(Download) "Calcium and Vitamin D and Risk of Colorectal Cancer: Results from a Large Population-Based Case-Control Study in Newfoundland and Labrador and Ontario (Quantitative Research) (Report)" by Canadian Journal of Public Health " eBook PDF Kindle ePub Free
eBook details
- Title: Calcium and Vitamin D and Risk of Colorectal Cancer: Results from a Large Population-Based Case-Control Study in Newfoundland and Labrador and Ontario (Quantitative Research) (Report)
- Author : Canadian Journal of Public Health
- Release Date : January 01, 2011
- Genre: Law,Books,Professional & Technical,
- Pages : * pages
- Size : 341 KB
Description
Diet has long been regarded as one of the most important environmental factors associated with colorectal cancer (CRC). (1) Since 1980 when Garland and Garland proposed that the inverse association between ultraviolet-B and colon cancer risk was mediated through vitamin D, (2) numerous studies have been done to explore the relationships among calcium, vitamin D and CRC risk. (3-18) Calcium has been hypothesized to protect against CRC by binding secondary bile acids and ionized fatty acids in the colon lumen to form insoluble calcium soaps, thereby reducing their proliferative effects on the colonic mucosa. (19) The roles of dietary calcium and vitamin D are correlated since vitamin D regulates the absorption of calcium. (20) In addition to its indirect role in maintaining calcium homeostasis, the direct genomic action of vitamin D is linked to a multitude of biological responses, including the synthesis of DNA and prevention of double-strand breaks by exogenous or endogenous sources. (20) Dairy products contain large amounts of calcium and vitamin D through fortification. It has been shown that calcium, especially in combinations as found in milk, effectively precipitates luminal cytotoxic surfactants and thus inhibits colonic cytotoxicity. (21,22) Jarvinen et al. (23) indicated that individuals with a high consumption of milk have a potentially reduced risk of colon cancer; however, the association did not appear to be due to intake of calcium, vitamin D, or to specific effects of fermented milk. Recent research indicates that calcium and vitamin D might act together, rather than separately, to reduce risk of CRC. (24) Results from a multicentre, placebo-controlled randomized clinical trial found that calcium supplementation was inversely associated with adenoma recurrence only when vitamin D levels were above the median (29.1 ng/ml). (25)