A high fructose diet increases fasting and post-prandial triglyceride (TG) concentrations in sedentary healthy human subjects.These effects may be secondary to fructose-induced hepatic de novo lipogenesis. Recent evidence indicate that exercise can prevent fructose induced dyslipidemia.This study will evaluate 1. how exercise effects the metabolic fate of oral fructose 1a) when exercise is performed before fructose ingestion 1b) when exercise is performed after fructose ingestion Metabolic effects of exercise will be assessed in healthy male subjects by measuring fructose oxidation (13CO2 production), fructose conversion into glucose (13C glucose concentrations in blood) and hepatic fructose conversion into lipid (13C palmitate-very low density lipoprotein (VLDL) concentrations in blood) after ingestion of 13C-labelled fructose meals 2. how fructose and protein modulate muscle glycogen and intramyocellular lipid repletion after exercise Healthy male subjects will be fed various fructose, glucose, lipid and whey protein meals after a glycogen/intramyocellular lipid depleting exercise. The effects of meals' composition will be assessed after 24 hours by measuring intramyocellular lipids and glycogen using proton-magnetic resonance spectroscopy (MRS).
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
NONE
Enrollment
8
cycling at 100W during 60 min
isocaloric nutrition with fructose, cream and whey protein during the 24 hour following a glycogen/intramyocellular lipid depleting exercise
isocaloric nutrition with glucose, cream and whey protein during the 24 hour following a glycogen/intramyocellular lipid depleting exercise
Centre Hospitalier Universitaire Vaudois
Lausanne, Canton of Vaud, Switzerland
Plasma triglyceride
measurement of total and VLDL-TG concentrations in study 1
Time frame: measurements in fasting conditions and every hour from 7:00 am to 4:00 pm (up to 9 hours)
intramyocellular lipids
Measurement by 1H-MRS in muscle vastus lateralis in study 2
Time frame: after glycogen/intramyocellular lipid depleting exercise and after 24 hour controlled feeding post exercise
Fructose conversion into lipids
Estimated from 13C palmitate-VLDL concentration
Time frame: measured from 7:00 am to 4:00 pm in study 1 (up to 9 hours)
Fructose conversion into glucose
measurements obtained from plasma 13C glucose concentrations and whole body glucose production measured by 6,6 d2 glucose in study 1)
Time frame: measured between 7:00 am and 4:oo pm (up to 9 hours)
intramyocellular glycogen concentrations
Measured by 1H-MRS in muscle vastus lateralis in study 2
Time frame: after glycogen/intramyocellular lipid depleting exercise and after 24 hour controlled feeding post exercise
fructose oxidation
Calculated from breath 13CO2 production
Time frame: measured from 7:00 am to 4:00 pm in study 1 (up to 9 hours)
exogenous lipid oxidation
Lipids ingested will be labeled with 13C-triolein, and exogenous lipid oxidation will be measured from breath 13CO2 production
Time frame: measured from 7:00 am to 4:00 pm in study 2 (up to 9 hours)
This platform is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.