To investigate whether changes in fructose dietary intake can help to improve dietary fructose-induced insulin resistance and post bariatric weight loss in obese subjects of Caucasian descent
In this Randomized controlled trial, males and premenopausal women, scheduled for RYGB bariatric surgery at Spaarne Gasthuis of Caucasian Dutch descent, age ≥18 years will be put on either their high fructose diet (\>100 gram fructose / day) versus a low fructose diet (\<30 gram fructose intake per day isocaloric correction with dextrose) 4 weeks before bariatric surgery. For both groups, an oral (13-C labeled) fructose challenge will be performed at baseline as well as 4 weeks after start of the diet (in the week of the surgery). Outcome measures: Primary endpoints are changes in oral fructose induced glucose and insulin postprandial plasma excursions (measured by a fructose tolerance test with 120mg 13C6-labeled fructose in relation to long term glucose handling (HOMA and Freestyle Libre) at baseline and after 4 weeks (in the week of surgery) after both diets. Secondary endpoints are changes in histology and RNA seq gene expression in liver, adipose and jejunum tissue harvested with biopsy during bariatric surgery and changes in fecal gut microbiota composition, 24h feces and urine for fructose content and (postprandial) plasma metabolites including endogenous ethanol at both timepoints. Of note, dietary intake including fructose content will be monitored by an experienced dietician from Spaarne Gasthuis. Finally, to study relations with (long term) weight loss up to 1 year after surgery related to dietary intake, the last time points at 6 and 12 months after surgery (during regular clinical outpatient visits) will be used as an exploratory endpoint to gain more insight into the relationship between gut microbiota, (pre surgery) dietary fructose intake and weight loss after bariatric surgery.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
DOUBLE
Enrollment
20
oral ingestion of fructose vs dextrose
Amsterdam UMC location AMC
Amsterdam, Netherlands
RECRUITINGoral fructose handling
to correlate changes in oral fructose excursions (measured by AUC of fructose tolerance test enriched with 13C6-labeled fructose with glucose excursions (MAGE by Freestyle Libre)
Time frame: 4 weeks
fructose changes in visceral organs
to correlate with changes in histology and RNA seq gene expression in liver, adipose and jejunum tissue harvested with biopsy during bariatric surgery
Time frame: 4 weeks up to one year
gutmicrobiota
to correlate with changes in fecal gut microbiota composition
Time frame: 4 weeks up to one year
metabolites
to correlate with (postprandial) plasma metabolites including endogenous ethanol
Time frame: 4 weeks up to one year
weight
to correlate with with (long term) weight loss at 6 and 12 months after surgery
Time frame: 4 weeks up to one year
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