The Effects of a Low Carbohydrate, Non-Ketogenic Diet Versus Standard Diabetes Diet on Glycemic Control in Type 1 Diabetes (T1DLoCHO)

• ClinicalTrials.gov Identifier: NCT03544892
• Recruitment Status: Terminated
• First Posted: June 4, 2018
• Last Update Posted: January 13, 2020
• Sponsor: University of Oklahoma
• Information provided by (Responsible Party): University of Oklahoma

Study Description

Brief Summary:

This randomized, crossover nutrition intervention seeks to examine the effects of a non-ketogenic low carbohydrate (CHO) diet (60-80g per day) on glycemic control, lipids, and markers on inflammation in individuals with Type 1 Diabetes (T1D). This study will be used to inform clinical practice, especially in teaching medical nutrition therapy to new-onset diabetes patients and those struggling with glycemic control and hyperlipidemia. At this time, no evidenced-based universal recommendations from randomized controlled trials exist to support low carbohydrate dietary patterns as a front-line approach in individuals with T1D. The investigators hypothesize a diet consisting of 60-80 g carbohydrate diet will result in greater improvement in glycemic control compared to a 50% carbohydrate diet in patients with Type 1 diabetes over 12 weeks in the outpatient setting.

Condition or disease	Intervention/treatment	Phase
Diabetes Mellitus, Type 1	Other: Low carbohydrate diet; Other: Standard of care diet	Not Applicable

Detailed Description:

Type 1 diabetes mellitus (T1D) is marked by total insulin dependence with challenges regarding glycemic control and concomitant sequela. While standard of care medical nutrition therapy for this disease centers on matching carbohydrate to insulin at meals, recent literature and clinical reports have shown superior glycemic control and cardiovascular measures with lower carbohydrate dietary patterns (<130g/day) as compared to the standard American MyPlate (50% total calories as carbohydrate) approach. Diabetes management has evolved tremendously in the last twenty years with the development of sophisticated insulin pumps and continuous glucose monitors; but, glycemic control is still dependent on quantification of carbohydrate, imperfect in the real-world setting. Due to inherent error in carbohydrate counting, the investigators propose that less carbohydrate will produce better glycemic control by minimizing error and subsequent variation in individuals with type 1 diabetes.

There has long been a movement in the medical community to prescribe low carbohydrate diets under the premise of "less carbohydrate, less insulin, less glycemic variation". This strategy centers on "the law of small numbers", a calculus principle describing magnitude of variation in the output (glycemic variation) as the function of input size (CHO + insulin). Carbohydrate counting tends to result in ~50% error while there is ~30% variation in insulin action, making exactitude impossible. However, low CHO diets tend to provide >40% energy from fat due to the macronutrient distribution. With innate risk of cardiovascular disease in T1D, standard of care has supported restriction of total fat consumption, especially saturated fat, in effort to control cholesterol. While the American Diabetes Association recognizes that dietary fat is a controversial and complex issue, eliminating trans-fats is the only consensus point across the field. To date, most low CHO diet studies in both T1D and Type 2 Diabetes (T2D) have not shown adverse effects on lipids and tend to show decreases in triglycerides and either no change or increases in HDL, LDL, and total cholesterol.

Study Design

• Study Type: Interventional (Clinical Trial)
• Actual Enrollment: 11 participants
• Allocation: Randomized
• Intervention Model: Crossover Assignment
• Intervention Model Description: This study uses 33 week randomized, powered study design to measure glycemic control with a low carbohydrate dietary pattern versus standard of care diabetes medical nutrition therapy. Each arm is 12 weeks with an 8 week washout between arms.
• Masking: None (Open Label)
• Primary Purpose: Treatment
• Official Title: The Effects of a Low Carbohydrate, Non-Ketogenic Diet Versus Standard Diabetes Diet on Glycemic Control in Type 1 Diabetes
• Actual Study Start Date: May 1, 2018
• Actual Primary Completion Date: June 28, 2019
• Actual Study Completion Date: June 28, 2019

