Vitamin A equivalence of spirulina β‐carotene in US men

Abstract

To evaluate the vitamin A value of spirulina β‐carotene and to assess dose‐related responses, spirulina was grown in a 23 atom% 2H2O cultural solution, harvested, made as capsules, and fed to volunteers. Spirulina β‐carotene showed the highest abundance of enrichment as [2H10] trans β‐carotene. Eight healthy US male subjects (51±6 y) with a mean serum retinol concentration of 1.7 ±0.3 μmole/L and a BMI of 23 ± 3 kg/m2 consumed 5.8 μmole (2.0 mg) of [13C10] retinyl acetate in oil as a reference dose with a standard liquid breakfast containing 13 g of fat (day 1). At day 8, each subject was randomly assigned to consume 4 g or 2 g of spirulina containing 5.1 (2.8 mg) or 2.6 (1.4 mg) μmoles of trans β‐carotene with the same standard breakfast as day 1. Serum samples were collected at various time points over 50 days. Concentrations and enrichments of retinol and β‐carotene in serum samples were determined by using HPLC and GC/MS0.A comparison of the mean area‐under‐the‐curve (AUC) for the total labeled serum retinol response after the 4 g (n=4) or 2 g (n=4) of spirulina, with the AUC of the reference dose of 2.0 mg [13C10]retinyl acetate, did not show differences related to the amount of dose taken. The mean vitamin A equivalence of spirulina β‐carotene to retinol was 2.7 and 2.8 to 1 by weight, for the 4 g or 2 g spirulina doses, respectively. (Funded by the Nestle Foundation).