CASEINOPHOSPHOPEPTIDE ON IRON BIOAVAILABILITY

INFLUENCE OF TWO FORMS OF

CASEINOPHOSPHOPEPTIDE ON IRON BIOAVAILABILITY

I.B. Kibangou

, S. Bouhallab

, F. Bureau

, P. Guerin

, S. Allouche

, P.

Arhan

, D. Bouglé

1

Laboratoire de Physiologie Digestive et Nutritionnelle (EA 3216), CHU, Caen France t

2

Institut de Recherches de Technol

2

ogie Laitière, INRA, Rennes, France,

L aboratoire de Biochimie A, CHU, Caen, France

Introduction: Iron deficiency is the most common nutritional problem around the world, both in developed and in developing countries. The main cause of this deficiency is its low bioavailability (5-10 %). Previous studies showed that phosphopeptides derived from casein hydrolysis of whole casein improves Fe absorption [1], but phosphopeptides (CPP) released by enzyme digestion of different caseins give conflicting results [2, 3]; that could impose restrictions to their widespread application in functional foods for man. CPP can be found in several different forms of structure but only two of them are important (ȕCPP(1- 25), Įs

CPP (59-79)).The objective of this study was to evaluate the absorption of iron complexed to those two main forms of purified CPP (Fe-ȕCPP(1-25), Fe-Įs

CPP (59-79)) using the human intestinal Caco-2 cells model.

Methods: CPPs were first purified by Fast Protein Liquid chromatography on an anion exchange column, characterized by electrospray mass spectrometry (ESI-MS) coupled with HPLC (625 LC system) and complexed with Fe (Fe- ȕCPP(1-25), Fe-Įs

CPP (59-79)). Three iron transport solutions were prepared by mixing Fe complexes (Fe-ȕCPP(1-25), Fe-Įs

CPP (59-79)) and ferrous sulphate (control) with special Dulbecco’s Modified Eagle Medium without iron (100 µmoles/l Fe ). Bioavailability was assessed by applying the samples to human intestinal Caco-2 cells grown on filters for 21 days (n = 6) and incubating at 37 °C for 2 hours. Iron absorption was measured by Atomic absorption spectrometer (Perkin Elmer, 1100B).

Results: Uptake and net absorption of Fe-Įs

CPP (59-79)) complex were significantly lower (p<0.0001) than ferrous sulphate and Fe-ȕCPP(1-25) Net absorption of Fe-ȕCPP(1-25) complex was higher than ferrous sulphate (Table).

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222 I.B. Kibangou et al.

Table: Influence of two main forms of caseinophosphopeptides on iron bioavailability

Total uptake Net absorption

(%Fe) (%Fe)

Ferrous sulphate (control) 7.78 ± 1.14 2.71 ± 0.07 Fe-ȕCPP(1-25) 6.69 ± 0.25 3.505 ± 0.25

Fe-Įs

CPP (59-79) 1.87 ± 0.28**

1.53 ± 0.22

Mean ± SD; ANOVA, p<0,01; **: different from Fe-ȕCPP(1-25) (p < 0,0001);

: different from ferrous sulphate group (p < 0,0001)

Conclusion: This study give for the first time experimental evidence to explain the conflicting results on the conflicting effects of caseins and their peptides on iron absorption [2,3] about cow milk proteins: ȕCPP(1-25) and Įs

CPP (59-79)) have opposite influences on iron bioavailability; Įs

CPP (59-79) inhibits iron absorption as opposed to ȕCPP(1-25) that creates its absorption improvement.

The enhancing effect of ȕ casein, which the main casein of breast milk could explain part of its enhancing effect on iron absorption.

References:[1] Hurell and al., (1989). Iron absorption in humans as influenced by bovine milk proteins; Am. J. Clin. Nutr., 49: 546-552 ;[2] Bouhallab et al., (1999). Sensitivity of b-caseinophosphopeptide-iron complex to digestive enzymes in ligated segment of rat duodenum ; J. Nutr. Biochem., 10: 723-727; [3] Yeung and al., (2002). Effects of iron source on iron availability from casein and casein phophopeptides; J. Food. Sci., 12: 292- 299

Keywords: Iron uptake; Caseinophosphopeptides; Caco-2 cells