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

Abstract

Objective: The current meta-analysis evaluated the association between vitamin B 12 intake and blood vitamin B 12 level and colorectal cancer (CRC) risk. Design: The PubMed and EMBASE databases were searched. A dose-response analysis was performed with generalized least squares regression, with the relative risk (RR) and 95 % CI as effect values. Setting: The meta-analysis included seventeen studies. Subjects: A total of 10 601 patients. Results: The non-linear dose-response relationship between total vitamin B 12 intake and CRC risk was insignificant (P = 0·690), but the relationship between dietary vitamin B 12 intake and CRC risk was significant (P < 0·001). Every 4·5 μg/d increment in total and dietary vitamin B 12 intake was inversely associated with CRC risk (total intake: RR = 0·963; 95 % CI 0·928, 0·999; dietary intake: RR = 0·914; 95 % CI 0·856, 0·977). The inverse association between vitamin B 12 intake and CRC risk was also significant when vitamin B 12 intake was over a dosage threshold, enhancing the non-linear relationship. The non-linear dose-response relationship between blood vitamin B 12 level and CRC risk was insignificant (P = 0·219). There was an insignificant association between every 150 pmol/l increment in blood vitamin B 12 level and CRC risk (RR = 1·023; 95 % CI 0·881, 1·187). Conclusions: Our meta-analysis indicates that evidence supports the use of vitamin B 12 for cancer prevention, especially among populations with high-dose vitamin B 12 intake, and that the association between CRC risk and total vitamin B 12 intake is stronger than between CRC risk and dietary vitamin B 12 intake only.

Dietary B vitamin and methionine intakes and risk for colorectal cancer: a case–control study in China

“…Some (10)(11)(12)(13)(14)(15) , but not all (16)(17)(18)(19)(20)(21)(22) , epidemiological studies reported an inverse association between folate intake and colorectal cancer risk. Similarly, inverse associations between vitamin B 2 , vitamin B 6 and vitamin B 12 and colorectal risk have been observed in some studies (23)(24)(25)(26)(27) . The evidence that methionine affects colorectal cancer is limited.…”

Dietary intake of vitamin B₁₂ in relation to diet and lifestyle characteristics in a population at high risk for colorectal cancer

“…The majority of studies that looked at the role of B complex vitamins, primarily folate in oncogenesis were focused on C-1 metabolism (20,21). So far, studies are inconclusive on the role dietary intake of vitamin B 12 has in CRC (13)(14)(15)(22)(23)(24). Some studies showed positive relation between intake of vitamin B 12 and lower risk of CRC (13)(14)(15), while others showed no effect for other forms of gastric cancers (24).…”

“…Sun et al (22) in their meta-analysis show that high total intake of vitamin B 12 (from diet and supplements combined) has an inverse relation with CRC risk if the intake is > 12 µg/day. Also, the association is stronger than if only dietary vitamin B 12 is considered.…”

“…While studies are still inconclusive regarding dietary intake of vitamin B 12 (13)(14)(15)(22)(23)(24), high contribution from milk and dairy can be observed as a potential modulator of CRC risk, probably attributable to its high content of calcium (8,45). Strong inverse correlation was found between intake of calcium (dietary and supplemental) and total cancer risk, and risk of cancers of digestive system, especially CRC (46,47).…”

“…The study was designed to test the relevance of dietary intake of vitamin B 12 , total and from major food sources for CRC risk observed as diet and lifestyle characteristics which have been shown to either increase or reduce the risk of CRC (1,2,8). Hypothesis presented by Kurbel et al (19) and inconclusive findings on the role vitamin B 12 has in CRC (13)(14)(15)(22)(23)(24) were the reason why focus was put on vitamin B 12 .…”