title: Greater diet quality is associated with more optimal glycemic control in a longitudinal study of youth with type 1 diabetes.
abstract: BACKGROUND
  Despite the centrality of nutrition in the management of type 1 diabetes, the association of diet quality and macronutrient distribution with glycemic control is ambiguous.
  
  
  OBJECTIVE
  This study examined longitudinally the association of dietary intake with multiple indicators of glycemic control in youth with type 1 diabetes participating in a behavioral nutrition intervention study.
  
  
  METHODS
  Participants in a randomized clinical trial of a behavioral nutrition intervention [n = 136; mean ± SD age: 12.8 ± 2.6 y; glycated hemoglobin (HbA1c): 8.1% ± 1.0%; 69.1% using an insulin pump] completed 3-d diet records at baseline and months 3, 6, 9, 12, and 18; masked continuous glucose monitoring (CGM) data were obtained concurrently with the use of the Medtronic iPro CGM system. HbA1c was obtained every 3 mo; 1,5-anhydroglucitol was obtained every 6 mo. Linear mixed-effects regression models estimated associations of time-varying dietary intake variables with time-varying glycemic control indicators, controlling for age, height, weight, sex, Tanner stage, diabetes duration, regimen, frequency of blood glucose monitoring, physical activity, and treatment assignment.
  
  
  RESULTS
  HbA1c was associated inversely with carbohydrate and natural sugar, and positively with protein and unsaturated fat. 1,5-Anhydroglucitol was associated positively with fiber intake and natural sugar. Greater glycemic control as indicated by ≥1 CGM variable was associated with higher Healthy Eating Index-2005, whole plant food density, fiber, carbohydrate, and natural sugar and lower glycemic index and unsaturated fat.
  
  
  CONCLUSIONS
  Both overall diet quality and macronutrient distribution were associated with more optimal glycemic control. Associations were more consistent for CGM variables obtained concurrently with dietary intake than for biomarkers of longer-term glycemic control. These findings suggest that glycemic control may be improved by increasing intake of high-fiber, low glycemic-index, carbohydrate-containing foods. This trial was registered at clinicaltrials.gov as NCT00999375.
authors.affiliation: Health Behavior Branch and nanselt@mail.nih.gov.
authors.forename: Tonja R
authors.identifier: http://orcid.org/0000-0002-8298-7595
authors.initials: TR
authors.lastname: Nansel
authors.affiliation: Health Behavior Branch and.
authors.forename: Leah M
authors.identifier: http://orcid.org/0000-0003-2645-4388
authors.initials: LM
authors.lastname: Lipsky
authors.affiliation: Biostatistics and Bioinformatics Branch, Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD.
authors.forename: Aiyi
authors.initials: A
authors.lastname: Liu
mesh_terms: D000293:Adolescent; D001786:Blood Glucose / Q000378:metabolism*; D002648:Child; D003847:Deoxyglucose / Q000097:blood; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000178:diet therapy* / Q000188:drug therapy; D004032:Diet / Q000592:standards*; D015930:Diet Records; D004040:Dietary Carbohydrates / Q000008:administration & dosage / Q000494:pharmacology; D004042:Dietary Fats, Unsaturated / Q000008:administration & dosage / Q000494:pharmacology; D004043:Dietary Fiber / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use; D004044:Dietary Proteins / Q000008:administration & dosage / Q000494:pharmacology; D005260:Female; D006442:Glycated Hemoglobin / Q000378:metabolism*; D038321:Glycemic Index; D006801:Humans; D007328:Insulin / Q000627:therapeutic use; D008137:Longitudinal Studies; D008297:Male
chemical_list: D001786:Blood Glucose; D003847:Deoxyglucose; D004040:Dietary Carbohydrates; D004042:Dietary Fats, Unsaturated; D004043:Dietary Fiber; D004044:Dietary Proteins; D006442:Glycated Hemoglobin; D007328:Insulin; C006584:1,5-anhydroglucitol
keywords: continuous glucose monitoring; diet quality; glycemic control; type 1 diabetes; youth