My son’s blood test for celiac came back positive so we are not waiting for a biopsy. My son uses a CGMS as well as an insulin pump and I’ve noticed that when he eats pasta, he needs all the insulin up front and then, about four hours later, I must then set an extended bolus for about another 50 grams of carbohydrates over four hours to cover the “second hit.” This always happens with pastas and simply setting a combination bolus will not work. Could this be a sign of delayed absorption caused by celiac? He has no other symptoms of celiac and is growing normally with lots of energy. Should I be worried about a celiac diagnosis?

Celiac co-exists with about 6 to 10% of kids with type 1 diabetes. It is also more common with other endocrine autoimmune disorders such as thyroiditis and Addison’s. So, good for your doctors for screening even in someone asymptomatic. It is what we also do routinely. If he had positive antibodies, there should also be some testing for iron deficiency and poor iron stores, vitamin D abnormalities and osteopenia. Finally, if you find one person with celiac antibodies, the rest of the family should also be screened since much higher chance others will also be positive and asymptomatic.

However, what you are describing is pretty common with pasta and other “slow carbohydrates” and this can be elegantly demonstrated reproducibly with a CGM. On an insulin pump, therefore, one must use temporary basals to compensate. Sometimes the dual or square waves can also work, but these may not be quite long enough. Some trial and error adjustments of insulin would help, including some manual bolus a few hours after the meal, dosing after rather than before the meal or sometimes being sure to just dose and bolus 15 minutes ahead of the meal – all would depend on the exact nature of the curves upward. I do not think that this is related to celiac at all, but just the pasta effects. It may also have something to do with the fattiness of the pasta meal slowing down absorption in addition to intrinsic effects of pasta. The only thing much slower is pizza itself which tends to take almost two hours before it causes the glucose levels to rise – but then lasts for four to six hours instead of two to four like the pasta.

SB