To the best of our knowledge, this is the first study
where human milk is evaluated with respect to glycemic
and insulinemic effects. The study was performed in
healthy adults with a GI setting, thus post prandial glycemic
and hormonal responses to the human and bovine
milk were compared to an equicarbohydrate amount of
WWB. In the present study, we found that human milk
displayed insulinogenic properties and resulted in a postprandial
glycemic response (GI 57) that was in the same
range as that to bovine milk (GI 43) or the whey and casein
fractions, respectively (GI 61 and 44). The human
milk showed the lowest insulin response (iAUC 0–120
min) in comparison to all the other meals, thus indicating
that human milk display superior insulin economy.
Worth emphasizing is that the protein content of the
human milk meal was markedly lower than that of bovine
milk, whey and casein meals. According to our analysis,
the human milk meal contained 3.5g protein as
calculated from nitrogen analysis using 6.38 as conversion
factor. However, it has been has reported that the
true protein content of human milk is overestimated
from nitrogen analysis due to its high non protein nitrogen
(NPN) content (20-25% of total nitrogen) [16,17].
Consequently, the protein amount in the human milk,
used in this study, may have been overestimated. Although
the whey:casein ratio of the human and bovine
milk in this study was not analyzed, it has been reported
to range from 50:50 – 80:20 in human milk depending
on the lactation period [17], compared to approximately
20:80 in commercial bovine milk [16]. Our results thus
indicate that human milk may be more insulinogenic
per unit protein compared to bovine milk, and the higher proportion of whey protein may be a contributing
factor.