Researchers from the Cancer Epidemiology Unit at the University of Oxford, in collaboration with international institutions, have made significant findings regarding the relationship between diet and colorectal cancer risk. Through a study involving 542,778 women in the United Kingdom, the researchers discovered a positive correlation between alcohol consumption and colorectal cancer, as well as a protective role for calcium and dairy-related foods.
Colorectal cancer is the third most common cancer globally, with nearly 2 million cases reported in 2022. While incidence rates are higher in high-income countries, they are also on the rise in lower-income regions. It has been observed that migrants who adopt the dietary habits of high-risk countries tend to experience changes in their colorectal cancer risk, indicating the influence of modifiable factors in the development of this type of cancer.
Certain nutrients, foods, and beverages are suspected to play a role in colorectal cancer risk, including known carcinogens like alcohol and processed meat. However, there is still a lack of comprehensive data on how specific dietary components affect the risk of developing colorectal cancer.
The study, titled “Diet-wide analyses for risk of colorectal cancer: prospective study of 12,251 incident cases among 542,778 women in the UK,” was published in Nature Communications. The researchers aimed to address the uncertainties surrounding the association between diet and colorectal cancer by conducting a large-scale, diet-wide analysis.
Participants in the study were drawn from the Million Women Study, a cohort of middle-aged UK women who completed detailed dietary questionnaires on 97 dietary factors. The data from 542,778 women was collected over an average of 16.6 years, during which 12,251 cases of incident colorectal cancer were diagnosed.
The analysis involved multivariable models that adjusted for demographic, lifestyle, and clinical factors. Genetic data from various sources were also included in the study. The results showed that alcohol and red/processed meats are indeed carcinogens, with alcohol consumption and red/processed meat intake being linked to an increased risk of colorectal cancer. Conversely, calcium was found to have a protective effect, potentially due to its role in binding gut bile acids and reducing carcinogenic exposure in the colon.
Consumption of calcium-rich foods such as dairy milk, yogurt, and magnesium, riboflavin, and potassium were associated with a reduced risk of colorectal cancer. Further analysis suggested that calcium was primarily responsible for these associations. Genetic analysis revealed that individuals with genetic variants linked to higher milk consumption had a significantly lower risk of colorectal cancer.
In addition to calcium, several other dietary components were linked to a reduced risk of colorectal cancer. These included whole grains, breakfast cereals, fruits, leafy greens, vitamin C, and fiber. However, the protective effects of these components were somewhat diminished when other lifestyle and dietary factors were taken into account.
Sensitivity analyses confirmed the findings across different subsites of colorectal cancer and ruled out reverse causation. The study highlights the need for further research to explore the protective mechanisms of calcium and evaluate the health implications of high calcium intake.
This groundbreaking research provides valuable insights into the relationship between diet and colorectal cancer risk, paving the way for future studies and potential interventions to reduce the burden of this disease.
References:
1. Papier, K., et al. (2025). Diet-wide analyses for risk of colorectal cancer: prospective study of 12,251 incident cases among 542,778 women in the UK. Nature Communications. DOI: 10.1038/s41467-024-55219-5.
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