Folate intake and colorectal cancer risk: a meta-analytical approach. Int J Cancer

Cancer Research U.K., Epidemiology Unit, University of Oxford, Oxford, United Kingdom. <>
International Journal of Cancer (Impact Factor: 5.09). 02/2005; 113(5):825-8. DOI: 10.1002/ijc.20648
Source: PubMed


Adequate consumption of folate may reduce the risk of colorectal cancer. We performed a meta-analysis of 7 cohort and 9 case-control studies that examined the association between folate consumption and colorectal cancer risk. In cohort studies, the association between folate consumption and colorectal cancer risk was stronger for dietary folate (folate from foods alone; relative risk for high vs. low intake = 0.75; 95% CI = 0.64-0.89) than for total folate (folate from foods and supplements; relative risk for high vs. low intake = 0.95; 95% CI = 0.81-1.11) and there was no significant heterogeneity between studies. There was significant heterogeneity between case-control studies. These results offer some support for the hypothesis that folate has a small protective effect against colorectal cancer but confounding by other dietary factors cannot be ruled out.

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Available from: Naomi E Allen, Nov 21, 2014
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    • "The role that B 9 vitamin folate and its synthetic form, FA, play in colorectal cancer (CRC) development remains controversial [5] [6] [7]. Some epidemiological studies report that high dietary and blood folate levels inhibit CRC development [8] [9]. However, more recent data from epidemiological and clinical trial studies suggest that high FA intake and subsequent high serum levels may actually increase cancer risk [10] [11]. "
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    ABSTRACT: Folate and its synthetic form, folic acid (FA), are essential vitamins for the regeneration of S-adenosyl methionine molecules, thereby maintaining adequate cellular methylation. The deregulation of DNA methylation is a contributing factor to carcinogenesis, as alterations in genetic methylation may contribute to stem cell reprogramming and dedifferentiation processes that lead to a cancer stem cell (CSC) phenotype. Here, we investigate the potential effects of FA exposure on DNA methylation and colonosphere formation in cultured human colorectal cancer (CRC) cell lines. We show for the first time that HCT116, LS174T, and SW480 cells grown without adequate FA demonstrate significantly impaired colonosphere forming ability with limited changes in CD133, CD166, and EpCAM surface expression. These differences were accompanied by concomitant changes to DNA methyltransferase (DNMT) enzyme expression and DNA methylation levels, which varied depending on cell line. Taken together, these results demonstrate an interaction between FA metabolism and CSC phenotype in vitro and help elucidate a connection between supplemental FA intake and CRC development. Copyright © 2015. Published by Elsevier Inc.
    Full-text · Article · Mar 2015 · The Journal of nutritional biochemistry
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    • "A meta-analysis of 6 randomized, controlled trials (RCTs) of folic acid supplementation reported a possible increased risk of any cancer [45], although another meta-analysis found folic acid supplementation to be associated with 40% to 50% reductions in risks of esophageal, gastric, and pancreatic cancers [46]. Investigations of the effects of folate on colorectal cancer risk have had conflicting results, with protective effects shown for dietary folate and effects ranging from modestly protective to potentially harmful associated with supplementation with folic acid (the synthetic form of folate) [47-52]. "
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    ABSTRACT: A balanced and varied diet is the best source of essential vitamins and minerals; however, nutrient deficiencies occur, including in populations with bountiful food supplies and the means to procure nutrient-rich foods. For example, the typical American diet bears little resemblance to what experts recommend for fruit, vegetables, and whole grains, which serve as important sources of an array of vitamins and minerals. With time, deficiencies in one or more micronutrients may lead to serious health issues. A common reason people take multivitamin and mineral (MVM) supplements is to maintain or improve health, but research examining the effectiveness of MVMs in the prevention of certain chronic conditions is ongoing. In addition to the utility of MVMs for filling in relatively small but critical nutritional gaps, which may help prevent conditions such as anemia, neural tube defects, and osteoporosis, some evidence supports possible benefits of MVM supplementation with regard to cancer prevention (particularly in men) and prevention or delay of cataract, as well as some aspects of cognitive performance. Unlike some single-vitamin supplements, MVM supplements are generally well tolerated and do not appear to increase the risk of mortality, cerebrovascular disease, or heart failure. The potential benefits of MVM supplements likely outweigh any risk in the general population and may be particularly beneficial for older people.
    Full-text · Article · Jul 2014 · Nutrition Journal
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    • "The result of a systematic review, including seven prospective studies and nine case–control studies, shows that the association between folic acid intake in diet and CRC (RR = 0.75; 95% CI: 0.64–0.89) is stronger than dietary folic acid plus folic acid supplements (RR = 0.95; 95% CI: 0.81–1.11).44 "
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    ABSTRACT: Cancer is a worldwide problem as it will affect one in three men and one in four women during their lifetime. Colorectal cancer (CRC) is the third most frequent cancer in men, after lung and prostate cancer, and is the second most frequent cancer in women after breast cancer. It is also the third cause of death in men and women separately, and is the second most frequent cause of death by cancer if both genders are considered together. CRC represents approximately 10% of deaths by cancer. Modifiable risk factors of CRC include smoking, physical inactivity, being overweight and obesity, eating processed meat, and drinking alcohol excessively. CRC screening programs are possible only in economically developed countries. However, attention should be paid in the future to geographical areas with ageing populations and a western lifestyle.19,20 Sigmoidoscopy screening done with people aged 55-64 years has been demonstrated to reduce the incidence of CRC by 33% and mortality by CRC by 43%.
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