative risk
for patients treated with guar decreased from 0.77 ± 0.08
to 0.67 ± 0.10, without significant differences between
the sexes. Although relatively small in terms of patient
treatment, the observed reduction in cardiovascular dis-
ease risk is likely to be significant on a population basis.
The main limitation of our study is the lack of a dou-
ble-blind design (very hard because of the different
organoleptic characteristics of the two fibres). However,
to the best of our knowledge, this is the first clinical trial
that directly compares the long-term metabolic effect of
a high daily supplementation of soluble fibres for
patients affected by the MS and the trial design was
strengthened by a third control group only treated with a
non-supplemented diet.
Because of the relatively small sample of selected
patients in this study, the results should be extrapolated
cautiously, even though other studies have previously
confirmed the good long-term tolerability of this kind of
treatment [39, 40].
Therefore, the observed results show how fibre sup-
plementation, when recommended, has to be person-
alised on the basis of the specific prevalent metabolic
problem of each patient. In conclusion, our results show
that both fibres could have a positive effect in the man-
agement of the patient affected by multiple cardiometa-
bolic risk factors. However, psyllium could be more
strongly indicated for patients that have to reduce a large
number of cardiovascular risk factors such as hypercho-
lesterolaemia, hypertriglyceridaemia, hyperglycaemia
and hypertension, while guar gum use is associated to a
more rapid body loss effect, which could support patient
compliance to the suggested diet (even though after 4
months the body weight loss associated to either psylli-
um and guar intake become similar).
Abbreviations
SBP Systolic blood pressure
DBP Diastolic blood pressure
TC Total cholesterol
LDL-C Low-density lipoprotein cholesterol
HDL-C High-density lipoprotein cholesterol
TG Triglycerides (triacylglycerols)
ApoAI Apolipoprotein AI
ApoB Apolipoprotein B
Lp(a) Lipoprotein (a)
FPG Fasting plasma glucose
FPI Fasting plasma insulin
HOMA Index homeostasis assessment index
HbA1c Glycated haemoglobin
FBG Fibrinogenaemia
Hcys Basal homocysteinaemia
Conflict of interest The authors declare that they have no conflict of
interest related to the publication of this manuscript.
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