Calcium suppletie lijkt preventief te werken in het voorkomen van darmkanker.

13 juni 2012: U kunt op de website van de Journal of the National Cancer Institute - JNCI het volledige studie rapport van onderstaande studie gratis inzien.

Bron: Journal of the National Cancer Institute, Vol. 96, No. 12, 921-925, June 16, 2004

Calcium lijkt de groei van kwaadaardige darmpoliepen tegen te gaan en is daarmee in feite preventief in het voorkomen van darmkanker. Aldus een studie gepubliceerd in de Journal of The NCI. Arts-bioloog drs. E. Valstar bevestigde ons dat calcium een sterk preventieve werking heeft op de risico's op het krijgen van darmkanker maar ook op andere soorten kanker zoals prostaatkanker.

In zijn boek: 'Voedingsinterventie bij kanker' bespreekt hij ook de werking van calcium in een behandeling van kanker met veel meer literatuurstudies dan deze, ook literatuurstudies bij mensen.

In deze gerandomiseerde dubbelblinde studie namen 930 patiënten deel bij wie eerder darmkankercellen werden gevonden. De ene groep kreeg dagelijks 1200 mg calciumcarbonaat, de andere helft een placebo. De patiënten kregen regelmatig een darmonderzoek om de aanwezigheid en de groei van kwaadaardige poliepen te controleren.

Het risico in de calciumgroep op het ontstaan van 'hyperplastische poliepen' of 'tubulaire adenomen' was respectievelijk 0,82 en 0,89. Echter, in vergelijking met de placebogroep was het risico op darmkanker in de calciumgroep 0,65. De resultaten wijzen erop dat calcium vooral effect heeft op de laatste fase van de kankervorming van de poliepen.

Hier het originele abstract van de studie:

Source: Journal of the National Cancer Institute, Vol. 96, No. 12, 921-925, June 16, 2004

Effect of Calcium Supplementation on the Risk of Large Bowel Polyps
Kristin Wallace, John A. Baron, Bernard F. Cole, Robert S. Sandler, Margaret R. Karagas, Michael A. Beach, Robert W. Haile, Carol A. Burke, Loretta H. Pearson, Jack S. Mandel, Richard Rothstein, Dale C. Snover

Affiliations of authors: Departments of Community and Family Medicine (KW, JAB, BFC, MRK, LHP), Medicine (JAB, RR), and Anesthesia (MAB), Dartmouth-Hitchcock Medical Center, Lebanon, NH; Department of Medicine, University of North Carolina, Chapel Hill (RSS); Department of Preventative Medicine, University of Southern California School of Medicine, Los Angeles (RWH); Department of Gastroenterology and Hepatology, Cleveland Clinic Foundation, Cleveland, OH (CAB); Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, GA (JSM); Department of Pathology, Fairview Southdale Hospital, and Department of Pathology, University of Minnesota, Minneapolis (DCS)

Correspondence to: John A. Baron, MD, Dartmouth Medical School, Evergreen Center, Suite 300, 46 Centerra Parkway, Lebanon, NH 03756 (e-mail: john.a.baron@dartmouth.edu)

Background: Clinical trials have shown that calcium supplementation modestly decreases the risk of colorectal adenomas. However, few studies have examined the effect of calcium on the risk of different types of colorectal lesions or dietary determinants of this effect.

Methods: Our analysis used patients from the Calcium Polyp Prevention Study, a randomized, double-blind, placebo-controlled chemoprevention trial among patients with a recent colorectal adenoma. Nine hundred thirty patients were randomly assigned to calcium carbonate (1200 mg/day) or placebo. Follow-up colonoscopies were conducted approximately 1 and 4 years after the qualifying examination. We used general estimating equation (GEE) and generalized linear regression analyses to compute risk ratios and 95% confidence intervals (CIs) to assess the effect of calcium treatment versus placebo on the risk of hyperplastic polyps, tubular adenomas, and more advanced lesions. Additionally, we used GEE analyses to compare the calcium treatment effects for various types of polyps with that for tubular adenomas. We also examined the interaction between calcium treatment and baseline intake of dietary calcium, fat, and fiber. All P values were obtained using Wald tests based on the corresponding models. All tests of statistical significance were two-sided.

Results: The calcium risk ratio for hyperplastic polyps was 0.82 (95% CI = 0.67 to 1.00), that for tubular adenomas was 0.89 (95% CI = 0.77 to 1.03), and that for histologically advanced neoplasms was 0.65 (95% CI = 0.46 to 0.93) compared with patients assigned to placebo. There were no statistically significant differences between the risk ratio for tubular adenomas and that for other types of polyps. The effect of calcium supplementation on adenoma risk was most pronounced among individuals with high dietary intakes of calcium and fiber and with low intake of fat, but the interactions were not statistically significant.

Conclusion: Our results suggest that calcium supplementation may have a more pronounced antineoplastic effect on advanced colorectal lesions than on other types of polyps.

-------------------------------------------------------------------------------- This article has been cited by other articles in Highwire Press-hosted journals:
Schatzkin, A., Peters, U. (2004). Advancing the Calcium-Colorectal Cancer Hypothesis. J Natl Cancer Inst 96: 893-894