Colorectal Cancer Protective Effects and the Dietary Micronutrients Folate, Methionine, Vitamins B6, B12, C, E, Selenium, and Lycopene

Abstract

The data reported here were obtained from the case-control arm of a large, comprehensive, population-based investigation of colorectal cancer incidence, etiology, and survival, the Melbourne Colorectal Cancer Study, conducted in Melbourne, Australia. This part of the case-control study was designed to identify dietary factors associated with colorectal cancer risk in 715 incident cases compared with 727 age/sex frequency-matched randomly chosen community controls, in which a quantitative assessment of all foods eaten was made. New data are presented on the potential of two groups of micronutrients as protective agents, namely, those involved in DNA methylation, synthesis, and repair (folate, methionine, and vitamins B6 and B12) and those with antioxidant properties (selenium, vitamins E and C, and lycopene). The adjusted odds ratios showed that for folate there was significant protection for rectal cancer in second and third quintiles of consumption but not for colon cancer, and this was similar for methionine consumption. Vitamin B6 consumption was significantly protective for both colon and rectal cancer at the higher quintiles, and this was similar for vitamin B12. Dietary selenium was significantly protective at middle quintiles of consumption at both cancer sites. Dietary vitamins E and C were statistically significantly protective for both colon and rectal cancer at all levels of consumption, and for both vitamins there was a dose-response effect of increasing protection, particularly so for colon cancer. Lycopene was not associated with colorectal cancer risk. A combined model included vitamins E, C, and B12 and selenium as micronutrients protective for colorectal cancer and folate, which, however, showed an increased risk at the highest level of consumption. These data support the proposition that a diet containing the dietary micronutrients involved in DNA methylation (folate, methionine, and vitamins B6 and B12) and some of those with antioxidant properties (selenium and vitamins E and C) may have a role to play in lowering colorectal cancer risk and also that such protection can be achieved by dietary means alone.

Protective Effects of Beetroot Extract against Phenyl Hydrazine Induced Anemia in Rats

“…23 Diet low in folic acid may increase risk of breast, pancreatic, and colon cancer. [24][25][26] Its low level in body may also predispose to coronary artery disease. 27 Ascorbic acid is an important component of human diet.…”

Biomarkers Related to One-Carbon Metabolism as Potential Risk Factors for Distal Colorectal Adenomas

“…Cho and colleagues (3) previously reported a positive association of choline intake and an inverse association of betaine intake with distal colorectal adenoma risk among women, whereas no associations were observed with colorectal cancer among men (4). Methionine intake was not associated with colorectal cancer risk in several studies (5)(6)(7)(8)(9)(10)(11)(12)(13). However, the associations of plasma concentrations of methionine, choline, and betaine with risk of colorectal adenomas or carcinomas have not been studied so far.…”

A dose–response meta-analysis reveals an association between vitamin B12and colorectal cancer risk

“…The fourteen studies of vitamin B 12 intake included a total of 9693 cases (Table 1) (11)(12)(13)(14)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38) . The studies were conducted in Asia, Europe and North America, and were published between 2008 and 2013.…”

“…Recent studies have shown that one-carbon metabolism may be related to colorectal carcinogenesis (9,10) . Therefore, vitamin B 12 deficiency may increase CRC risk (11,12) . However, several studies have reported that vitamin B 12 is not associated with the risk of CRC (13,14) , or that folic acid plus vitamin B 12 is associated with increased cancer risk (15) .…”