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32 ALTERNATIVE THERAPIES, jul/aug 2007, VOL. 13, NO. 4
A Fractionated White Bean Extract for Weight Loss
Jay Udani, MD, is an assistant clinical professor at the
University of California, Los Angeles School of Medicine,
Medical Director of the Integrative Medicine Program at
Northridge Hospital, and an adjunct professor in the research
division of Southern California University of Health Sciences.
Betsy B. Singh, PhD, is president, BRCG, Midlothian, Va.
A
s weight gain and obesity have become central in
the minds of the public and health professionals
alike, a dizzying array of nutritional supplement
options for weight loss have become available. The
vast majority of the products are either untested,
useless, or, in some cases, unsafe.
1
One popular method of nutritional dieting is the low-carbo-
hydrate diet, which has become mainstream through the efforts
of Atkins and others. The ability to reduce effective carbohydrate
intake through the inhibition of amylase has been researched for
over 20 years, starting with unpurifi ed white kidney bean prod-
ucts in the 1980s
2-5
and more recently with purified water
extracts. The central theory is that the digestion of carbohydrates
begins with salivary amylase in the mouth and continues with
pancreatic amylase in the gut. The ability to block these enzymes
may result in a decrease in the digestion of complex carbohy-
drates into mono- and disaccharides, which are then absorbed
by the gut and stored in skeletal tissue and in the liver as glyco-
gen or stored in adipose tissue after conversion to triglycerides
and fatty acids.
6
The white bean extract is a water extract of a common white
bean (Phaseolus vulgaris). Phaseolus vulgaris has been shown in
vitro to inhibit the digestive enzyme alpha-amylase.
2,7-9
This
white bean extract has undergone acute and chronic (90-day)
animal toxicity studies, which have not demonstrated any clini-
cal or pathological toxicity associated with ingestion of white
bean extract.
10
Prior to this study, human clinical trials were conducted on
the starch-neutralizer bean extract product. Four studies have
been conducted. Two of these studies generated internal compa-
ny data that remain unpublished,
11,12
though the internal reports
indicated that between-group differences were found. Two other
studies have been conducted. One study (the only published
study to date) showed a trend toward weight reduction but did
not reach statistical signifi cance,
13
and one study did not show
any difference between the placebo and active group.
14
The cited studies tested the white bean extract as a single
BLOCKING CARBOHYDRATE ABSORPTION AND
WEIGHT LOSS: A CLINICAL TRIAL USING A
PROPRIETARY FRACTIONATED WHITE BEAN EXTRACT
Jay Udani, MD; Betsy B. Singh, PhD
original research
Background • A proprietary fractionated white bean extract of
Phaseolus vulgaris has been shown in vitro to inhibit the digestive
enzyme alpha-amylase. This may prevent or delay the digestion
of complex carbohydrates, potentially resulting in weight loss.
Methods • A 4-week randomized, double-blind, placebo-
controlled study of 25 healthy subjects consuming 1000 mg of a
proprietary fractioned white bean extract or an identical placebo
twice a day before meals in conjunction with a multi-component
weight-loss program, including diet, exercise, and behavioral
intervention, was conducted.
Results • Both groups reduced their weight and waist size sig-
nifi cantly from baseline. The active group lost 6.0 lbs (P=.0002)
and 2.2 in (P=.0050), and the placebo group lost 4.7 lbs
(P=.0016) and 2.1 in (P=.0001). The differences between groups
were not signifi cant (weight P=.4235, waist size P=.8654).
Through subsequent exploratory analysis to investigate group
fi ndings further, subjects were stratifi ed by total dietary carbo-
hydrate intake. This probative analysis revealed that the tertile
of subjects who had consumed the most carbohydrates demon-
strated signifi cant reductions in both weight (8.7 lbs vs 1.7 lbs,
P=.0412) and waist size (3.3 in vs 1.3 in P=.0100) compared with
placebo subjects in the same tertile of carbohydrate intake.
