While the use of glycemic index to guide carbohydrate choice has been criticized as minimally beneficial (10
), these findings indicate that it has utility for improving glycemic control to a clinically meaningful degree above that obtained by careful carbohydrate counting and contemporary insulin regimens. The LGI diet resulted in significantly lower mean daytime BG, as well as lower scores on two indexes of high BG risk, both which have been associated with A1C (11
). This effect was observed despite a greater actual amount of carbohydrate being consumed per unit of insulin in the LGI condition. The absence of a difference in nighttime parameters supports the understanding that an LGI diet effects BG through reduction of post-prandial excursions.
It is notable that a greater frequency of mild hypoglycemia was observed during the LGI condition. Therefore, insulin dose on an LGI diet may need to be reduced to prevent excessive hypoglycemia. Consistent consumption of an LGI diet may reduce insulin requirement while improving BG control, but careful attention should be given to BG monitoring and adjustment of insulin dose.
Strengths of this study include 1) the use of CGMS to capture the BG profile, 2) a controlled setting to ensure compliance and consistency across conditions, and 3) a sample of youth using insulin-to-carbohydrate regimens. Primary limitations are the study’s short duration and small sample size, precluding assessment of effect modification by disease duration or pubertal status.
This study adds to the evidence supporting the utility of an LGI diet in optimizing diabetes management. Furthermore, considering the prevalence of cardiovascular risk factors in youth with diabetes (13
) and the increasing prevalence of comorbid type 2 diabetes (14
), the additional benefits of an LGI diet shown in previous research (15
) are also highly relevant. Promoting LGI eating may offer substantial health benefits to people with type 1 diabetes.