Dietary Supplements May Affect CRC Risk, But Research is Inconsistent
the MPR take:
Use of dietary supplements is increasing in countries where colorectal cancer (CRC) is present, but is there an association between supplement use and CRC risk? A new study in the International Journal of Cancer presents a systematic review and meta-analysis of 24 prospective cohort studies on dietary supplement use and CRC risk using research published up to January 2013. A statistically significant inverse relationship was observed between use of multivitamin and calcium supplements and CRC risk; in six studies, an increase of 100mg/day of supplemental calcium was linked with a significantly reduced risk of CRC. For vitamins A, C, D, and E, plus garlic and folic acid, either no associations or inconsistent results were observed (such as from dietary vs. supplemental sources). However, the potential role of lifestyle factors in CRC risk and methodological variables in the assessed research to limit these study results. In the future, research should take into account recall of supplement use, duration of supplement use, type of supplement clearly defined, seasonal influences, and lifestyle factors for improved results.
Use of dietary supplements is rising in countries where colorectal cancer is prevalent. We conducted a systematic literature review and meta-analyses of prospective cohort studies on dietary supplement use and colorectal cancer risk. We identified relevant studies in Medline, Embase and Cochrane up to January 2013.
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