Bioequivalence of β-carotene and retinol

摘要: For many years it was accepted that 6 mg of β-carotene were required to produce 1 vitamin A in the form retinol. The equivalence based on assumptions two-thirds dietary are not absorbed, while metabolism remaining third mol is converted Recently, bioequivalence raised 12 and objective this review re-examine data used support new ratio, especially since some these obtained developing countries where infestation with gut parasites exposure other infections common, yet influence inflammation plasma carotenoid retinol concentrations frequently ignored. Bioequivalence studies examined include those done developed countries, depletion repletion studies, feeding vegetable sources or pure supplements, helminths, interactions matrix effects using stable isotopes (SI). SI show bioefficacy conversion generally poor even for unless dose small fed regularly until equilibration reached. Retinol formation appears be inversely influenced by previous intake, amount material given current status. In spite technical complexities, more liver reserves determined pre post intervention needed evaluate different sources.