Conclusion • Subjects who adhere to a program including
dietary modifi cation, exercise, and behavioral intervention can
signifi cantly reduce their weight and waist size in a short period
of time. In an exploratory analysis of data, the tertile of subjects
who ate the most carbohydrates experienced a signifi cant
reduction in both weight and waist size with the addition of the
white bean extract compared to the placebo group of the same
tertile of carbohydrate consumption. Longer studies with a
larger pool of subjects are required to validate these fi ndings.
(Altern Ther Health Med. 2007;13(4):32-37.)
A Fractionated White Bean Extract for Weight Loss
ALTERNATIVE THERAPIES, jul/aug 2007, VOL. 13, NO. 4 33
component in a weight loss trial. This pilot study was conducted
to determine whether the extract would be a useful component
in a short-term, multifaceted weight loss program including diet,
exercise, and behavior modifi cation.
METHODS
This study was conducted in accordance with good clinical
practices, which encompass the International Conference on
Harmonisation and Helsinki Declaration. A randomized, double-
blind, placebo-controlled trial was performed to determine if the
addition of 1000 mg of the white bean extract twice a day to a
multi-component weight loss program would demonstrate a sig-
nifi cant difference in weight loss, waist size, hip size, triglycer-
ides, fasting glucose, total cholesterol, appetite control, hunger,
energy level, and percentage of body fat. The study sample was
25. It is acknowledged that the sample size was less than that
required by a power calculation based on earlier data. However,
funding from the sponsor could support only a small sample size
in this pilot study due to the multi-factorial nature of the study.
Sample Generation
Participants were identified through mass community
recruitment. The inclusion criteria for the study were as follows:
(1) age >18 and <40 at screening; (2) body mass index (BMI) ≥23
kg/m
2
and ≤31 kg/m
2
at screening; (3) agreement to maintain
diet, exercise, and behavioral modifi cation guidelines while par-
ticipating in the study; (4) agreement to periodic follow-up; and
(5) females’ agreement to use appropriate birth control methods
during the active study. Exclusion criteria included the following:
(1) use of any drugs, herbs, or other non-prescription prepara-
tions for obesity within 4 weeks of screening, including but not
limited to sibutramine, orlistat, Fen-phen (Wyeth, Madison, NJ),
Metabolife products (Ideasphere Inc, American Fork, Utah),
diuretics, etc; (2) abnormal electrocardiogram (EKG), complete
blood count (CBC), metabolic panel, or physical examination;
(3) an active eating disorder; (4) severe hepatic or renal disease;
(5) history of seizures, alcohol abuse, chronic malabsorption,
diverticulosis, or diverticulitis; (6) diagnosis of coronary artery
disease, congestive heart failure, stroke, arrhythmia, or uncon-
trolled hypertension; (7) pregnancy or lactation; (8) inability to
understand or follow the study protocol; (9) diagnosis of signifi -
cant psychiatric disease or depression; and (10) known sensitivi-
ties to the product.
Screening
Prior to participating in any study-related procedures, includ-
ing clinical screen, potential subjects read and signed a Southern
California University of Health Sciences Institutional Review Board–
approved consent form. A clinical screening followed, including an
EKG, blood work (comprehensive metabolic panel, which included
serum electrolytes, liver, and kidney function tests, lipid panel, and
CBC including differential), and physical by a medical doctor.
Subjects fasted from midnight the night prior to a blood draw until
they had attended morning lab. A cardiologist read the EKG results
to rule out any abnormalities prior to study participation, as the
study required an exercise component. The participants also met
individually with a registered dietician, a certifi ed physical trainer,
and a behavioral psychologist before the initiation of the study to
determine if there were any reasons that compliance with the vari-
ous aspects of the study would not be possible.
Study Interventions
After this screening period, participants were randomly
allocated to receive either the proprietary fractionated white
bean extract or identical placebo in a double-blind manner.
Assessors and participants were blinded to group assignment.
Two people dropped out after having been randomized. One
withdrew from the study before receiving any product, and
another withdrew after receiving product but without ingesting
it or following other protocol requirements. These people are not
included in the data analysis.