Arms and Interventions

Arm	Intervention/treatment
Experimental: Experimental: Low carbohydrate diet	Other: Low carbohydrate diet; 60-80 g total carbohydrate per day
Active Comparator: Experimental: Standard of care diet	Other: Standard of care diet; > 150 g total carbohydrate per day

Outcome Measures

Primary Outcome Measures :

1. Time in Range [ Time Frame: 5 days of worn CGM during each intervention ]
   Difference in time spent with glucose values between 70-180 mg/dL assessed by continuous glucose monitoring (CGM)

Secondary Outcome Measures :

1. Mean Glucose [ Time Frame: Baseline to 12 weeks (1 week worn CGM data) ]
   Difference in mean glucose values assessed by CGM
2. Standard deviation of glucose [ Time Frame: Baseline to 12 weeks (1 week worn CGM data) ]
   Difference in standard deviation of glucose values assessed by CGM
3. Mean amplitude of glycemic excursions [ Time Frame: Baseline to 12 weeks (1 week worn CGM data) ]
   Difference in mean amplitude of glycemic excursions assessed by CGM
4. Time in hypoglycemia [ Time Frame: Baseline to 12 weeks (1 week worn CGM data) ]
   Difference in time spent with glucose values <70 mg/dL; between 55-70 mg/dL; and <55 mg/dL
5. Time in hyperglycemia [ Time Frame: Baseline to 12 weeks (1 week worn CGM data) ]
   Difference in time spent with glucose values >180 mg/dL
6. Change in HbA1c [ Time Frame: Baseline to 12 weeks ]
   Difference in change in hemoglobin A1c
7. Coefficient of Variation [ Time Frame: Baseline to 12 weeks (1 week worn CGM data) ]
   Estimate of glucose variability calculated by dividing the standard deviation by average glucose
8. Severe hypoglycemia [ Time Frame: Baseline to 12 weeks ]
   Difference in number of severe hypoglycemia episodes (glucagon or IV dextrose administration)
9. Total daily insulin dose [ Time Frame: Baseline to 12 weeks ]
   Difference in total daily insulin dose
10. Total daily basal insulin 24 hour [ Time Frame: Baseline to 12 weeks ]
    Difference in total daily basal insulin in 24 hours
11. Total daily bolus insulin 24 hour [ Time Frame: Baseline to 12 weeks ]
    Difference in total daily bolus insulin in 24 hours
12. Body weight [ Time Frame: Baseline to 12 weeks ]
    Change in body weight
13. Body Mass Index (BMI) [ Time Frame: Baseline to 12 weeks ]
    Change in BMI
14. Systolic Blood Pressure (mm Hg) [ Time Frame: Baseline to 12 weeks ]
    Change in systolic BP
15. Diastolic Blood Pressure (mm Hg) [ Time Frame: Baseline to 12 weeks ]
    Change in diastolic BP
16. Pulse, per minute [ Time Frame: Baseline to 12 weeks ]
    Change in pulse
17. Energy Intake (kcal/day) [ Time Frame: Baseline to 12 weeks ]
    Change in energy intake
18. Daily carbohydrate intake (total carbohydrate, g/day) [ Time Frame: Baseline to 12 weeks ]
    Change in carbohydrate intake
19. Percent energy intake as Carbohydrate [ Time Frame: Baseline to 12 weeks ]
    Change in % carbohydrate intake
20. Daily protein intake (total protein, g/day) and Daily fat intake (total fat, g/day) [ Time Frame: Baseline to 12 weeks ]
    Change in protein intake
21. Fat quality intake (% total fat as monounsaturated, polyunsaturated, saturated, omega-3) [ Time Frame: Baseline to 12 weeks ]
    Change in fat quality
22. Standard Lipid Panel [ Time Frame: Baseline to 12 weeks ]
    Change in (Total cholesterol, HDL cholesterol, LDL cholesterol-calculated, triglycerides; mg/dL)
23. LDL-P (nmol/L) [ Time Frame: Baseline to 12 weeks ]
    Change in LDL-P
24. HDL-P (umol/L) [ Time Frame: Baseline to 12 weeks ]
    Change in HDL-P
25. VLDL-P [ Time Frame: Baseline to 12 weeks ]
    Change in VLDL-P (nmol/L)
26. LDL size [ Time Frame: Baseline to 12 weeks ]
    Change in LDL size (nm)
27. HDL size [ Time Frame: Baseline to 12 weeks ]
    Change in HDL size (nm)
28. VLDL size [ Time Frame: Baseline to 12 weeks ]
    Change in VLDL size (nm)
29. High-sensitive C-reactive protein (hs-CRP) [ Time Frame: Baseline to 12 weeks ]
    Change in hs-CRP
30. Plasma lipopolysaccharide [ Time Frame: Baseline to 12 weeks ]
    Surrogate marker for inflammation
31. Serum Ketones (beta-hydroxybutyrate) [ Time Frame: Baseline to 12 weeks ]
    beta-hydroxybutyrate (mmol/L)
32. Type 1 Diabetes Nutrition Knowledge Survey [ Time Frame: Baseline to Week 33 (end of study) ]
    Validated nutrition knowledge survey (nutrition label reading, carbohydrate counting)
33. Diet Quality [ Time Frame: Baseline to 12 weeks ]
    Minerals, Vitamins, Dietary Fiber amounts compared to DRIs for age, ascertained by 3 day 24 hour food logs

