A comprehensive analysis of dietary factors and colorectal cancer risk in 542,778 UK women found calcium intake, particularly from dairy products, is strongly associated with reduced cancer risk, while alcohol and red/processed meat consumption increase risk.
The study, published in Nature Communications, followed participants for an average of 16.6 years, during which 12,251 women developed colorectal cancer. For every 300 mg increase in daily calcium intake, colorectal cancer risk decreased by 17%. Calcium’s protective effects may relate to its ability to bind bile acids and free fatty acids in the colon, reducing their carcinogenic potential. Additional mechanisms may include reducing oxidative DNA damage and promoting epithelial cell differentiation.
Comparisons with prior research, such as the World Cancer Research Fund’s findings, show alignment but indicate a larger protective effect in this study. Earlier meta-analyses reported a 9% reduction in risk per 300 mg/day calcium intake, highlighting the potential impact of refined methodologies.
Non-dairy calcium sources were analyzed but did not show a statistically significant protective effect compared to dairy sources. This distinction underscores the potential importance of dairy-derived calcium in cancer prevention.
Using genetic analysis through Mendelian randomization, the researchers found that individuals with genetic variants associated with higher milk consumption had a 40% reduced risk of colorectal cancer per 200 g/day of predicted milk intake, compared to a 14% reduction in observational data. These findings further support calcium’s role in cancer prevention.
The study also confirmed established risk factors. Each 20 g increase in daily alcohol consumption was associated with a 15% higher risk, and red and processed meat consumption showed an 8% increased risk per 30 g daily increase.
This large-scale study benefited from robust methodology, including a well-defined cohort, Mendelian randomization techniques, and adjustments for potential confounders, enhancing confidence in its conclusions.
Conflict of interest disclosures are available in the study, ensuring transparency in the research process. The authors note that findings may not generalize to populations with high rates of lactose intolerance, as calcium consumption patterns differ significantly.
