Very Low Carbohydrate Diets and Glucagon Response in T1DM

ConditionType1diabetes
Trial statusRecruiting
Trial phaseNot applicable
Trial typeInterventional
Biological sexAll
Age18-40
SponsorBoston Children's Hospital

About this trial

Despite major technological advances, management of type one diabetes mellitus (T1D) remains suboptimal, putting millions of people at risk for immediate and long-term complications. After meals, a mismatch between carbohydrate absorption rate and insulin action typically leads to alternating periods of hyper- and hypoglycemia. A conceptually promising approach to control both problems is dietary carbohydrate restriction to reduce postprandial blood glucose changes and insulin needs. In a prior survey study, the investigators documented exceptional glycemic control (HbA1c 5.67%) and low acute complication rates among 316 children and adults with T1D consuming a very-low-carbohydrate (VLC) diet. Despite these promising preliminary results, the use of VLC diets for T1D remain controversial, because of their restrictive nature and theoretical concerns regarding growth, ketoacidosis and hypoglycemia risks and efficiency of glucagon treatment for hypoglycemia. Glucagon is used as a rescue medication during severe hypoglycemia and increases blood glucose levels by mobilizing liver glycogen stores. If these stores are depleted during carbohydrate restriction, glucagon response may be inadequate and put individuals at risk for refractory hypoglycemia. A physiologic study has shown a blunted but still adequate response to glucagon in n=10 participants after following a VLCD for 1 week. Longer-term studies have not been done.

To test the hypotheses that glucagon response remains adequate while following a VLC diet in the longer term, the investigators will conduct a glucagon challenge in participants who are assigned to the VLC arm of a randomized-controlled feeding study in 32 young adults with T1D who will receive a VLC vs a standard diet for 12 weeks. After an overnight fast, twelve participants in the VLC arm will receive IV insulin to lower blood glucose levels to 60 mg/dL, followed by a glucagon injection and monitoring of blood glucose levels and other metabolic fuels.

Eligibility criteria

This trial does not accept healthy volunteers

Qualifiers

Males and females with T1D for at least 1 year

Age 18 to 40 years

Tanner stage ≥ IV

BMI 18.5-35 kg/m2

Disqualifiers

Ketoacidosis or severe hypoglycemia with seizure or coma in the past 6 months

Dietary restrictions or intolerances that are incompatible with the planned food deliveries, e.g. celiac disease, gastroparesis, certain food allergies

Following a weight-loss or otherwise restrictive diet

Vigorous exercise >2 hours on >3 days a week

Trial design

Design model

Single group

Treatments tested in this trial

  • Very low carbohydrate diet

    Other intervention

    All meals will be delivered and participants will consume study foods exclusively. Participants will receive a fiber supplement with each meal as needed to promote digestive health, and a daily multi-vitamin, magnesium and omega-3 supplement to ascertain micronutrient sufficiency. Participants will be weighed at each study visit and the diet plan will be adjusted for satiety and weight-maintenance. The diet composition will be as follows: 5% carbohydrate, 75% fat, 20% protein.

Treatment groups

12 Participants
are divided into 1 treatment group
Group A: Very low carbohydrate dietExperimental treatment 1 intervention

Trial outcomes

Primary outcomes

1

Glucagon treatment success, defined as an increase in glucose level to ≥ 70 mg/dL or an Increase of ≥ 20 mg/dL from glucose nadir within 30 minutes after receiving 1 mg glucagon IM

Point-of-care blood glucose levels will be measured pre-dose and every 5 minutes for 30 minutes and until BG is ≥ 70 mg/dL (whichever occurs later), then gradually spaced per MD orders to align with the rest of the labs

Time frame
week 5-12 on the very low carbohydrate diet

Secondary outcomes

1

Recovery from symptoms of hypoglycemia

Recovery from hypoglycemia symptoms will be assessed using a Hypoglycemia Symptoms Scale at baseline, when blood glucose is \< 75 mg/dL, pre-dose, and at 15, 30, 45, 60, 75, and 90 minutes following administration of glucagon. The Hypoglycemia Symptoms Scale measures the intensity of 14 commonly experienced hypoglycemic symptoms on a scale from 0 (not present) to 6 (very intense). The higher the score, the more intense the hypoglycemia symptoms. The sum of each symptom score would yield a range of 0 to 84 (e.g., 14 x 6 = 84). The total score will be calculated as the sum of each symptom score and summarized at each time point.

Time frame
week 5-12 on the very low carbohydrate diet
2

Time to achieve glucagon treatment success

The mean time from glucagon administration to blood glucose ≥ 70 mg/dL or an increase ≥ 20 mg/dL in blood glucose from nadir. Point-of-care blood glucose levels will be measured pre-dose and every 5 minutes for 30 minutes and until BG is ≥ 70 mg/dL (whichever occurs later), then gradually spaced per MD orders to align with the rest of the labs.

Time frame
week 5-12 on the very low carbohydrate diet
3

Plasma levels of beta-hydroxybutyrate following glucagon administration

Levels will be measured at baseline, pre-dose, and at 10, 20, 30, 45, 60, and 90 minutes. Average levels at each time point, peak level, and area under the curve (AUC) will be reported.

Time frame
week 5-12 on the very low carbohydrate diet
4

Plasma levels of free fatty acids following glucagon administration

Levels will be measured at baseline, pre-dose, 10, 20, 30, 45, 60, and 90 minutes. Average levels at each time point, peak level, and area under the curve (AUC) will be reported.

Time frame
week 5-12 on the very low carbohydrate diet

Other outcomes

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