Detection of Salivary Insulin Following Meals

Study Overview
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Brief Summary
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In addition to its role as the major regulator of glucose uptake into peripheral tissues, the hormone insulin is also a primary regulator of fat storage and fat burning of the body. Mechanistic animal studies have shown that high insulin may be the initial trigger for weight gain and be the proximal cause of obesity. There is currently no quick or non-invasive way of measuring insulin as research and clinical techniques require collection of a blood sample followed by a complicated and costly biochemical assay. The investigators will test the hypothesis that insulin levels can be accurately measured in saliva in humans following meals that elicit high and low blood insulin responses. Findings will help determine if insulin can be use as a valid fluid to track insulin changes in humans.

Detailed Description
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Lean and obese healthy participants will consume both a high carbohydrate meal and a low carbohydrate meal designed to elicit different insulin responses on two separate occasions. Blood samples and saliva samples will be collected for 2 hours following each meal and insulin will be measured in both plasma and saliva. The relationship between plasma and saliva insulin following the two meals will be assessed.

Official Title
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Detection of Salivary Insulin Following Low Versus High Carbohydrate Meals in Humans

Conditions
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Insulin Resistance

Intervention / Treatment
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* Behavioral: High-carbohydrate meal
* Behavioral: Low-carbohydrate meal


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Body mass index between 18.5-24.9 or over 30.0 kg/m2 Exclusion Criteria: Diabetes or other medical conditions affecting glucose or insulin levels Smoker Competitive athlete Vegan or vegetarian

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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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: High-carbohydrate meal<br>High carbohydrate breakfast meal consisting of oatmeal and berries. | Behavioral: High-carbohydrate meal<br>* Participants will consume a high-carbohydrate low fat meal. The macronutrients content will be 55% carbohydrate, 25% protein and 20% fat providing 400-500 kcal. Between interventions there will be at least a 48-hours washout, where participants are encouraged to return to their baseline dietary habits.<br>|
| Experimental: Low-carbohydrate meal<br>Low carbohydrate breakfast meal consisting of eggs and avocado. | Behavioral: Low-carbohydrate meal<br>* Participants will consume a low-carbohydrate high fat meal. The macronutrients content will be 10% carbohydrate, 25% protein and 65% fat and will provide 400-500 kcal (matched to the high carbohydrate meal). Between interventions there will be at least a 48-hours washout, where participants are encouraged to return to their baseline dietary habits.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Peak plasma insulin level | Peak plasma insulin concentration in high carbohydrate versus low carbohydrate arm. | 0-120 minutes | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Plasma insulin area under the curve | Area under the curve for plasma insulin in high carbohydrate versus low carbohydrate arm. | 0-120 minutes | 
| Relationship between peak saliva and peak plasma insulin | Correlation of peak plasma and peak saliva insulin in high carbohydrate versus low carbohydrate arm. | 0-120 minutes | 
| Timing of peak saliva and peak plasma insulin | Timing of peak plasma and peak saliva insulin in high carbohydrate versus low carbohydrate arm. | 0-120 minutes | 
| Relationship between saliva insulin area under the curve and plasma insulin area under the curve | Correlation between area under the curve for plasma and saliva insulin in high carbohydrate versus low carbohydrate arm. | 0-120 minutes | 
| Peak saliva insulin level | Peak salivary insulin in high carbohydrate versus low carbohydrate arm | 0-120 minutes | 
| Saliva insulin area under the curve | Area under the curve for salivary insulin in high carbohydrate versus low carbohydrate arm | 0-120 minutes |