Biology Reference
In-Depth Information
turkey, and margarine. They found reduced glycemic response to apple and
banana test meal compared to the other fruits. In a later study in type 2
diabetic subjects, when raisins were compared with white bread, seedless
grapes, and banana, the glycemic response of raisins and banana was com-
parable whereas the seedless grapes had higher glycemic response (
Wilson
et al., 2012
). The authors believed that this effect may have been due to
the high water content of seedless grapes that accelerated the gastric empty-
ing rates and thereby resulted in rapid absorption of glucose into the blood
stream. The white bread's glycemic response was similar to the raisins
and bananas due to the effect of freezing and thawing on resistant starch
formation or starch retrogradation in bread.
TheGI of fruitsmay be affected by various factors such as degree of ripeness,
type of sugars present, other polyphenols present, the presence of fiber, and also
the acidity of the fruit as well as the physical structure of the fruit.When the GI
of chico, mango, pineapple, and papaya were tested in type 2 diabetes subjects,
mango and chico showed lower GI compared to papaya and pineapple. Trop-
ical fruits are generally reported to be of high GI values compared to the tem-
perate fruits. The amount of antinutrients such as phytic acid, tannins, lectins,
saponins, etc. can result in a lowglycemic response due to reduced rate of diges-
tion
(
Guevarra &Panlasigui, 2000
)
. Acids such asmalic, citric, and tartaric acids
present in fruits are also known to reduce their glycemic response.
Cranberries are also another group of fruits that are rich in polymeric
polyphenols such as proanthocyanidins. Wilson et al. experimented the
use of raw and dried cranberries against a white bread control in type 2 dia-
betics. The dried cranberries included a sweetened version using sugar and
also a low-sugar version with polydextrose. The plasma glucose was low for
the raw cranberries whereas the plasma insulin response was low for the raw
cranberries and for the low-sugar-dried cranberries in comparison with the
white bread and the dried sweetened cranberries (
Wilson et al., 2010
)
. Cran-
berry juice has also been shown to influence the glycemic response in dia-
betic subjects. However, there was a significant difference in the effect
between a conventional sweetened version and a low calorie version of
the juice
(
Wilson, Meyers, Singh, Limburg, & Vorsa, 2008
). However,
this study could not substantiate the effect of the polyphenols identified
in the cranberry juice such as quercetin, myricetin, anthocyanins, and
proanthocyanidins because the low-calorie control with dextrose also
resulted in a low glycemic response compared to the normal calorie version
of the juice and control.
A bioflavonoid extracted from sugar cane has been shown to decrease the
GI of a high-GI meal of milk and wheat biscuits. This specific flavonoid that
