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.