|Tako, Elad -|
|Laparra, Jose -|
|Lei, Xingen -|
|Kelly, James -|
|Rutzke, Mike -|
|Miller, Dennis -|
Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 14, 2009
Publication Date: April 2, 2009
Citation: Tako, E., Glahn, R.P., Laparra, J.M., Welch, R.M., Lei, X., Kelly, J.D., Rutzke, M.A., Miller, D.D. 2009. Iron and zinc bioavailabilities to pigs from red and white beans (Phaseolus vulgaris L.) are similar. Journal of Agricultural and Food Chemistry. 57(8):3134-3140. Interpretive Summary: Common beans contain relatively high concentrations of iron (Fe) and zinc (Zn) but are also high in polyphenols and phytates, factors that may inhibit Fe and Zn absorption. Our lab has developed a model for studying mineral absorption from different foods and food combinations. Food samples undergo a simulated digestion and are placed over Caco-2 cells, which act as a mimic of the intestinal lining. Previous studies have shown that polyphenols show an inhibitory effect on mineral absorption. This study compared our cell model and using pigs as an in vivo model to compare Fe and Zn bioavailabilities between red and white beans, which differ in polyphenol content. It was concluded that bean color does not affect iron or zinc bioavailability in pigs and that beans are a good source of iron and zinc.
Technical Abstract: Common beans contain relatively high concentrations of iron (Fe) and zinc (Zn) but are also high in polyphenols and phytates, factors that may inhibit Fe and Zn absorption. In vitro (Caco-2 cells) and in vivo (pigs) models were used to compare Fe and Zn bioavailabilities between red and white beans, which differ in polyphenol content. Bean/maize diets containing 37% of either white or red cooked beans were formulated. Fe uptake by Caco-2 cells was 14-fold higher from the white bean diet compared to the red bean diet. The diets were fed to anemic piglets (n = 10) for 35 days. On experiment days 7 and 21, pigs were given meals containing beans intrinsically labeled with stable isotopes of Fe and Zn (58 Fe, 70Z n), followed by intravenous (iv) injections of 54Fe and 67 Zn, to assess Fe and Zn absorption. Isotope ratios determined by inductively coupled plasma mass spectrometry in whole blood and plasma samples were used to calculate iron and zinc absorption, respectively. On day 35, animals were killed and duodenal sections were collected for DMT1 gene expression analysis. Fe absorption was 14 and 16% from the first labeled meal and 9 and 10.5% from the second labeled meal for the white and red beans, respectively (P > 0.05). Zn absorption was 28 and 23% from the first meal (P > 0.05) and 31 and 29% from the second meal (P > 0.05) for the white and red beans, respectively. DMT1 gene expression did not differ between treatments. It was concluded that bean color does not affect Fe or Zn bioavailability in vivo and that beans are a good source of bioavailable Fe and Zn.