Bioefficacy of β-carotene dissolved in oil studied in children in Indonesia

Abstract

The efficiency of conversion of this beta-carotene in oil was 27% better than that estimated previously (1.0 microg retinol from 3.3 microg beta-carotene with an unknown cis-trans ratio). The method described can be extended to measure the bioefficacy of carotenoids in foods with high precision, requiring fewer subjects than other methods.

Bioequivalence of β‐carotene and retinol

“…The lower dose of β-carotene used (6 mg) was closer to the amounts obtained from an average vegetablecontaining diet and less than one-third of that used by Lin et al 68 and Hickenbottom et al 69 . Thus the study of Tang et al 70 suggests that bioconversion of β-carotene to retinol is better from smaller doses and would support the view that the method used by van Lieshout et al 65 has advantages over the other methods used in measuring the bioefficacy of β-carotene.…”

“…Such amounts can be obtained from the diet but the mean intake in most industrialised countries is usually less than 5 mg d −1 and the bioefficacy of conversion to vitamin A was poor. In contrast, van Lieshout et al 65 gave only 160 µg β-carotene per day and this was very efficiently converted to retinol. In the former studies, the recipients were healthy well-fed American adults, whereas in the latter the recipients were Indonesian school children of questionable inflammatory and vitamin A status.…”

“…Tracer studies on β-carotene conversion using stable isotopes Conversion of β-carotene in oil to retinol in Indonesian school children Van Lieshout and colleagues 65 used equal amounts of 13 C 10 β-carotene (160 µg, 27 RE, 0.3 µmol) and 13 C 10 retinol (160 µg, 0.56 µmol) administered daily to Indonesian children of 8-11 years. The β-carotene was symmetrically labelled to produce 13 C 5 retinol when metabolised by β-carotene 15,15 -dioxygenase.…”

“…In contrast to the method of van Lieshout et al, 65 in which small doses of the tracers were given to volunteers on a daily basis, two American studies used single doses of the retinol and β-carotene tracers after a period of approximately 23 days, during which their volunteers received a standard vitamin A intake. The same method was used in both studies and the main objective was to assess variability of β-carotene conversion to retinol, in 11 well-nourished women 68 and 11 men.…”

“…68,69,71 The exception is the study by van Lieshout et al, 65 where small amounts of 13 C 10 β-carotene and 13 C 10 retinol tracers were given daily, and bioequivalency was obtained from the ratio of plasma concentrations of 13 C 5 retinol to 13 C 10 retinol on day 21 when equilibration was achieved. The ratio obtained for bioefficacy was 0.79 mol retinol per mole β-carotene and this result is very close to those obtained from the vitamin A depleted subjects (Table 2).…”