Biology Reference
In-Depth Information
that show low-GI values for oat meal porridge, this study resulted in a high-
GI value. The instant mashed potato also showed a high-GI value similar to
some of the previous studies. The study thus supported others reiterating the
efficacy of capillary blood sampling and the repeated testing of the reference
food, glucose or white bread, at least twice.
Table 5.3
summarizes the studies
that used cereal-based ingredients for modulating blood glucose in healthy
subjects, and
Table 5.4
illustrates the effect of cereal-based ingredients on the
blood glucose levels in type 2 diabetic subjects.
7. FRUIT-BASED INGREDIENTS
Other sources of polyphenols are also known to affect blood glucose in
healthy and diabetic subjects. The effect of polyphenol-rich fruits is some-
times more evident in the insulin response than on glycemia. A fermented
oatmeal drink enriched with 47% bilberries has been shown to reduce insu-
demand was attributed to increased glucose uptake, which is characteristic
of some other fermented products as well. The presence of polyphenols such
as anthocyanins may also have induced an effect on an enhanced insulin-
independent pathway for glucose uptake similar to the one reported for
cinnamon and other berries.
Polyphenols are present in abundance in a number of fruits and vegeta-
bles. Adding extracts of berries to various foods may be a useful and viable
strategy to attenuate blood glucose and insulin response. One of the earlier
studies was on the effect of berries on glycemic response to sucrose. A berry
puree (150 g) made of bilberries, blackcurrants, cranberries and strawberries,
and sweetened with 35 g sucrose was given to healthy subjects and com-
pared with 35 g sucrose alone mixed with fructose and glucose to match
the sugar composition (
T¨ rr¨nen, Sarkkinen, Tapola, Hautaniemi, &
Niskanen, 2010
). Although the mechanisms behind this result are not clear,
it may be attributed to the high-fiber content and polyphenol content of the
berry meal. However, a similar study using berries with pancakes did not
show any effect on glycemic response (
Clegg, Pratt, Meade, & Henry,
2011
). Although the authors used control pancakes with matched sugar pro-
file, they themselves had low GI indicating the effect of another ingredient,
probably fat or protein, in the pancakes that lowered its GI. The study did
not show any effect of the berries probably due to the masking effect of fat
present in the pancakes. Hence, there is a need to carefully look at the inter-
action between various ingredients present in the test meals while designing
a trial to look at the effect of specific compounds such as polyphenols. The
