Dietary vitamin A intakes of chinese children with adequate liver stores as assessed by the retinol isotope dilution technique

Table 2 Vitamin A status of the subjects¹

	4 ~ 6 y			7 ~ 9 y			Total
	3-d group (n = 11)	18-d group (n = 10)	P value	3-d group (n = 16)	18-d group (n = 21)	P value	(n = 58)
Serum β-carotene (µmol/L)	0.56 ± 0.16	0.41 ± 0.16	0.63	0.39 ± 0.23	0.39 ± 0.22	0.94	0.43 ± 0.21
Serum retinol (µmol/L)	1.32 ± 0.13	1.31 ± 0.19	0.98	1.22 ± 0.31	1.26 ± 0.25	0.71	1.27 ± 0.24
Serum D:H²	0.006 ± 0.003	0.014 ± 0.012	0.07*	0.009 ± 0.007	0.009 ± 0.006	0.69	0.009 ± 0.007
Estimated total body vitamin A stores (mmol retinol)³	0.35 ± 0.23	0.22 ± 0.19	0.18	0.29 ± 0.22	0.25 ± 0.13	0.58*	0.28 ± 0.19
Estimated liver vitamin A (µmol/g liver)⁴	0.51 ± 0.29	0.31 ± 0.27	0.13	0.33 ± 0.28	0.26 ± 0.15	0.37*	0.33 ± 0.25

¹ Data are presented as mean ± SD. Two samples were unresponsive in the detection of enrichment of labeled vitamin A, so n = 58. There was no significant difference between the 3-day and 18-day groups in each age group (Student’s unpaired t test for equal variances or corrected t test for unequal variances, P > 0.05. * the corrected P value)
² D:H: the ratio of deuterated (isotope-labeled) to non-deuterated (non-labeled) retinol. In a deuterated-retinol-dilution (DRD) procedure, the serum samples collected from children on 3 day or 18 day after dosing of 2.5 mg [²H₈] retinyl acetate (D₈) were used to determine the enrichment of deuterated and non-deuterated retinol by using a gas chromatograph-electron capture-negative chemical ionization-mass spectrometry (Tang et al., 1998). For 3-day DRD before the equilibrium is reached, Tang’s method (2002) was used to predict the % enrichment of deuterated retinol on day 21 after the equilibrium is reached
³ The total body vitamin A reserves were calculated by the modified Bausch-Rietz equation
⁴ Liver vitamin A reserves were estimated by assuming that the weight of the liver is 3% of body weight and that 90% of total vitamin A is in the liver

ISSN: 1471-2431