The white bean extract was administered in the form of a
500-mg capsule. The product is a water extract of the white kid-
ney bean Phaseolus vulgaris. Non−genetically modifi ed organism
(GMO) whole white kidney beans were ground and then extract-
ed for 4 hours. The liquid was fi ltered and concentrated under
vacuum. The extract was filtered again and then pasteurized
before being spray dried. The product was in capsule form and
was supplied by Pharmachem Labs, Kearny, NJ.
A capsule of identical appearance, texture, taste, and smell
was used as the placebo. Participants were advised to take 2 cap-
sules (1000 mg) at the beginning of breakfast and lunch each day.
No other drugs, herbs, or non-prescription products for obesity
were allowed during the study.
An intensive dietary intervention included weekly personal
meetings with a registered dietician, during which instructions
were reiterated and prepared food was provided for the 2 meals
per day when the extract or placebo was taken. Participants in
the study were monitored throughout the trial by use of a daily
diet record, which was evaluated by a registered dietician to
determine whether participants consumed carbohydrates within
the range indicated in the protocol. Other dietary factors such as
fats, protein, fiber, and so forth, were monitored as well.
Participants in both groups were supplied with supplemental
foods that met the diet parameters to facilitate compliance and
avoided diet restrictions that could produce a fi nancial burden
for participants. Breakfast and lunch were provided on a daily
basis, and dinners were prepared along dietary guidelines by
participants. Participants were instructed to maintain a daily
caloric intake of 1800 calories. Additionally, they received an
exercise regimen that instructed them to exercise for at least 30
minutes 4 times a week.
Exercise periods were supervised by a personal trainer to
monitor activity to produce equivalency in effort among subjects
for this component. Subjects were assessed on their baseline visit
by the trainer and during weeks 2, 3, and 4 of the study were mon-
itored to make sure that effort was stable despite the possibility of
habituation to the initial routine. This trial supervision was includ-
34 ALTERNATIVE THERAPIES, jul/aug 2007, VOL. 13, NO. 4
A Fractionated White Bean Extract for Weight Loss
ed to eliminate as much bias as possible in the exercise component
between groups and intra-individually over time in the trial.
Finally, subjects participated in weekly group behavioral
therapy sessions led by a licensed psychologist to address per-
sonal eating issues that potentially may have led to noncompli-
ance to the protocol.
Outcome Measures and Data Collection
The primary outcome measure was weight loss. The second-
ary outcome measures included body composition (determined
by bioelectrical impedance); waist and hip measurements; glu-
cose, triglyceride and cholesterol levels; and subjective assess-
ment of hunger, energy, and appetite via the 10-point visual
analog scale. Adherence to the study-recommended personalized
diet was monitored with the help of a daily diet diary and weekly
review with feedback from a registered dietician. All data were
collected at baseline and at the end of weeks 1, 2, 3, and 4. A sec-
ond blood test was obtained at the end of the study to confi rm
product safety. A closing interview was conducted to determine
compliance on all components of protocol and to make a fi nal
determination of presence or absence of side effects. Compliance
was additionally audited using pill counts and records of both
exercise and diet support group attendance.
Bioassays
Standard metabolic spectro-photometric assays were run on
a Cell Dyn 4000 machine (Abbott Laboratories, Abbott Park, Ill)
for complete blood counts (including white blood cells, hemoglo-
bin, hematocrit, and platelets), and comprehensive metabolic
panels (including liver and kidney function tests) were run on an
AU-5200 (Olympus Japan Co Ltd, Tokyo).
Apparati
The Tanita Body Composition Analyzer (Tanita Corporation
of America, Inc, Arlington Heights, Ill) bioelectrical impedance
machine was used to obtain body composition.
The Office Medic Electrocardiograph, version 4.23 (QRS
Diagnostic, LLC, Plymouth, Minn), was used to obtain EKGs.
DESIGN AND PROCEDURES
A randomized, double-blind, placebo-controlled study was
conducted for 4 weeks. Subjects participated in 5 visits over the
course of 5 weeks; 1 baseline (week 0) and 4 clinical visits (weeks
1, 2, 3, and 4). Each subject provided written informed consent
before entry into the trial.
