Bioconversion of plant carotenoids to vitamin A in Filipino school-aged children varies inversely with vitamin A status.
BACKGROUND
It is important to understand the factors affecting strategies to improve the vitamin A status of populations. We reported previously that a 3-d deuterated-retinol-dilution (DRD) procedure might be used to indicate total body stores of vitamin A.


OBJECTIVE
We studied the ability of 3-d DRD to detect changes in the body pool size of vitamin A and the effect of vitamin A status on the bioconversion of plant carotenoids to vitamin A.


METHODS
Two separate, unrelated studies were conducted in 7-13-y-old children with poor or marginal serum retinol concentrations (0.32-0.93 micromol/L) by feeding them controlled diets daily for 5 d/wk for 12 wk, after treatment with an anthelmintic drug. In school 1 (n = 27), lunch and 2 snacks that were provided at school contained 2258 retinol equivalents/d (mostly from orange fruit and vegetables) and 5.3 MJ/d from 33 g fat, 37 g protein, and 209 g carbohydrates; in school 2 (n = 25), 2 snacks provided 2.5 MJ/d from 9.4 g fat, 9.6 g protein, and 119 g carbohydrates, but no carotenes.


RESULTS
In school 1, mean serum beta-carotene increased from 0.12 to 0.62 micromol/L (P = 0.0001) and serum retinol increased from 0.68 to 1. 06 micromol/L (P = 0.0001). In school 2, serum beta-carotene increased from 0.06 to 0.11 micromol/L (P = 0.0001) and serum retinol increased from 0.66 to 0.86 micromol/L (P = 0.0001). In school 1, but not school 2, improvement in serum retinol varied inversely with baseline retinol (r = -0.38, P = 0.048). In both schools, 3-d DRD showed reductions in the ratio of serum deuterated to nondeuterated retinol (D:H retinol) postintervention, denoting improvements in vitamin A status; the higher D:H retinol (ie, the poorer the status) at baseline, the greater the reduction in D:H retinol postintervention (school 1: r = -0.99, P = 0.0001; school 2: r = -0.89, P = 0.0001).


CONCLUSIONS
Three-day DRD can detect changes in the body pool size of vitamin A, although a predictive equation to quantitate total body stores of vitamin A with the use of 3-d data needs to be developed. Bioconversion of plant carotenoids to vitamin A varies inversely with vitamin A status; improvement in status after dietary interventions is strongly influenced by total body stores of vitamin A and is influenced little or not at all by serum retinol.
Nutrition Center of the Philippines, Manila. jribaya@hnrc.tufts.edu
J D
JD
Ribaya-Mercado
F S
FS
Solon
M A
MA
Solon
M A
MA
Cabal-Barza
C S
CS
Perfecto
G
G
Tang
J A
JA
Solon
C R
CR
Fjeld
R M
RM
Russell
D000293:Adolescent; D000871:Anthelmintics / Q000627:therapeutic use; D002338:Carotenoids / Q000378:metabolism*; D002648:Child; D002664:Child Nutritional Physiological Phenomena; D003903:Deuterium; D005260:Female; D006801:Humans; D008297:Male; D010272:Parasitic Diseases / Q000188:drug therapy; D010679:Philippines; D010944:Plants; D011237:Predictive Value of Tests; D014801:Vitamin A / Q000096:biosynthesis* / Q000097:blood*; D014802:Vitamin A Deficiency / Q000517:prevention & control*
D000871:Anthelmintics; D014801:Vitamin A; D002338:Carotenoids; D003903:Deuterium