Effects of a Bakery Product Enriched With Fibre and L-carnitine on Insulin Resistance in Patients With Metabolic Syndrome

Study Overview
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Brief Summary
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The aim of this study was to evaluate the efficacy of a bakery product enriched with dietary fibre and L-carnitine on glucose homeostasis and insulin sensitivity in overweight patients with or without metabolic syndrome.

Detailed Description
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Conceivably, different biochemical changes in insulin-mediated signalling pathways may contribute to an impaired insulin-mediated glucose transport and metabolism that eventually results in insulin resistance and the clinical features of metabolic syndrome. According to this, both compounds -L-carnitine and dietary fiber- interacting by different mechanism of action could improve glucose homeostasis and insulin sensitivity. However, the health beneficial effects of the combination of both compounds are not shown and confirmation of the functionality of such products must be accomplished by conducting the appropriate studies intervention nutrition.

Official Title
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Evaluation of a Bakery Product Enriched With Fibre and L-carnitine on Cardiovascular Risk Parameters in Patients With Metabolic Syndrome: a Randomized, Double-blind, Placebo-controlled Study

Conditions
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Metabolic X Syndrome, Overweight, Dyslipidemias

Intervention / Treatment
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* Dietary Supplement: dietary fibre plus L-carnitine bread
* Dietary Supplement: Placebo bread


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: BMI between 25 and 35 Kg/m2 Exclusion Criteria: Pregnancy or lactation Kidney, liver and thyroid disease History of cardiovascular or chronic inflammatory disease Diabetes mellitus Lipid-lowering medication Triglyceride concentration > 400 mg/dl Consumption of other carnitine and/or fibre-enriched foods

Ages Eligible for Study
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Minimum Age: 25 Years
Maximum Age: 70 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: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: With metabolic syndrome<br>Before dietary therapy was initiated, in order to stabilise dietary patterns prior to intervention, patients were submitted to a 4-weeks run-in period of a caloric restriction of 500 Kcal to their usual diet. After this adaptation period, two intervention groups were evaluated: a calorie-restricted diet plus bread-enriched product that received 15.08 g of dietary fibre (9.49 g of insoluble fibre and 5.59 g of soluble fibre) plus 2325 mg of L-carnitine/day in 130 g of bread (enriched group) and a calorie-restricted diet plus placebo bread group whose diet included 130 g/day of not-enriched bread (placebo group). | Dietary Supplement: dietary fibre plus L-carnitine bread<br>* The enriched bread consisted of a mix of wheat flour, vegetable flour, rye flour, wheat gluten, soy protein, soluble and insoluble dietary fibre, inulin, guar gum, L-carnitine salt, diacetyl tartaric, enzymes, ascorbic acid, water and yeast. Patients were recommended to consume the bread twice per day with main meals.<br>Dietary Supplement: Placebo bread<br>* The placebo group received commercially available bread with a similar macronutrient composition and energy intake to that consumed by the enriched bread group but without L-carnitine and dietary fibre. Patients were recommended to consume the bread twice per day with main meals.<br>|
| Experimental: Without metabolic syndrome<br>Before dietary therapy was initiated, in order to stabilise dietary patterns prior to intervention, patients were submitted to a 4-weeks run-in period of a caloric restriction of 500 Kcal to their usual diet. After this adaptation period, two intervention groups were evaluated: a calorie-restricted diet plus bread-enriched product that received 15.08 g of dietary fibre (9.49 g of insoluble fibre and 5.59 g of soluble fibre) plus 2325 mg of L-carnitine/day in 130 g of bread (enriched group) and a calorie-restricted diet plus placebo bread group whose diet included 130 g/day of not-enriched bread (placebo group). | Dietary Supplement: dietary fibre plus L-carnitine bread<br>* The enriched bread consisted of a mix of wheat flour, vegetable flour, rye flour, wheat gluten, soy protein, soluble and insoluble dietary fibre, inulin, guar gum, L-carnitine salt, diacetyl tartaric, enzymes, ascorbic acid, water and yeast. Patients were recommended to consume the bread twice per day with main meals.<br>Dietary Supplement: Placebo bread<br>* The placebo group received commercially available bread with a similar macronutrient composition and energy intake to that consumed by the enriched bread group but without L-carnitine and dietary fibre. Patients were recommended to consume the bread twice per day with main meals.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| To assess changes in hydrocarbonated metabolism parameters before and after fibre+carnitine/placebo administration | Blood samples were collected in vacutainer serum separator tubes, after 12-hour overnight fasting, to analyze glucose, insulin and C-peptide concentration at baseline (after a four weeks run-in period of a healthy diet), and 12 weeks after fibre+carnitine/placebo administration. Glucose was determined using enzymatic techniques and insulin and C-peptide were measured by an enzymatic luminescence technique in an autoanalyzer. Insulin resistance was calculated by homeostasis model assessment (HOMA = (fasting insulin (μU/mL×) fasting glucose (mg/dl)/405). | baseline and 12 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| To evaluate changes in lipid parameters before and after fibre+carnitine/placebo administration | Blood samples were collected in vacutainer serum separator tubes, after 12-hour overnight fasting, to analyze lipid profile at baseline (after a four weeks run-in period of a healthy diet), and 12 weeks after fibre+carnitine/placebo administration. Total cholesterol and triglycerides were measured by means of enzymatic assays, and high-density lipoproteins (HDL) concentrations were recorded with an autoanalyzer using a direct method. Low-density lipoprotein (LDL) concentration was calculated using the method of Friedewald. Non-HDL concentration was obtained by calculating the difference between total cholesterol and HDL. LDL subfractions were separated by high-resolution polyacrylamide gel tubes. The LDL electrophoretic profile allows 2 patterns to be defined: pattern A or large and buoyant LDL, and pattern non-A or small and dense LDL. | baseline and 12 weeks | 
| To evaluate changes in a composite measure of inflammatory parameters before and after fibre+carnitine/placebo administration | Blood samples were collected in vacutainer serum separator tubes, after 12-hour overnight fasting, to analyze inflammatory markers at baseline (after a four weeks run-in period of a healthy diet), and 12 weeks after fibre+carnitine/placebo administration. Levels of high-sensitive C-reactive protein (hsCRP) and proinflammatory cytokines interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were analysed using a flow analyser system | baseline and 12 weeks | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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L-carnitine, fibre, bakery product, insulin resistance