Baseline Visit
The initial screening visit included a medical history, physi-
cal examination, body weight evaluation, and clinical chemistry
and hematology laboratory tests.
Upon eligibility, subjects were randomized and given their
medication instructions along with diet instruction from a regis-
tered dietician. The following clinical visit was scheduled 1 week
from baseline.
Clinical Visits
End of Week 1 (Visit 2)
During the second visit, participants had their weight mea-
sured, and bioelectrical impedance was performed for body fat
composition. Also, 10-point subjective scales for hunger, appetite
control, and energy were completed.
End of Week 2 (Visit 3) to End of Week 4 (Visit 5)
From week 2 to week 4, participants had their weight mea-
sured, and bioelectrical impedance was performed for body fat
composition. During each visit, 10-point subjective scales for
hunger, appetite control, and energy were completed. On the last
visit, an additional blood draw was executed to repeat clinical
chemistry and hematology laboratory tests taken at baseline.
Statistical Analysis
Before conducting the statistical analysis, all appropriate
tests were conducted and assumptions for parametric tests were
met for all outcome measures. As such, for within-group analy-
sis, 2-sided paired t-tests evaluating changes from baseline were
conducted. For between-group analyses, independent t-test and
analysis of variance was conducted.
Additional exploratory analysis was performed by stratify-
ing subjects into tertiles (Low/Medium/High) based on body
mass index, total carbohydrate intake, and net carbohydrate
intake (total carbohydrate intake minus dietary fi ber intake). All
7 effi cacy parameters were analyzed separately for each stratum.
Sociodemographic Characteristics and Baseline Health
Parameters
Table 1 describes the socio-demographic characteristics of the
study sample: 54% of the active group was male vs 83% for the pla-
cebo group. The racial, marital, and educational distributions are
also presented in Table 1. Due to sparse data, no statistical tests
were used for the socio-demographic data. Table 1 also represents
baseline data for glucose and total cholesterol levels and indepen-
dent t-tests were conducted to examine group differences. The
results indicate no statistically signifi cant difference between the
active and placebo groups for glucose and total cholesterol levels.
Of the 25 subjects who participated in the study, 13 partici-
pants were in the active group and 12 in the placebo group. The
mean weight for the active group was 178.29 lbs and 178.35 lbs
in the placebo group. Mean BMI was 26.93 kg/m
2
in the active
group and 26.07 kg/m
2
in the placebo group (Table 2).
RESULTS
All blood work measurements were compared at baseline
and end of study, and no significant differences were found
between the 2 groups (Tables 3 and 4). For each week, average
calories, carbohydrates, protein, fat, and fi ber intake were com-
puted and compared between the 2 groups. No signifi cant differ-
ences were found except for fat intake in week 3. The active
group had a higher fat intake—18.7 vs 17.1—than the placebo
group (data not shown).
A Fractionated White Bean Extract for Weight Loss
ALTERNATIVE THERAPIES, jul/aug 2007, VOL. 13, NO. 4 35
Weight
The active group lost 6 lbs (3.4%) in 4 weeks, and the place-
bo group lost 4.7 lbs (2.6%) in the same time period (Table 5).
The change from baseline was statistically significant in each
group (active P=.0002, placebo P=.0016); however, the between-
group analysis was not statistically signifi cant (P=.4235).
When the groups were stratified by total carbohydrate
intake, those in the highest tertile demonstrated a signifi cant dif-
ference between groups. The active group lost 8.7 lbs, and the
placebo group lost 1.7 lbs with a between-group difference of
P=.0412. There were no signifi cant differences seen in the low or
medium tertiles for total carbohydrate intake nor were there any
signifi cant differences seen in the stratifi cation of the BMI or net
carbohydrate intake groups.
Waist Size
In 4 weeks, the active group lost 2.2 in from their waists
(P=.050 compared with baseline) and the placebo group lost 2.1 in
from their waists (P=.0001 compared with baseline, Table 6). The
between-group analysis was not statistically signifi cant (P=.8654).
