Effect of a Carbohydrate-rich Diet in Healthy Subjects

Université de Sherbrooke14 enrolled

Overview

The present research protocol will analyze whether a short-term modification (one week) of dietary habits would have an impact on the postprandial metabolism of dietary fatty acids and on their uptake by non-adipose tissues, in healthy subjects. Each subject will participate in two protocols randomly determined and separated by a period of one month: a 7-day isocaloric diet (Protocol A) and a 7-day carbohydrate-rich diet containing +50% of the subject's energy needs. (Protocol B). At the end of each diet, the subject will go through a postprandial metabolic study of 8 hours where different parameters will be measured thanks to PET imaging and perfusions of stables isotopes.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Enrollment

Conditions

Lipid Metabolism Disorder

Interventions

isocaloric diet

Eligibility

Sex: ALLMin age: 18 YearsMax age: 65 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: Healthy subjects: subjects with normal glucose tolerance determined according to an oral glucose tolerance test and with a BMI above 25 kg/m2 without first degree of familial history of type 2 diabetes (parents, siblings). Exclusion Criteria: * overt cardiovascular disease as assessed by medical history, physical exam, and abnormal ECG * treatment with a fibrate, thiazolidinedione, beta-blocker or other drug known to affect lipid or carbohydrate metabolism (except statins, metformin, and other antihypertensive agents that can be safely interrupted) * presence of liver or renal disease, uncontrolled thyroid disorder, previous pancreatitis, bleeding disorder, or other major illness * smoking (\>1 cigarette/day) and/or consumption of \>2 alcoholic beverages per day * prior history or current fasting plasma cholesterol level \> 7 mmol/l or fasting TG \> 5 mmol/l * any other contraindication to temporarily interrupt current meds for lipids or hypertension * being pregnant * not be barren

Outcomes

Primary Outcomes

whole-body organ-specific Dietary Fatty Acid (DFA) partitioning

will be determined by whole-body CT (16 mA) followed by PET acquisition of 18FTHA

Time frame: 2 months

Left ventricular function by Positron Emiting Positron (PET) ventriculography

will be determined using 11C-acetate PET/CT. 180 MBq will be administered by bolus injection at fasting. After a transmission scan and regional CT (40mA), a 30-min dynamic list-mode PET acquisition will be performed on a 18 cm-high thoraco-abdominal segment to include the left cardiac ventricle and most of the liver on a Philips Gemini TOF PET/CT

Time frame: 2 months

Secondary Outcomes

Cardiac DFA uptake

will be assessed using PET/CT method with oral administration of 18FTHA followed by a 30 min. dynamic PET acquisition

Time frame: 2 months

Cardiac and hepatic oxidative metabolism index

will be determined using 11C-acetate PET/CT followed by a 30 minutes dynamic PET acquisition.

Time frame: 2 months

Cardiac and hepatic blood flow

will be determined using 11C-acetate PET/CT followed by a 30 minutes dynamic PET acquisition..

Time frame: 2 months

metabolites appearance rate

will be determined by perfusion of stable isotope tracers

Time frame: 6 months

energy metabolism (whole body production)

by indirect calorimetry

Time frame: 4 months

hormonal responses

analysed by colorimetric and Elisa tests

Time frame: 4 months

Insulin sensitivity

will be determined using the HOMA-IR (based on fasting insulin and glucose) levels

Time frame: 4 months

Insulin secretion rate

will be assessed using deconvolution of plasma C-peptide with standard Cpeptide kinetic parameters

Time frame: 4 months

β-cell function

will be assessed by calculation of the disposition index (DI) that is insulin secretion in response to the ambient insulin

Time frame: 4 months

Anthropometric parameters

will be measured at each postprandial metabolic study

Time frame: 2 months

Effect of a Carbohydrate-rich Diet in Healthy Subjects

Overview

Conditions

Interventions

Eligibility

Locations (1)

Outcomes

Primary Outcomes

Secondary Outcomes