In conclusion, white bread enriched with GTE and BAO
showed no effect on GR or satiety, yet BAO was shown to
increase insulin economy. This is the first study to look at the
effect of the addition of polyphenol-rich extracts into white
bread and the effects on GR, IR, and satiety in humans.
Limitations of this study include (1) the lack of an HPLC
method for analyzing the individual polyphenols present in
the different extracts, (2) no polyphenol analysis performed
after the extracts had been baked into the bread, and (3) the
use of subjective VAS to determine satiety. It must be noted
that this study is not attempting to promote the consumption
of white bread, but rather favoring the enhancement of the
quality of white bread for those who already commonly
consume it. The reduction in IR after BAO may be due to the
polyphenol association with carbohydrate digestion, or to the
absorbed compounds from the extracts altering insulin action
in the body. Relatively low doses of extracts were used in this
study, and therefore, the improvement in insulin parameters
is of great significance. Although the dose was low, extracts
were baked into bread and therefore may have directly
interacted with starch chains requiring a lower amount to
show a positive effect on glycemic parameters. However,
higher doses of extracts may be needed to see a reducing
effect on GR. Because of the conflicting results from previous
studies in our laboratory which found BAO to reduce starch digestion in vitro with no effect on GR in the current study,
further research needs to determine the effects of different doses of BAO both in solid and liquid mediums, and the effect this has on GR and IR.