Meal Testing for Healthy Subjects

Recruiting at 1 trial location

Overseen By Susanne M Votruba, Ph.D.

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

Must not be taking: Metabolism-altering drugs

Disqualifiers: Diabetes, Anemia, Pregnancy, Alcohol abuse, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: 4

Duration: 8 weeks

79 Participants Needed

What You Need to Know Before You Apply

What is the purpose of this trial?

Background: Researchers use mixed meal tolerance tests (MMTTs) to look at how people s bodies respond to eating a meal. However, researchers do not agree on how to decide the number of calories to give in each meal. Some use fixed meals, which are the same size for everyone, and some use adjusted meals, based on the size of the person s body. Researchers want to know which MMTT is best to use for future research. Objective: To learn how fixed vs adjusted meals affect blood glucose levels in healthy people. Eligibility: Healthy people aged 18 years or older. Design: Participants will have 3 or 4 clinic visits of up to 8 hours in 8 weeks. Participants will have baseline tests: Their height, weight, and waist size will be measured. They will have an oral glucose tolerance test: A needle attached to a tube (IV) will be inserted into a vein in the arm. They will have a sugary drink. Blood samples will be taken from the tube at intervals up to 3 hours after the drink. They will have a body scan. Participants will have 2 MMTT visits. One will include a fixed meal and one will include an adjusted meal. They will have tests at both visits: Resting metabolic rate: A clear hood will be placed over the participant s head while they rest for 20 minutes. This will measure the oxygen they breathe in and out. MMTT. Participants will have 5 minutes to drink a liquid meal. Blood samples will be taken at intervals for the next 4 hours....

Will I have to stop taking my current medications?

Yes, if you are currently using medications, dietary supplements, or alternative therapies that alter energy metabolism, you will not be eligible to participate in this study.

Is the mixed meal tolerance test safe for humans?

The mixed meal tolerance test (MMTT) has been used in various studies involving healthy individuals and patients with different types of diabetes, and no safety concerns have been reported in these contexts. ^{1 2 3 4 5}

How does the meal testing treatment differ from other treatments for healthy subjects?

Meal testing for healthy subjects is unique because it uses a standardized meal to assess metabolic responses, providing a more clinically relevant picture of metabolic status compared to traditional glucose tolerance tests. This approach is less about treating a condition and more about understanding how the body processes food in a natural setting. ^{1 3 4 6 7}

What data supports the effectiveness of the treatment Adjusted Mixed Meal Test?

Research shows that mixed meal tolerance tests (MMTTs) are reliable for assessing how the body handles sugar and insulin, which is important for understanding conditions like type 2 diabetes. These tests help measure how well the body's beta cells (cells in the pancreas that produce insulin) are working, which can be useful in managing diabetes. ^{1 3 4 5 8}

Who Is on the Research Team?

Susanne M Votruba, Ph.D.

Principal Investigator

National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

Are You a Good Fit for This Trial?

This trial is for healthy adults over 18 years old. It's designed to see how different calorie amounts in meals affect blood sugar levels. Participants will need to visit the clinic several times and undergo various tests, including drinking a sugary solution and having their metabolic rate measured.

Inclusion Criteria

Provision of signed and dated informed consent form

Agreement to adhere to Lifestyle Considerations throughout study duration

Healthy, as determined by medical history, physical examination, and laboratory tests

Exclusion Criteria

Current pregnancy, pregnancy within the past 6 months or currently lactating

Fasting plasma glucose >= 126 mg/dL

Conditions not specifically mentioned above may serve as criteria for exclusion at the discretion of the investigators

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

1 visit (in-person)

Baseline Testing

Participants undergo baseline tests including height, weight, waist size measurements, an oral glucose tolerance test, and a body scan

1 day

1 visit (in-person)

Treatment

Participants undergo 2 Mixed Meal Tolerance Test (MMTT) visits, one with a fixed meal and one with an adjusted meal, including metabolic rate testing and blood sampling

8 weeks

2-3 visits (in-person)

Follow-up

Participants are monitored for safety and effectiveness after treatment

4 weeks

What Are the Treatments Tested in This Trial?

Interventions

• Adjusted Mixed Meal Test
• Fixed Mixed Meal Test

Trial Overview Researchers are testing two types of mixed meal tolerance tests (MMTTs): one with a fixed caloric dose for everyone, and another adjusted based on individual body size. The goal is to determine which method provides more accurate results for future studies.

How Is the Trial Designed?

Group I: 2 Active Control 1 Intervention

Adjusted Mixed Meal Test

Group II: 1 Active Control 1 Intervention

Fixed Mixed Meal Test

Who Is Running the Clinical Trial?

National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

Lead Sponsor

Trials

2,513

Recruited

4,366,000+

Published Research Related to This Trial

The study demonstrated that mixed meal tolerance tests (MMTTs) are reliable for estimating beta-cell function in individuals with type 2 diabetes, showing significantly lower intra-individual variation compared to inter-individual variation in C-peptide, insulin, and glucose responses.

Different macronutrient compositions in liquid meals (specifically varying protein and carbohydrate levels) did not lead to significant changes in C-peptide and insulin responses, indicating that moderate dietary differences may not impact beta-cell function assessments.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Impact of mixed meal tolerance test composition on measures of beta-cell function in type 2 diabetes. Kössler, T., Bobrov, P., Strassburger, K., et al.[2021]

In a study of 894 individuals undergoing mixed-meal tolerance tests (MMTTs), the reproducibility of glucose responses was found to be moderate for breakfast but poor for lunch, indicating variability in how individuals respond to meals based on timing and glucose regulation status.

