Biology Reference
In-Depth Information
compared to whey to study if the former would have similar or better
insulinotropic properties than the latter in healthy subjects (
Nilsson,
and insulinemic responses as whey with no additional effects of GIP and
GLP-1. An increased insulin-stimulated glucose disposal and reduced post-
prandial glucose concentration was observed in type 2 diabetics when they
coingested a carbohydrate with a mixture of casein hydrolysate and amino
acids (leucine and phenylalanine;
Manders, Koopman, et al., 2006; Manders,
Praet, et al., 2006; Manders et al., 2005
). In another study, a beverage con-
sisting of an amino acid mixture and carbohydrate (isoleucine, leucine, cys-
teine, methionine, valine
þ
100 g dextrose) was compared to a control
(100 g dextrose only) to observe if there was an improvement in the glucose
response of healthy overweight subjects to an oral glucose tolerance test
(OGTT;
Wang et al., 2012
)
. Interestingly, plasma glucagon was significantly
higher than the control treatment, but a reduction in plasma glucose
response was also observed. There were no differences in the plasma insulin
responses between treatments. The amino acid mixture appeared to lower
the glucose response to an OGTT in subjects in an insulin-independent
manner which was consistent with
Nuttall, Schweim, et al. (2008)
and
in vitro
studies (
Doi, Yamaoka, Fukunaga, & Nakayama, 2003; Nishitani
et al., 2002
). The insulinotropic properties of protein and/or amino acid
mixtures (with a carbohydrate) could have clinical significance in the treat-
ment of type 2 diabetes by accelerating blood glucose disposal through both
insulin-dependent and -independent mechanisms.
In summary, the literature shows that amino acids alone have little effects
on blood glucose and insulin. However, some such as BCAAs, glutamine,
and phenylalanine have glucose and insulin modulating effects when given
alone. Amino acids when consumed in combination with carbohydrates
show greater effects on blood glucose and insulin. Specific amino acids
showing notable effects are arginine, proline, phenylalanine, glutamine,
and BCAAs.
6. CONCLUSIONS
The review reaffirms the notable effects proteins and amino acids exert
on insulin and glycemia. Proteins and amino acids influence insulin secretion
and glycemic control by directly stimulating
b
-cells and activating insulin
secretary mechanisms, by stimulating incretin responses, modulating
