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Bioavailability of Zn from biofortified rice assessed in a Caco–2 cell model and in suckling rat pups
Author(s) -
Du Xiaogu,
Jou MingYu,
Hotz Christine,
Lonnerdal Bo
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.718.9
Subject(s) - bioavailability , digestion (alchemy) , biofortification , chemistry , small intestine , food science , caco 2 , zinc , zoology , biochemistry , in vitro , biology , chromatography , pharmacology , organic chemistry
Biofortification is a sustainable method of increasing the micronutrient content of staple foods. We assessed the bioavailability of Zn from biofortified and conventional varieties of rice by two methods. Rice samples were digested with pepsin in vitro at pH 2 or pH 4, followed by pancreatin digestion at pH 7. Uptake of 65 Zn from labeled rice samples into Caco‐2 cells was measured after 6 h. Rat pups were intubated with 65 Zn‐labeled undermilled and polished conventional rice varieties and Zn biofortified rice. Pups were killed after 6 h and tissues were collected for radioactivity measurements. Means of radioactivity in Caco‐2 cells were 3.5±0.9% and1.9±0.2% after digestion at pH 2 and 4, respectively. Corresponding cellular Zn uptake ranged from 0.39 to 1.01 μmole Zn/g and 0.20 to 0.53 μmole Zn/g of cellular protein. In rat pups, means of radioactivity were 0.8, 5.4, 2.8, 10.7, 27.3, and 53.0 % in stomach, perfused small intestine, perfusate, liver, carcass, and cecum‐colon, respectively. Mean whole body (perfused small intestine, liver, and carcass) 65 Zn uptake varied from 36% to 59%. Zn uptake in rat pups and by Caco‐2 cells after digestion at pH 2 were closely correlated for all rice varieties (r=0.53, p<0.05), and especially for polished rice (r=0.79, p<0.05). Zn uptake in rat pups and by Caco‐2 cells after digestion at pH 4 were closely correlated for under‐milled rice (r = 0.78, p < 0.05). Since uptake of Zn by rat pups has been shown to be closely correlated to results from human adults it is likely that this cell model can be used for screening of Zn bioavailability from staple foods. This study was supported by HarvestPlus.