Calcium carbonate suppresses haem toxicity markers without calcium phosphate side effects on colon carcinogenesis.

Ossama Allam (1) , Diane Bahuaud (1) , Sylviane Taché (1) , Nathalie Naud (1) , Denis E. Corpet (1) , Fabrice H.F. Pierre (1)

1 Xénobiotiques

Red meat intake is associated with an increased risk of colorectal cancer. We have previously shown that haemin, Hb and red meat promote carcinogen-induced preneoplastic lesions, aberrant crypt foci (ACF), in the colon of rats. We have also shown that dietary calcium phosphate inhibits haemin-induced promotion and normalises faecal lipoperoxides and cytotoxicity. Unexpectedly, high-calcium phosphate control diet-fed rats had more preneoplastic lesions in the colon than low-Ca control diet-fed rats. The present study was designed to find a Ca supplementation with no adverse effect, by testing several doses and types of Ca salts. One in vitro study and two short-term studies in rats identified calcium carbonate as the most effective Ca salt to bind haem in vitro and to decrease faecal biomarkers previously associated with increased carcinogenesis: faecal water cytotoxicity and thiobarbituric acid-reactive substances. A long-term carcinogenesis study in dimethylhydrazine-injected rats demonstrated that a diet containing 100 μmol/g calcium carbonate did not promote ACF, in contrast with a previously tested calcium phosphate diet. The results suggest that calcium carbonate, and not calcium phosphate, should be used to reduce haem-associated colorectal cancer risk in meat eaters. They support the concept that the nature of the associated anion to a protective metal ion is important for chemoprevention.

Mots clés: Red meat; Haem; prevention; colon cancer; Calcium; Colorectal cancer; Lipid peroxidation

Domaines: Cancer

Ossama Allam, Diane Bahuaud, Sylviane Taché, Nathalie Naud, Denis E. Corpet, et al.. Calcium carbonate suppresses haem toxicity markers without calcium phosphate side effects on colon carcinogenesis.. Br J Nutr, 2010, 105 (3), pp.1-8. ⟨10.1017/S0007114510003624⟩. ⟨hal-00553174⟩