5. Discussion
This study demonstrated that, in contrast to widely accepted
by public, the effect of white bread on the increase of blood
glucose level of patients with type 2 diabetes mellitus was not
different than other types of bread.
Many studies have shown that diets with lower glycemic
indices and higher fiber content decrease the risk of devel-
oping type 2 diabetes and heart diseases, contribute to a higher
life quality for diabetics and have some preventive and
curative effect against insulin resistance and metabolic
syndrome [1–3]. Cereal grains are recommended for diabetic
patients for their diets [4]. The cereal grain consists of
endosperm, embryo and bran. Grinding process separates
the bran and the embryo from the endosperm. The endosperm
is rich in starch content. Other nutrients are concentrated on
the outer layer of the grain. Consequently, nutritional content
of the refined grain decreases and contains more starch. The
major difference between whole grain food and refined grains
is that in whole grain food, the bran and the germ are
protected [5]. Viscous fibers, such as b glucan in oat bread
delays gastric emptying and causes glucose to be released into
the circulation more slowly [6,7]. Be cause of slower digestion
of cereals with high grain content, they may elevate
postprandial blood glucose less in diabetics [8]. Particle size
of whole grain cereals is one of the factors that define their
physiological effects. Unprocessed bran delays gastric empty-
ing and accelerates transit through intestines [9]. In our study,
blood glucose change showed a similar curve for all groups,
peaking at the 90 min. Therefore, no absorption difference as
affected by contents was considered between the compared
bread types.
There are other studies suggesting that different types of
bread do not differ in terms of glycemic effect in single meal
tests. Liljeberg et al. reported that in single meal tests,
glycemic and insulinemic responses to cereal products based
on whole—meal oats or barley were indistinguishable from
those with white bread [10]. Glycemic index value may be
found to vary between individuals, and between measure-
ments repeated for different individuals. We observed inter-
individual variability of glycemic responses for white bread.
Vega-Lopez et al. reported that interindividual variability is
higher than intraindividual reproducibility of glycemic index
values for commercial white bread [11].
The power of our study is that, the number of patient
groups was greater than that of similar studies, and every
patient in each group ate also white wheat bread. Since
patients ate white wheat bread on the day following the very
first day, possibility of any change in lifestyles or metabolic
variation is relatively low.
The weakness of our study, on the other hand, is that
consumed bread types do not suggest any effects other than
short-term glycemic and insulinemic effects. The absence of
any significant difference in postprandial insulin levels
between four type of breads in our study does no