Eligibility Criteria

• Ages Eligible for Study: 18 Years to 30 Years (Adult)
• Sexes Eligible for Study: All
• Accepts Healthy Volunteers: No

Criteria

Inclusion Criteria:

• Confirmed Type 1 diabetes for > 1 year confirmed by physician diagnosis
• HbA1c >5.9% and <10%;
• Confirmation of minimum three blood glucose tests per day (meter download or chart record)
• Use of continuous subcutaneous insulin infusion therapy (CSII) or multiple daily injection (MDI) intensive insulin therapy
• No change in insulin therapy type (CSII or MDI) in last 2 months or longer
• Willingness to count carbohydrate and use bolus calculator on insulin pump during the intervention periods
• Willingness to wear a 7 day CGM at three different time points during the study

Exclusion Criteria:

• Females of childbearing potential who are pregnant or intend to become pregnant, are exclusively breastfeeding, or who are not using adequate contraceptive methods
• Use of corticosteroids during or within 30 days prior to the intervention periods
• Macroalbuminuria
• Active proliferative retinopathy combined with an HbA1c ≥ 9%
• Known or suspected alcohol or drug abuse
• Other concomitant medical or psychological condition that according to the investigator's assessment makes the patient unsuitable for study participation

Contacts and Locations

Locations

United States, Oklahoma

University of Oklahoma Harold Hamm Diabetes Center

Tulsa, Oklahoma, United States, 74135

Sponsors and Collaborators

University of Oklahoma

Investigators

• Principal Investigator: Christina M Crowder, RDN, CNSC, LD; University of Oklahoma

More Information

• Responsible Party: University of Oklahoma
• ClinicalTrials.gov Identifier: NCT03544892
• Other Study ID Numbers: 8840
• First Posted: June 4, 2018
• Last Update Posted: January 13, 2020
• Last Verified: January 2020

• Studies a U.S. FDA-regulated Drug Product: No
• Studies a U.S. FDA-regulated Device Product: No

Keywords provided by University of Oklahoma:

Low carbohydrate diet

Additional relevant MeSH terms:

Diabetes Mellitus; Diabetes Mellitus, Type 1; Glucose Metabolism Disorders; Metabolic Diseases; Endocrine System Diseases; Autoimmune Diseases; Immune System Diseases