Biology Reference
In-Depth Information
require investigation in future work. The protein source also appeared to
determine the nature of the metabolic response presumably due to differ-
ences in amino acid composition.
Protein source and composition appears to affect blood glucose concen-
trations and this was evident in a study where different beverages were con-
sumed in isovolumetric amounts before a meal. Milk (2% fat) resulted in the
lowest postmeal blood glucose compared to other beverages such as soy,
chocolate milk (1% fat), orange juice, and cow's milk-based infant formula
(
Panahi et al., 2013
)
. Milk (2% fat) had higher carbohydrate content than soy
beverage, but the higher protein content in the former (18 g vs. 14 g)
suggested that the amount and composition of protein played a role in post-
prandial blood glucose. The chocolate milk (1% fat) had similar sugar con-
tent as orange juice but had a greater blood glucose lowering effect. This
study showed the significant glucose lowering effects of milk protein. Earlier
studies have shown that milk protein stimulates an increase in postprandial
insulin response with corresponding reduction in postprandial blood glucose
levels (
¨
stman, Liljeberg, & Bj¨ rck, 2001
)
. The glycemic and insulinemic
effects of human and bovine milk was compared with white wheat bread in
In addition to human and bovine milk, subjects were also served test meals
consisting of reconstituted bovine whey or casein protein. All test meals
were standardized in terms of lactose content (25 g). Human milk showed
the lowest insulin response in comparison to other meals and the bovine
whey meal was the highest. Human milk was more insulinotropic per unit
protein compared to bovine milk, possibly due to the higher proportion of
whey protein. Positive correlations were seen between individual plasma
amino acids and serum insulin and plasma incretion secretion in the post-
prandial phase, as well as negative correlations with the glycemic response.
This suggests that amino acids play an important role in the insulinotropic
properties of milk proteins and contributes to the observed lower postpran-
dial glycemia. Although human milk has a lower protein content than
other milk types it is rich in whey protein. Human whey protein is a potent
GLP-1 secretagogue rendering it stronger insulinogenic properties than
bovine whey.
Glucose and insulin responses were observed in healthy women follow-
ing consumption of isocaloric meals containing protein from cod, bovine
milk, or soy
(
Von Post-Skagegard, Vessby, & Karlstrom, 2006
). The cod
protein meal had a larger insulin response AUC than the soy protein meal.
The serum insulin response showed a larger AUC for the milk protein meal
