Biology Reference
In-Depth Information
incretin hormone secretion was stimulated and slowed gastric emptying
which led to a marked reduction in postprandial glycemia in type 2 diabetics
(
Ma et al., 2009
)
. This is in agreement with other studies showing that
whey is insulinotropic (
Nilsson et al., 2004
). In the study by
Akhavan
et al. (2010)
,
a whey hydrolysate which was used as a comparator did not
reduce blood glucose response compared to whey protein suggesting that
whole proteins also possibly stimulate noninsulinotropic hypoglycemic
pathways. Premeal protein ingestion may be a useful strategy for blood glu-
cose control in healthy and diabetic individuals. This is an area worthy of
further exploration.
The blood glucose lowering and insulinotropic effect of whey protein
was also seen in type 2 diabetic subjects. The addition of whey to high gly-
cemic index meals was found to improve blood glucose control in type 2
rapidly digested and absorbed carbohydrates supplemented with whey stim-
ulated insulin release and reduced postprandial blood glucose excursions
compared to the same meal which was supplemented with lean ham and
lactose in place of whey (
Frid et al., 2005
)
. Whey protein used in the test
meal also produced postprandial GIP responses which were higher than
when lean ham was used (
Frid et al., 2005
)
. A study by
Ang, Muller,
Wagenlehner, Pilatz, and Linn (2012)
on type 2 diabetics found no signif-
icant differences in glucose responses after ingestion of drinks containing
slowly digested isomaltulose with different protein types (i.e., fast-absorbing
whey/soy vs. slow-absorbing casein). But the results suggested that proteins
increased postprandial insulin and that insulin action was lower for the fast-
absorbing whey/soy than for slow-absorbing casein. A fast-absorbing pro-
tein mixture therefore does not appear to be beneficial for glycemic control
in type 2 diabetic patients as it reduces insulin action to a greater extent than
slow-absorbing proteins. Fast and slow absorbed dietary proteins have also
shown to have dissimilar digestion kinetics (Bos et al., 2003) and differen-
tially affect protein anabolism and oxidation (
Boirie et al., 1997
)
. Therefore,
the absorption rate of proteins appears to have significant implications in
insulin secretion and glucose metabolism (
Calbet & Maclean, 2002
)
.
Using healthy individuals
Karamanlis et al. (2007)
compared the
glycaemic response to drinks containing either glucose, gelatin or glucose+
gelatin
Karamanlis et al. (2007)
.
The blood glucose response was less after
glucose
þ
gelatin than after glucose alone. The study also showed that gastric
emptying rate was lowest when proteins and carbohydrates were coingested.
The rate of gastric emptying and incretin, hormone (GLP-1 and GIP)