Low glycemic index diet and other strategies may yield better results
Carbohydrate counting is the recommended dietary strategy for achieving glycemic control in people with type 1 diabetes. This recommendation is based on narrative review and grading of the available evidence such as a 2009 study which found carbohydrate counting and increased blood glucose monitoring were associated with lower A1C in children with type 1 diabetes.
Dr. Jeannie Brand-Miller, PhD, FAIFST, FNSA, researcher, biochemistry professor and holds a Personal Chair in Human Nutrition in the School of Molecular Biosciences at the University of Sydney, along with colleagues examined the efficacy of carbohydrate counting on glycemic control in adults and children with type 1 diabetes by conducting a systematic review and meta-analysis of randomized controlled trials that were longer than three months that compared carbohydrate counting with general or alternate dietary advice in adults and children with type 1 diabetes.
The team searched all relevant data bases including Medline, Embase, and Cochrane Central Register of Controlled Trials. The team identified seven eligible trials of 311 potentially relevant studies, comprising 599 adults and 104 children with type 1 diabetes. The studies quality score averaged 7·6 out of 13.
A sub analysis of five parallel design studies in adults did show carbohydrate counting to be more useful for lowering HbA1c than standard care (0.64% point [7.0 mmol/mol] HbA1c reduction; 95% CI minus 0.91-minus 0.37: P<0.0001).
Overall there was no significant improvement in HbA1c concentration with carbohydrate counting versus the control or usual care (−0·35% [−3·9 mmol/mol], 95% CI −0·75 to 0·06; p=0·096).
According to Dr. Brand-Miller “This was a significant difference in HbA1c that most people would consider clinically important.” “But the question remains, ‘Is five studies with flawed study designs enough to make carbohydrate counting the gold standard?”
In their interpretation the team writes “There is some evidence to support the recommendation of carbohydrate counting over alternate advice or usual care in adults with type 1 diabetes. Additional studies are needed to support promotion of carbohydrate counting over other methods of matching insulin dose to food intake.”
Dr. Brand-Miller adds that the evidence is clear that counting carbohydrates does provide a moderate improvement in glycemic control over usual care however, it is not clear if other strategies such as following a low-glycemic index diet could result in better patient outcomes.
This study appears in The Lancet Diabetes & Endocrinology