From the breakdown of hydroxykynurenine via kynurenine aminotransferases (KAT) +B6
- Elevated xanthurenic acid has been noted with B6 deficiency.
- Elevated levels have been noted as more significant in oral contraceptive users in studies using a tryptophan load.
- In a mathematical model without a tryptophan load, a moderate vitamin B6 deficiency resulted in a slight increase in xanthurenic acid and a slight decrease in kynurenic acid and anthranilate.
- Without a tryptophan load, urine kynurenine and xanthurenic acid both increase in a pronounced B6 deficiency.
- Animal studies found a low urinary excretion ratio of xanthurenic acid/ kynurenic acid as a possible marker of niacin need, proposing that levels may increase with repletion.
- Niacin (vitamin B3) is a product of tryptophan degradation. In alcoholic pellagra patients, the tryptophanniacin pathway is inhibited after the 3-hydroxyanthranilate oxidase step, which can result in increased kynurenic acid, and decreased xanthurenic acid and quinolinic acid.
Because this pathway is heavily dependent on vitamin B6, elevations of xanthurenic acid can reflect a functional need for vitamin B6.
Kynurenine pathway metabolites may also become elevated when there are needs for vitamin B3.
Elevations in urinary xanthurenic acid are seen with increased intake of tryptophan, and in high estrogen states. Pregnancy and oral contraceptive use is associated with elevated levels of urinary xanthurenic acid where a functional nutrient need for B-vitamins is pronounced.
Abnormalities in the kynurenine pathway have been associated with many clinical conditions including immune suppression, cancer, and inflammatory conditions. Administration of vitamin B6 can decrease xanthurenic acid excretion.
Own it for life
Our exclusive data entry service is a convenient way to get your results into your private dashboard. Simply attach an image or a file of your lab test results, and one of our qualified data entry team members will add the results for you. We support all sorts of files, whether PDFs, JPGs, or Excel. This service is excellent whether you have a lot of reports to upload or are too busy to do the data entry yourself.
We strive to make the data entry process easy for you. Whether by offering dozens of templates to choose from that pre-populate the most popular laboratory panels or by giving you instant feedback on the entered values. Our data entry forms are an easy, fast, and convenient way to enter the reports yourself. There is no limit on how many lab reports you can upload.
billed every month
Data entry included
$6.60/month billed annually
Data entry included
own it for life
Are You a Health Professional?
Get started with our professional plan
Welcome to Healthmatters Pro.
Save time on interpreting lab results with the largest database of biomarkers online. In-depth research on any test at your fingertips, all stored and tracked in one place. Learn more
Pro Monthly Plus
for health professionals
$75 per month