For those with type 2 diabetes (T2D), the reproducibility of glucose responses was high, suggesting that MMTTs may be more consistent in this group, while insulin responses showed lower reproducibility, highlighting the complexity of insulin dynamics in different glucose regulation states.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Reproducibility and determinants of the metabolic responses during a mixed-meal tolerance test. Stinson, EJ., Piaggi, P., Mitchell, CM., et al.[2023]

Mixed-meal tolerance tests were conducted on healthy controls, type 1A diabetes patients, and fulminant type 1 diabetic patients to assess their metabolic responses after an overnight fast.

The study provides insights into how different types of diabetes affect the body's ability to process mixed meals, highlighting potential differences in metabolic function among these groups.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

"Preserved" glucagon secretion in fulminant type 1 diabetes. Murase-Mishiba, Y., Bessho-Tachibana, M., Imagawa, A.[2020]

A fixed combination of 10 mg mitiglinide and 0.2 mg voglibose significantly reduced postprandial hyperglycemia in type 2 diabetes patients after breakfast, lunch, and dinner, indicating its efficacy in managing blood sugar levels throughout the day.

The treatment improved metabolic responses by increasing insulin and C-peptide levels while decreasing free fatty acids and triglycerides, confirming its beneficial effects on glycemic control in T2DM patients.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

The glycemic/metabolic responses to meal tolerance tests at breakfast, lunch and dinner, and effects of the mitiglinide/voglibose fixed-dose combination on postprandial profiles in Japanese patients with type 2 diabetes mellitus. Ono, Y., Nakamura, A., Cho, KY., et al.[2019]

In a study involving six individuals who underwent weight loss interventions, the liquid-mixed meal was found to be the most tolerable, with a 99% completion rate, compared to solid-mixed and high-fat meals.

The liquid-mixed meal also induced significantly higher levels of incretin hormones and insulin secretion, making it the preferred choice for evaluating glucose metabolism in post-weight loss patients.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Effects of meal composition on postprandial incretin, glucose and insulin responses after surgical and medical weight loss. Lee, CJ., Brown, TT., Cheskin, LJ., et al.[2021]

In a study of 41 patients with monogenic diabetes, the mixed meal tolerance test (MMTT) effectively assessed beta-cell function, revealing that patients with GCK mutations had significantly better beta-cell responses compared to those with HNF4A and KCNJ11 mutations.

The study identified a baseline C-peptide level of 133.5 pmol/L as a predictive marker for successfully switching patients to oral sulfonylurea treatment, suggesting that MMTT can guide treatment decisions after molecular diagnosis.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Kinetics of C-peptide during mixed meal test and its value for treatment optimization in monogenic diabetes patients. Stankute, I., Verkauskiene, R., Dobrovolskiene, R., et al.[2021]

In a study involving 91 adults with insulin-treated diabetes, it was found that omitting insulin during the mixed meal tolerance test may not be necessary, as the results were highly correlated whether insulin was included or not (r = 0.98).

Fasting serum C-peptide levels were also shown to be a practical alternative for assessing endogenous insulin secretion, with a cut-off of ≥ 0.07 nmol/l providing 100% sensitivity and 97% specificity for significant insulin secretion.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

The impact of insulin administration during the mixed meal tolerance test. Besser, RE., Jones, AG., McDonald, TJ., et al.[2022]

A standardized meal test produces a more consistent plasma glucose and insulin response compared to the traditional glucose tolerance test, indicating it may better reflect real-life metabolic status.

The glucose tolerance test is primarily useful for diagnosing glucose intolerance, but the standardized meal test shows that carbohydrate tolerance can decrease throughout the day, highlighting the importance of testing conditions.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Comparison of the metabolic response to a glucose tolerance test and a standardized test meal and the response to serial test meals in normal healthy subjects. Owens, DR., Wragg, KG., Briggs, PI., et al.[2019]

Citations

1. England pubmed.ncbi.nlm.nih.gov

Impact of mixed meal tolerance test composition on measures of beta-cell function in type 2 diabetes. [2021]

2. United States pubmed.ncbi.nlm.nih.gov

Reproducibility and determinants of the metabolic responses during a mixed-meal tolerance test. [2023]

3. Japan pubmed.ncbi.nlm.nih.gov

"Preserved" glucagon secretion in fulminant type 1 diabetes. [2020]

4. England pubmed.ncbi.nlm.nih.gov

The glycemic/metabolic responses to meal tolerance tests at breakfast, lunch and dinner, and effects of the mitiglinide/voglibose fixed-dose combination on postprandial profiles in Japanese patients with type 2 diabetes mellitus. [2019]

5. United States pubmed.ncbi.nlm.nih.gov

Effects of meal composition on postprandial incretin, glucose and insulin responses after surgical and medical weight loss. [2021]

6. Ireland pubmed.ncbi.nlm.nih.gov

Kinetics of C-peptide during mixed meal test and its value for treatment optimization in monogenic diabetes patients. [2021]

7. England pubmed.ncbi.nlm.nih.gov

The impact of insulin administration during the mixed meal tolerance test. [2022]

8. United States pubmed.ncbi.nlm.nih.gov

Comparison of the metabolic response to a glucose tolerance test and a standardized test meal and the response to serial test meals in normal healthy subjects. [2019]