Calcium Supplements and Their Role in Colorectal Cancer Prevention
Introduction to Serrated Polyps
Calcium supplements are currently being studied for their potential protective effects against serrated polyps, which are precancerous lesions associated with colorectal cancer. Among the various types of serrated polyps, the sessile serrated adenoma (SSA) is the most prevalent premalignant polyp known to develop into colorectal cancer. Addressing the challenge of chemoprevention is crucial for reducing both the incidence and mortality rates of colorectal cancer globally.
Research Overview
Researchers from the Division of Gastroenterology and Hepatology at the University of North Carolina School of Medicine have focused on the chemoprotective effects of calcium supplements on serrated polyps.
The Vitamin D/Calcium Polyp Prevention Study
The investigation analyzed data from the Vitamin D/Calcium Polyp Prevention Study, which included participants aged 45 to 75 years who had at least one polyp detected during a colonoscopy. Participants were randomly assigned to one of four treatment groups, receiving either:
– Calcium supplements (1200 mg per day)
– Vitamin D (1000 IU per day)
– A combination of calcium and vitamin D
– A placebo
The supplementation lasted for three to five years, followed by a similar duration of routine colonoscopies for follow-up. The findings of this study were recently published in the journal *Gut*.
Findings on Calcium Supplements
Contrary to the initial hypothesis that calcium supplements would protect against serrated polyps, the results indicated that both calcium supplements and the combination of calcium and vitamin D actually increased the risk of developing serrated polyps, particularly SSAs, after the supplementation period. Notably, a subgroup analysis revealed that women and smokers supplemented with calcium or calcium and vitamin D faced greater risks compared to their counterparts. In contrast, vitamin D alone did not appear to elevate the risk of serrated polyps.
Study Limitations
Several limitations must be acknowledged regarding this study. The analysis stemmed from a larger investigation focused on conventional adenomas, whereas serrated polyps, particularly SSAs, are less common. Consequently, the limited data available diminished the statistical power of the findings. Additionally, all participants had at least one detected intestinal polyp, making it difficult to generalize the risk of increased polyp occurrence with calcium supplements to individuals without any adenomas.
Conclusion and Future Research
The researchers concluded that calcium supplements may elevate the risk of intestinal polyps in individuals with a history of colorectal serrated polyps. Specifically, women and smokers with such polyps may be at a heightened risk for developing additional polyps when taking calcium supplements. Further research is necessary to validate these findings and to broaden the study population to include patients without a history of adenomas.
Reference
Crockett SD, Barry EL, Mott LA, et al. Calcium and vitamin D supplementation and increased risk of serrated polyps: results from a randomised clinical trial. Gut. 2018.