The stratum analysis revealed that the active group subset
of subjects in the high total carbohydrate intake group had sig-
nifi cantly greater reductions in their waist sizes compared with
the placebo group. The active group lost 3.3 in from their waist-
lines, whereas the placebo group lost 1.3 in from their waistlines.
The between-group analysis was signifi cant, with a P value of
.0100. Again, none of the other strata for the total carbohydrate
intake subgroup and neither the BMI nor net carbohydrate
intake groups demonstrated any signifi cant differences between
active and placebo regarding reduction in waist size.
Other Effi cacy Parameters
Several other parameters were analyzed for changes from
baseline including hip size; triglyceride, fasting glucose, and total
cholesterol levels; appetite control; hunger; energy level; and
body fat percentage. There were no signifi cant differences seen
between groups or from baseline in any of these parameters even
when stratifi ed by BMI, total carbohydrate intake, or net carbo-
hydrate intake.
TABLE 1 Sociodemographic Characteristics, Baseline Glucose, and Total Cholesterol Levels by Study Group
Group Male (%) White (%) Married (%)
Education
BA MA MA+ N Glucose mean (SD) Total cholesterol mean (SD)
Active 54% 46% 54% 34% 8% 46% 13 91 (14) 214 (86)
Placebo 83% 58% 33% 67% 8% 8% 12 90 (7) 178 (42)
TABLE 2 Body Mass Index
Tertile Ranges and Number of Subjects
Range Number of Subjects
Min Max White bean extract Placebo Total
Low 23.70 25.30 3 5 8
Medium 25.44 26.80 5 4 9
High 27.10 30.08 5 3 8
TABLE 3 Mean Dietary Carbohydrate Intake
Tertile Ranges and Number of Subjects
Range
(grams per day) Number of Subjects
Min Max White bean extract Placebo Total
Low 57.13 58.43 3 5 8
Medium 58.61 59.55 5 4 9
High 60.19 61.63 5 3 8
TABLE 4 Net Dietary Carbohydrate Intake
Tertile Ranges and Number of Subjects
Range
(grams per day) Number of Subjects
Min Max White bean extract Placebo Total
Low 18.84 24.16 4 4 8
Medium 24.38 27.18 3 6 9
High 27.89 33.84 6 2 8
TABLE 5 Results: Weight Loss
Stratifi cation Active Placebo
Between-
Group Analysis
None -6.0 -4.7 P=.4235
Low body mass index -4.267 -4.96 P=.7573
Medium body mass index -3.6 -1.9 P=.5244
High body mass index -9.44 -8 P=.5283
Low total
carbohydrate intake -4.4 -3.9
P=.8884
Medium total
carbohydrate intake -5.8 -7.0
P=.5905
High total
carbohydrate intake -8.55 -1.65
P=.0412
Low net
carbohydrate intake -7.15 -7.0
P=.9179
Medium net
carbohydrate intake -7.733 -2.367
P=.1448
High net
carbohydrate intake -4.367 -7.1
P=.4359
36 ALTERNATIVE THERAPIES, jul/aug 2007, VOL. 13, NO. 4
A Fractionated White Bean Extract for Weight Loss
Safety and Compliance
No side effects or adverse events were reported during the
total trial period. Safety monitoring included kidney and liver
function tests as well as blood and platelet counts. There were no
signifi cant differences between the 2 groups at baseline for blood
screen data, nor were there any signifi cant differences from base-
line or between groups at the end of the intervention.
Compliance was determined through pill count and work-
out and therapy attendance. There were no signifi cant differenc-
es between groups on compliance. Compliance rated at above
95% for both pill consumption and exercise. Therapy sessions
had a compliance rate of 75%; attendance percentage was nearly
identical for each group.
DISCUSSION
This short-term, multi-component study demonstrates that
subjects who adhere to a program including dietary modifi ca-
tion, exercise, and group behavioral support for dietary compli-
ance can lose a signifi cant amount of weight in a relatively short
period of time. The inclusion of the white bean extract in addi-
tion to the multiple components of diet, exercise, and behavior
did not make a signifi cant group (active vs placebo) difference in
this short time frame.
