Vitamin A equivalence of spirulina beta-carotene in Chinese adults as assessed by using a stable-isotope reference method.
BACKGROUND
Spirulina is a high-protein food supplement that contains carotenoids.


OBJECTIVE
The objective of the study was to determine the vitamin A equivalence of spirulina beta-carotene in humans.


METHODS
Spirulina was grown in a 23 atom% (2)H(2)O cultural solution. Spirulina beta-carotene showed the greatest enrichment as [(2)H(10)]trans beta-carotene. Ten healthy Chinese men with a mean (+/-SD) serum retinol concentration of 1.7 +/- 0.3 micromol/L and a body mass index (in kg/m(2)) of 23 +/- 3 consumed 5.8 micromol [(13)C(10)]retinyl acetate in oil as a reference dose with a breakfast containing 13 g fat. One week later, each subject consumed 7.9 mumol trans beta-carotene in spirulina with a breakfast containing 22 g fat. All subjects followed diets low in carotenoid and vitamin A. Forty blood samples were collected from each subject over a span of 56 d. Concentrations and enrichments of retinol and beta-carotene in serum samples were determined by using HPLC and a mass spectrometer.


RESULTS
Compared with the serum response to [(13)C(10)]retinyl acetate dose, the mean conversion factor of spirulina beta-carotene to retinol was 4.5 +/- 1.6 (range: 2.3-6.9) by weight. It was estimated that 80% of the conversion occurred within the first 24 h after spirulina administration.


CONCLUSIONS
In a group of well-nourished, normal-weight Chinese men following low-vitamin A diets, 4.5 mg spirulina beta-carotene consumed with 22 g fat has the same vitamin A activity as does 1 mg retinyl acetate.
National Institute for Nutrition and Food Safety, Beijing, China.
Jie
J
Wang
Yin
Y
Wang
Zhixu
Z
Wang
Lei
L
Li
Jian
J
Qin
Weiqi
W
Lai
Ying
Y
Fu
Paolo M
PM
Suter
Robert M
RM
Russell
Michael A
MA
Grusak
Guangwen
G
Tang
Shian
S
Yin
D000328:Adult; D015992:Body Mass Index; D002338:Carotenoids / Q000097:blood; D002681:China; D003903:Deuterium; D004032:Diet; D005215:Fasting; D006801:Humans; D007553:Isotope Labeling; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D053545:Spirulina; D013810:Therapeutic Equivalency; D014801:Vitamin A / Q000008:administration & dosage* / Q000097:blood*; D019207:beta Carotene / Q000008:administration & dosage*
D019207:beta Carotene; D014801:Vitamin A; D002338:Carotenoids; D003903:Deuterium