NCT02135393

Where is the Initial Site of Biotransformation of Folates in Humans?

Folic Acid Handling by the Human Gut: Implications for Food Fortification and Supplementation

• Status: Completed
• Phase: N/A
• Study type: Interventional
• Enrollment: 6 (actual)
• Sponsor: Newcastle-upon-Tyne Hospitals NHS Trust · Academic / Other
• Sex: All
• Age: —
• Healthy volunteers: Accepted

Summary

The aim of this study is to test the assumption that, in humans, folic acid, a dietary supplement is biotransformed (reduced and methylated) to the natural circulating plasma folate 6S-5Methyltetrahydrofolic acid (5-MTHF) in the intestinal mucosa.

Detailed description

Current thinking, based mainly on rodent studies, is that physiological doses of folic acid (pteroylmonoglutamic acid), like dietary vitamin folates, are biotransformed in the intestinal mucosa and transferred to the portal vein as the natural circulating plasma folate, 5-methyltetrahydrofolic acid (5-MTHF), before entering the liver and the wider systemic blood supply. Study design:Open labelled study that samples portal and peripheral veins for labelled folate concentrations following oral ingestion with physiological doses of dietary supplements stable-isotope-labelled folic acid, or, the reduced folate, 5-formyltetrahydrofolic acid (5-FormylTHF). The study was performed in subjects with a Transjugular Intrahepatic Porto Systemic Shunt (TIPSS) in situ at the time of a routine annual patency check to allow blood samples to be taken from the portal vein. The aim of this study is to test the assumption that, in humans, folic acid is biotransformed (reduced and methylated) to 5-MTHF in the intestinal mucosa.

Conditions

• Healthy

Interventions

Type	Name	Description
DIETARY_SUPPLEMENT	13C5-folic acid or 13C5-6S-5-FormylTHF	Subjects with an insitu transjugular intrahepatic porto systemic stent shunt assigned to receive either a physiological 500 nmol (220 µg folic acid equivalent) dose of 13C5-folic acid or 13C5-6S-5-FormylTHF at the time of routine shunt venography to check patency followed by portal venous sampling at pre defined time points for 85 minutes and then given 13C5-6S-5-FormylTHF ator 13C5-folic acid at their next annual venography patency check with portal venous sampling at pre defined time points for 85 minutes

Timeline

• Start date: 2009-04-01
• Primary completion: 2011-09-01
• Completion: 2011-09-01
• First posted: 2014-05-09
• Last updated: 2014-05-09

Locations

2 sites across 1 country: United Kingdom