A simple method for measuring zinc absorption in man using a short-lived isotope (69mZn)

Area of Science:

• Biochemistry and Nutritional Science
• Medical Diagnostics

Background:

• Accurate assessment of zinc absorption is crucial for diagnosing deficiencies and monitoring treatment.
• Existing methods for measuring zinc absorption can be complex or involve prolonged radiation exposure.

Purpose of the Study:

• To develop and validate a simple, safe, and effective test for measuring oral zinc absorption.
• To assess the impact of food intake on zinc absorption kinetics.

Main Methods:

• A short-lived zinc isotope (69mZn) was administered orally with elemental zinc.
• Plasma radioactivity was measured over 8 hours to create an appearance curve.
• An intravenous dose of the isotope was given later to construct a disappearance curve, with absorption calculated via computer analysis (deconvolution).

Main Results:

• Mean oral zinc absorption in five normal subjects was 61% (range 41-79%).
• Concurrent food intake significantly delayed and reduced zinc absorption to less than 20% by 8 hours.
• The use of a short half-life isotope minimizes patient radiation exposure.

Conclusions:

• The developed 69mZn isotope test provides a simple and reliable method for assessing zinc absorption.
• This method offers a low-radiation alternative for clinical use.
• Food consumption significantly impairs oral zinc absorption, highlighting the importance of timing for accurate testing.