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ARS Home » Northeast Area » Boston, Massachusetts » Jean Mayer Human Nutrition Research Center On Aging » Research » Publications at this Location » Publication #136982
Title: QUANTITATIVE ASSESSMENT OF TOTAL-BODY STORES OF VITAMIN A IN ADULTS BY A THREE-DAY DEUTERATED-RETINOL-DILUTION (3D-DRD) PROCEDURE

Author
item RIBAYA-MERCADO, JUDY - HNRCA
item SOLON, FLORENTINO - NUTR CTR OF THE PHILLIPIN
item DALLAL, GERARD - HNRCA
item SOLOMONS, NOEL - CESSIAM
item FERMIN, LIZA - NUTR CTR OF THE PHILLIPIN
item MAZARIEGOS, MANOLO - CESSIAM
item DOLNIKOWSKI, GREGORY - HNRCA
item RUSSELL, ROBERT - HNRCA

Submitted to: The American Journal of Clinical Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/16/2002
Publication Date: 3/1/2003
Citation: RIBAYA-MERCADO, J.D., SOLON, F.S., DALLAL, G.E., SOLOMONS, N.W., FERMIN, L.S., MAZARIEGOS, M., DOLNIKOWSKI, G.G., RUSSELL, R.M. QUANTITATIVE ASSESSMENT OF TOTAL-BODY STORES OF VITAMIN A IN ADULTS BY A THREE-DAY DEUTERATED-RETINOL-DILUTION (3D-DRD) PROCEDURE. AMERICAN JOURNAL OF CLINICAL NUTRITION. 2003. 77:694-9.

Interpretive Summary: We developed a new mathematical formula for predicting total-body stores of vitamin A in adults using a method that involves a much shorter procedure time than the conventional deuterated-retinol-dilution (DRD) procedure (3 days, instead of 3 weeks). Up to now, the DRD is the only method of assessing vitamin A status that gives a quantitative estimate of the body's total stores of vitamin A. It involves ingesting an oral dose of a stable isotope of vitamin A called deuterium-labeled vitamin A, and waiting ~ 3 weeks for the labeled vitamin A to equilibrate (or reach a plateau) with non-labeled vitamin A in the blood before taking a blood sample for analyses of labeled and non-labeled vitamin A compounds. The new procedure does not require equilibration of the test dose of vitamin A isotope in blood, thus blood samples can be drawn at 3 days, hence we are calling the new procedure: 3-day deuterated-retinol-dilution (3d-DRD). The predictive equation for total-body stores of vitamin A using 3d-DRD was derived by giving an oral dose of vitamin A isotope to subjects; taking a blood draw 3 days and 20 days later; analyzing serum for the ratio of labeled to non-labeled vitamin A. The higher the ratio, the poorer the vitamin A status since there is less non-labeled vitamin A in the body to dilute the administered labeled dose. The ratio for 20-day serum samples were used in a conventional mathematical formula for obtaining estimates of the total-body stores of vitamin A. Since the calculated estimates of body stores correlated with the vitamin A isotope ratios at 3 days after dosing with labeled vitamin A, we were able to arrive at a predictive equation for total-body stores of vitamin A using 3-day data and conclude that a 3d-DRD equation could be used for quantitative assessment of the total reserves of vitamin A in the body. The new method (3d-DRD) has the advantage of shorter procedure time for assessing vitamin A body stores compared to the conventional DRD procedure.

Technical Abstract: The isotope-dilution technique is useful for assessing vitamin A status. Up to now, the conventional deuterated-retinol-dilution (DRD) procedure is the only measure that provides a quantitative estimate of the total-body stores of vitamin A; the procedure has been validated twice in two independent laboratories by comparison of the calculated values with those obtained by direct measurement of liver biopsies. However, DRD requires that the enrichment of serum retinol with deuterated retinol should have equilibrated (reached a plateau), a process that takes ~ 3 wk to complete, before retinol isotope measurements are done. Our goal was to develop a predictive mathematical formula for quantitative assessment of the total-body stores of vitamin A in adults using a procedure that takes less time to perform since serum isotope equilibration is not required, so that blood drawing will be done at 3 d, instead of at ~3 wk, post-isotope-dosing. Serum deuterated:non-deuterated (D:H)-retinol were determined in Filipino adults (n=68) at 3 d and 20 d after a 0.015 mmol oral dose of (**2H4)-retinyl acetate, and in Guatemalan adults (n=15) at 3 d and 21 d after a 0.030 mmol dose. D:H-retinol at 20 or 21 d post-dosing with isotope were used in a mathematical formula to obtain quantitative estimates of total-body vitamin A stores which were then correlated with serum D:H-retinol at 3 d post-isotope-dosing. The relationship between these parameters is non-linear, and is described by the equation: total-body stores of vitamin A (in mmol retinol) = 0.00468 x 10**(37)(isotope dose in mmol)/D:H-retinol in serum at 3 d post-isotope-dosing. A 3d-DRD equation could be used for quantitative assessment of the total reserve of vitamin A in the body; it has the advantage of shorter procedure time compared to the conventional DRD procedure described by Furr et al.