One
of the more recent areas of health benefit to be documented in strawberry
research is the area of blood sugar benefits. Several recent studies have found
regular intake of strawberries to be associated with decreased risk of type 2
diabetes. In some of these studies, frequency of strawberry intake definitely
seems to matter since an intake frequency of once per week or less is not
associated with blood sugar benefits in some studies. In these studies,
significant benefits do not emerge until frequency of intake reaches at least
2-3 strawberry servings per week.
Of special interest for blood sugar regulation is the
relationship recently documented by researchers between intake of strawberries,
intake of table sugar, and resulting blood sugar levels. As you might expect,
excess intake of table sugar (in a serving size of 5-6 teaspoons) was able to
produce an unwanted blood sugar spike in study participants during this study.
But as you might not expect, this blood sugar spike was actually reduced by
simultaneous consumption of strawberries. Approximately one cup of fresh strawberries
(approximately 150 grams) was able to decrease blood sugar elevations when
table sugar was consumed along with strawberries.
The investigators speculated
that polyphenols in strawberries played a major role in helping regulate blood
sugar response. One particular type of polyphenol in
strawberries—ellagitannins—might have been especially important for this blood
sugar-relating benefit. Ellaginannins are polyphenols that are known to inhibit
the activity of an enzyme called alpha-amylase. Since this enzyme is
responsible for breaking amylose starches into simple sugars, fewer simple
sugars might be released into the blood stream when activity of this enzyme is
reduced.
