Oral calcium suppresses increased rectal epithelial proliferation of persons at risk of colorectal cancer.

Area of Science:

• Gastroenterology
• Oncology
• Nutritional Science

Background:

• High-fat, high-phosphate, low-fiber diets promote colonic carcinogenesis.
• Individuals at risk for colon cancer often exhibit increased rectal epithelial proliferation.

Purpose of the Study:

• To investigate the effect of oral calcium supplementation on rectal epithelial cell proliferation in high-risk individuals.
• To determine if calcium intake can suppress a potential marker for colorectal malignancy.

Main Methods:

• A cohort of 35 high-risk volunteers received 1.25-1.5 g of elemental calcium daily for three months.
• Rectal biopsies were analyzed for cell proliferation using tritiated thymidine labeling before, during, and after treatment.
• The labeling index (LI) and crypt cell position were assessed.

Main Results:

• Oral calcium significantly decreased the mean labeling index (LI) by 36% (p < 0.001) during treatment.
• The reduction in LI was most pronounced in the basal three-fifths of the crypts.
• A 10% increase in mean crypt cell number was observed during calcium treatment.

Conclusions:

• Oral calcium supplementation effectively suppresses rectal epithelial proliferation in individuals at risk for colon cancer.
• A reduced LI may serve as a biomarker for potential malignancy.
• Further randomized trials are warranted to confirm these findings and support dietary interventions.