Background
Amylase is a digestive
tract enzyme, which breaks down starch into small
units capable of being further degraded
to glucose, which is used for fuel for normal metabolism
and body homeostasis. Clinical use of inhibitors
of
amylase activity has widespread appeal because a controlled
reduction of starch digestion could influence carbohydrate
uptake in diabetes and obesity, the latter of which
is a current problem with 20% of the US population.
Of course obesity is also linked to a greater risk
of
diabetes. A search in the National Library of Medicine
Database reveals that there are 1098 articles concerning
amylase inhibition. About 15 years ago there were
a
number of articles concerning the use of commercial
bean-derived extracts. Also there were several articles
indicating that some of these products, which were
good
in vitro inhibitors, were not effective when given
to humans. Possible reasons for this failure were
1) insufficient
activity; 2) destruction in the gastrointestinal tract;
3) suboptimal pH conditions; and 3) different gastric
emptying rates of starch and inhibitor. A comprehensive
experimental investigation by a group at the Mayo
Clinic
in 1985 found that the major reason commercial bean
amylase inhibitors have failed to influence starch
digestion
in humans is their low antiamylase activity. Some inhibitors
also have side effects such as diarrhea and an increase
in intestinal gas. We have investigated the effectiveness
of a new commercial bean extract (Phase 2® )
prepared by Pharmachem Laboratories using normal human
subjects.
Protocol
Five males and five females
(ages 21 to 57) participated in a double-blind placebo
controlled crossover study
with informed consent. All subjects were employees
at a commercial clinical laboratory and went about
their
duties as secretaries and technicians during the study.
After an overnight fast, the participants were sampled
for blood and then given in a random manner either
1)
placebo consisting of 4 slices of white bread (60 grams
of carbohydrate), 42 grams of soybean oil margarine
and 4 grams of Sweet N'Low spread on the bread; 2)
experimental
comprising the placebo plus 1.5 grams of Phase 2® prepared
by Pharmachem Laboratories. Plasma glucose wasmeasured,
by a commercial enzyme kit (Sigma Chemical
Company), from blood drawn at baseline every 30 minutes
for 4 hours. After 1 week the regimen was repeated
with
the other supplement.
Results and Discussion
The subjects were normoglycemic
as measured by fasting glucose concentration, which
averaged 98 mg/dl for the
placebo and 104 for the Phase 2® . From 60 to
120 minutes (as seen in the accompanying figure) the
change in plasma glucose of the Phaseolamin™ group from
the baseline was ½ to 1/3 of the level of the
placebo group. Phaseolamin™ consumption caused the plasma
glucose to return to baseline values 20 minutes earlier
than the placebo without Phaseolamin™. The average area
under the plasma glucose-time curve from 0 to 150 minutes,
which is a measure of absorption and metabolism, was
57% lower with Phaseolamin™. Plotting the average change
in glucose concentration from 30 minutes to 210 minutes,
the area under the curve was positive for the placebo
but negative for Phase 2® . This indicates that
very little of the glucose from the starch in the bread
was absorbed when co-ingested with Phase 2® and the glucose was cleared very rapidly. No side effects
were observed with this product. The promising positive
preliminary results of this single dose pilot study
need to be confirmed. More control of physical activity
is required to decrease the variability of plasma glucose
between subjects. Ingestion of Phase 2® with
a conventional meal should be examined. Other groups
such as diabetic and obese should be studied with a
single dose and also in a long-term supplementation
study.
