Galactose - the Ideal Carbohydrate Supplement for Exercise in Type 1 Diabetes

Study Overview
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Brief Summary
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In this study, 14 subjects with type 1 diabetes are studied in a randomized crossover study in which the subjects cycle at a fixed intensity at 60% of their maximum oxygen capacity (VO2 max) for 1 hour. Thirty minutes before each cycling test, participants consume a 200 ml beverage, consisting of either: 1) dextrose (20 g), 2) galactose (20 g), 3) lactose (20 g) or 4) water (sweetened). If blood sugar drops below 3.9 mmol/l, glucose infusion is given and blood sugar is kept just above 5 mmol/L. The trial days take place at least 4 days apart.

Detailed Description
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On study days, a catheter is placed in two antecubital veins for regular blood sampling and for glucose infusion (if needed). The participant will rest in a bed, when not performing the 1-hour bicycle ergometer test. Thirty minutes before the leg-cycle ergometer test, the participants consume a 300 ml beverage containing either: 1) dextrose (20 g), 2) galactose (20 g) 3) lactose (20 g) or 4) water (sweetened). At t=0, the ergometer test is started and continued for 1 hour (fixed intensity cycling at 60% of VO2-max). If blood glucose drops below 3.9 mmol/l, glucose infusion (5 % glucose) will be administered, and blood glucose is kept just above 5 mmol/l and infused volume is registered. Blood samples are collected at t= -40, 0, 30, 60, 90, 120 for measurement of plasma lactate, non-esterified fatty acids (NEFA), plasma triglyceride and hormonal concentrations (epinephrine, norepinephrine, cortisol, and glucagon). Plasma blood glucose measurements are performed at t = -40 and every 10-15 minutes until the end of the study day. Respiratory exchange ratio is measured by indirect calorimetry (collection of respiratory gasses VO2 and VCO2) pre-exercise, at the end of the exercise bout, and 30 minutes post-exercise. Protein oxidation rate is estimated from urinary urea excretion, and net lipid and glucose oxidation rates are calculated from indirect calorimetry measurements with correction for protein oxidation. Therefor a urine sample will also be collected at the end of the study day. The bicycle ergometer test is discontinued after 1 hour of bicycling and the participant is observed until 2 hour post exercise where the study day is ended.

Official Title
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Galactose - the Ideal Carbohydrate Supplement for Exercise in Type 1 Diabetes

Conditions
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Type1diabetes, Hypoglycemia, Hyperglycemia

Intervention / Treatment
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* Other: 1-hour cycling


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: type 1 diabetes for at least 2 years age between 18 and 65 years HbA1c less than 70 mmol/mol Physically active (at least 150 minutes of moderate-to-vigorous intensity activity weekly) Insulin pen and pump treatment Men and women are eligible, but women will have to perform study days in the mid-cycle phase of the menstrual cycle. Exclusion Criteria: - Diabetic nephropathy, neuropathy, and proliferative retinopathy Hypoglycemia unawareness Lactose intolerance Heart disease and other conditions which may be negatively affected by the VO2 max test and 1-hour cycling on study days

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: The study is a single-blinded, randomized crossover study, consisting of 4 study days of 1-hour fixed intensity cycling, after consumption of either galactose, lactose, glucose or water.
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Galactose<br>30 g in 200 ml liquid | Other: 1-hour cycling<br>* 60 % VO2 max<br>|
| Experimental: Lactose<br>30 g in 200 ml liquid | Other: 1-hour cycling<br>* 60 % VO2 max<br>|
| Experimental: Dextrose<br>30 g in 200 ml liquid | Other: 1-hour cycling<br>* 60 % VO2 max<br>|
| Experimental: Water<br>200 ml liquid sweetened | Other: 1-hour cycling<br>* 60 % VO2 max<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Time to hypoglycemia Secondary endpoints: Blood glucose variability, volume of intravenous glucose needed to maintain glucose above 5 mmol/l, respiratory exchange ratio. | time to blood glucose < 3.9 mmol/l | during and 2 hours after the bicycle test | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Blood glucose variability | Change in blood glucose (mmol/l) over time | during and 2 hours after the bicycle test | 
| Glucose infusion | Volume of intravenous glucose needed to maintain glucose above 5 mmol/l | during and 2 hours after the bicycle test | 
| Respiratory exchange ratio | RER is measured to to assess carbohydrate and lipid metabolism | prior, during and 2 hours after the bicycle test | 
| Time in Range | Time spend with a blood glucose between 3,9 mmol/l and 10 mmol/l | prior, during and 2 hours after the bicycle test |