I have been trying to learn more about the glycemic index and how it might relate to my daughter’s (who has type 1 diabetes) blood sugars. We often use 4 ounce juice boxes (apple or grape) to treat a low blood sugar, and I see that apple juice only has a glycemic index of 58 while a piece of bread is 100. Does this mean that a piece of bread will raise her blood sugar quicker than apple juice?

You are quite right that a piece of bread will raise your daughter’s blood glucose faster than the equal number of carbohydrate grams in apple juice. This means that bread helps to raise blood glucose when your daughter’s blood glucose goes too low. Please see The Glycemic Index or my new book, What Makes My Blood Glucose Go Up And Down? However, glucose is even faster, so I recommend that you always have glucose tabs handy. See Hypoglycemic Supplies.

DM
Additional comments from Joyce Mosiman, diabetes dietitian:
Theoretically it does mean that the effect on blood glucose if eaten in the amounts tested that bread has a greater effect than an equal amount of carbohydrate in juice. However, juice is liquid and will be processed more quickly than a slice of bread which must be broken down and converted to glucose first.

We are really just beginning to delve into the

glycemic index

and it’ implications for use in controlling blood glucose. As a dietitian, I would be concerned if people left out entire
food groups due to the GI. It is important to select foods from all the food groups and be aware of what the food does to a particular
individual.

JM