Effects of Different Doses of Pinitol on Carbohydrate Metabolism Parameters in Healthy Subjects

Study Overview
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Brief Summary
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The purpose of this study was to assess the acute effects of increasing doses of pinitol on glucose tolerance and insulin sensitivity and to evaluate the absorption of pinitol after consumption of an oral nutritive pinitol-enriched beverage in healthy subjects.

Official Title
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Effects of Different Doses of Pinitol on Carbohydrate Metabolism Parameters in Healthy Subjects: a Randomized Cross-over Placebo-controlled Study

Conditions
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Healthy, Insulin Sensitivity

Intervention / Treatment
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* Dietary Supplement: Pinitol


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: The inclusion criteria for all subjects were age range of 18-65 years, body mass index of 20-30 Kg/m2 and clinically normal kidney function, liver function, heart function, protein status and haematological profile. Exclusion Criteria: Exclusion criteria were pregnancy or lactation, alteration of carbohydrate metabolism, fasting glycaemia ≥5.55 mmol/l on at least two previous occasions, diabetes, or medication known to interfere with glucose metabolism.

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: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Low dose (2.5 g of pinitol)<br>Each subject completed two 1-day trials separated by a 1-week interval. The subjects were randomized by alternation method to belong to the group of low, intermediate or high dose, containing 2.5, 4.0 or 6.0 g of pinitol, respectively. Each subject was newly randomized (1:1) and cross-over into one of two groups: one that received the pinitol-enriched beverage, and the other a placebo beverage. In this way, each dose and its corresponding placebo were studied in 10 normoglycaemic subjects. | Dietary Supplement: Pinitol<br>* Three doses of Fruit Up® (diluted with mineral water to a final volume of 330 ml) were evaluated, and were equivalent to an intake of 2.5, 4.0 and 6.0 g of pinitol. The placebo beverage contained equal amounts of non-polyol carbohydrates with similar macronutrient composition and energy intake as that those obtained through the pinitol beverage, but excluding pinitol.<br>* Other names: 3-O-methyl-D-chiro-inositol;|
| Experimental: Intermediate dose (4.0 g of pinitol)<br>Each subject completed two 1-day trials separated by a 1-week interval. The subjects were randomized by alternation method to belong to the group of low, intermediate or high dose, containing 2.5, 4.0 or 6.0 g of pinitol, respectively. Each subject was newly randomized (1:1) and cross-over into one of two groups: one that received the pinitol-enriched beverage, and the other a placebo beverage. In this way, each dose and its corresponding placebo were studied in 10 normoglycaemic subjects. | Dietary Supplement: Pinitol<br>* Three doses of Fruit Up® (diluted with mineral water to a final volume of 330 ml) were evaluated, and were equivalent to an intake of 2.5, 4.0 and 6.0 g of pinitol. The placebo beverage contained equal amounts of non-polyol carbohydrates with similar macronutrient composition and energy intake as that those obtained through the pinitol beverage, but excluding pinitol.<br>* Other names: 3-O-methyl-D-chiro-inositol;|
| Experimental: High dose (6.0 g of pinitol)<br>Each subject completed two 1-day trials separated by a 1-week interval. The subjects were randomized by alternation method to belong to the group of low, intermediate or high dose, containing 2.5, 4.0 or 6.0 g of pinitol, respectively. Each subject was newly randomized (1:1) and cross-over into one of two groups: one that received the pinitol-enriched beverage, and the other a placebo beverage. In this way, each dose and its corresponding placebo were studied in 10 normoglycaemic subjects. | Dietary Supplement: Pinitol<br>* Three doses of Fruit Up® (diluted with mineral water to a final volume of 330 ml) were evaluated, and were equivalent to an intake of 2.5, 4.0 and 6.0 g of pinitol. The placebo beverage contained equal amounts of non-polyol carbohydrates with similar macronutrient composition and energy intake as that those obtained through the pinitol beverage, but excluding pinitol.<br>* Other names: 3-O-methyl-D-chiro-inositol;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Dose-response curves to assess the change in glucose and insulin concentration after an oral ingestion of different doses of pinitol with respect to the corresponding placebo | Each subject attended the Endocrinology Service in the morning after 12-hour overnight fasting. Blood sample was collected in vacutainer serum separator tubes at baseline (minute 0; while still fasting), 15, 30, 45, 60, 90 and 120 minutes after consumption of the tested product placebo or pinitol-enriched beverage. Glucose concentrations were measured by means of enzymatic assay in an autoanalyzer. Insulin concentrations were determined by enzyme-linked immunosorbent assay. | up to 120 minutes | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Dose-response curves to assess the change in pinitol concentration after an oral ingestion of different doses of pinitol with respect to the corresponding placebo | Plasma pinitol analysis blood samples were collected into vacutainers containing lithium heparin at baseline, 60, 120, 180 and 240 minutes after consumption of the tested product placebo or pinitol-enriched beverage. Pinitol concentration was determined by gas chromatography/ mass spectrometry | up to 240 minutes | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Glucose, Insulin, 3-O-methyl-D-chiro-inositol