The results of the exploratory analysis showed that when
the groups were stratifi ed by the total number of carbohydrates
that they ate, the tertile that ate the most carbohydrates did see
signifi cant differences in weight loss (8.7 lbs vs 1.7 lbs, P=.0412)
and waist size (3.3 in vs 1.3 in, P=.0100) when using the white
bean extract. If future subjects eat a larger percentage of carbohy-
drates and are able to diminish the effective caloric value of this
volume through the use of an alpha-amylase inhibitor such as the
white bean extract, then those subjects may experience a decrease
in weight and waist size greater than those who do not consume
as many calories from carbohydrates.
Possible limitations of this study include the fact that the
white bean extract or placebo was delivered with only 2 of the 3
meals per day. Carbohydrate intake was recorded on a daily basis
and not merely for the meals at which the white bean extract or
placebo was given. In addition, this was a very short study (4
weeks) and included only 25 subjects. The inclusion of the exer-
cise program and group behavioral support components may
have infl uenced groups differentially, though current data can
not confi rm this potential. The inclusion of the behavioral thera-
py component to address personal eating issues may have con-
founded results as well. Although subjects with overt eating
disorders were excluded from the study, the psycho-social issues
that accompany obesity are highly varied, and the effectiveness
of a behavioral intervention is diffi cult to quantify.
The trends identifi ed by this study in such a short time peri-
od need to be validated by further studies. A potential explana-
tion is that the white bean extract’s carbohydrate-blocking action
prevents absorption of more calories in people whose dietary
intake includes a larger proportion of carbohydrates than per-
sons whose dietary intake includes fewer calories from carbohy-
drates. This fi nding certainly should be explored further, as the
study included a very small range of appropriate carbohydrate
intake, which was monitored by daily diary records reviewed by
a registered dietician. Finding differences within such a small
range of variation requires further probing. As some promising
differentials for response to this therapy are reported here in this
preliminary study, ideally it would be followed up with a sample
in congruence with power calculation requirements to show effi -
cacy between groups. In subsequent studies, the total carbohy-
drate intake should match that of the high total carbohydrate
intake tertile from this study to determine whether the explana-
tion for differences are based on even small dietary intake differ-
entials. In addition, it might make physiological sense for the test
medication to be given at all meals throughout the day rather
than just 2 meals per day, as in this study.
Weight gain is truly a multi-factorial problem that encom-
passes the fi elds of endocrinology, psychology, nutrition, and exer-
cise physiology. This study attempts to combine the approaches of
these various disciplines and add a new variable in the form of
alpha amylase inhibition to decrease carbohydrate digestion.
These preliminary results from a subset of study subjects demon-
strate that the white bean extract may have the potential to be a
useful adjunct to traditional weight control methods; however,
longer studies with a larger pool of subjects are minimally required
before any defi nitive conclusions can be made. It was reported in
2005 that 60.5% of adult Americans were overweight, 23.9 % obese,
and 3 % severely obese.
15
Therefore, any additional knowledge
about a potentially helpful product for weight reduction is war-
ranted and should be investigated with more studies of greater
sophistication as funding allows.
TABLE 6 Results: Waist Size
Stratifi cation Active Placebo
Between-Group
Analysis
None -2.2 -2.1 P=.8654
Low body mass index -3.667 -2.4 P=.2351
Medium body mass index -0.7 -1.75 P=.5039
High body mass index -3 -2 P=.2031
Low total
carbohydrate intake -2.25 -2
P=.8876
Medium total
carbohydrate intake 0 -2.667
P=.1377
High total
carbohydrate intake -3.25 -1. 25
P=.0100
Low net
carbohydrate intake -2.167 -2.125
P=.9712
Medium net
carbohydrate intake -1.667 -2.25
P=.7387
High net
carbohydrate intake -2.5 -1.5
P=.5060
A Fractionated White Bean Extract for Weight Loss
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