Intestinal β-carotene bioconversion in humans is determined by a new single-sample, plasma isotope ratio method and compared with traditional and modified area-under-the-curve methods.

The vitamin A value (bioefficacy) of provitamin A carotenoids is determined by absorption of the carotenoid (bioavailability) and its subsequent conversion to retinol (bioconversion). Here we show that a single plasma sample collected 6 h after ingesting a test dose of stable isotope-labeled β-carotene can estimate intestinal bioconversion of β-carotene… (More)