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Diets Rich in Dairy Lower Risk of Colorectal Cancer

    Various fresh dairy products on wooden background to illustrate how dairy foods may protect against colorectal cancer.

    Written by: Jyoti Madhusoodanan, Ph.D. | Issue # 125 | 2025

    • Colorectal cancer, the third most common cancer globally, is strongly associated with diet and lifestyle.
    • Across 97 dietary factors, alcohol, red, and processed meats were most strongly linked to a higher risk of colorectal cancer. 
    • Dairy products were protective and reduced risk by up to 17 percent. 
    • The protective effects of dairy products are likely because of their calcium content. 

    In the largest single study to correlate diet and cancer risk, researchers found that the boost of calcium contained in milk, dairy products, and other foods can cut the risk of colorectal cancer by as much as 17 percent [1]. 

    Colorectal cancer is the third most common cancer, with nearly 2 million cases reported globally in 2022. The disease is most prevalent in high-income countries including the US, Europe, Japan, and Australia. Rates are lower, albeit on the rise, in low and middle-income countries. Diet and lifestyle are strongly associated with the risk of colorectal cancer. 

    In a 2018 report [2] from the World Cancer Research Fund & American Institute for Cancer Research, experts concluded that consuming more than two alcoholic drinks per day and eating processed meat or red meat increased the risk of colorectal cancer, and eating fiber-rich foods and dairy likely reduced the risk. But strong connections between many foods and colorectal cancer have been elusive – in part because it is difficult to measure various elements of people’s diets over long-running, large studies. 

    For the new study, researchers tracked how 97 dietary factors were associated with colorectal cancer rates in more than 500,000 women in the U.K over a total of about 16 years. During that time, 12,251 women were diagnosed with the condition. The researchers found that women who developed colorectal cancer were older than the overall cohort. They were also more likely to have a family history of bowel cancer and had more adverse health behaviors, such as smoking. 

    The research team found that diets with higher amounts of calcium-rich foods, such as milk and yogurt, were linked to a lower risk of developing colorectal cancer. Other nutrients, such as magnesium, potassium, and riboflavin, were also protective — likely because they’re also abundant in calcium-rich foods, the authors wrote in the study.  Other calcium-rich foods, such as dark leafy greens, were also linked to lower risk of cancer. 

    Precisely why calcium is so beneficial was not examined in this study. But evidence from other research offers clues: studies in rats and other models, for example, have shown that calcium can bind bile acids in the intestine and protect the mucosal lining from damage; prevent DNA damage and promote programmed cell death, which can clear away aging or pre-cancerous cells. In a press release, nutritional epidemiologist Keren Papier of the University of Oxford, who led the work, said these possibilities might explain calcium’s benefits. “It’s suggested that calcium might protect against bowel cancer by binding to bile acids and free fatty acids to form a type of a harmless ‘soap’, which stops them from damaging the lining of our gut,” Papier said in a press release. 

    All dairy products – except cheese and ice cream – were linked to the benefits of calcium-rich foods. In addition to calcium, other chemicals in milk and dairy products may confer additional protection. Experiments in animal models have shown that butyric acid and sphingomyelin, which are also present in many dairy products, may block cancer-causing chemicals from triggering the disease.  

    Other studies, using data from the UK Biobank [3] and the Nurses’ Health Study II [4], have found similar links between dietary calcium and a lower risk of colorectal cancer. But a study using data from the China Kadoorie Biobank found an opposite effect: in that work, where 3350 cases occurred among more than 500,000 participants, researchers reported that milk consumption increased cancer risk by about eight percent. “It is possible that the association between dairy milk and colorectal cancer risk might differ in populations where a large majority cannot digest lactose,” the authors wrote in the study. 

    Overall, the study’s results confirm well-established correlations between alcohol, red meat and processed meats with colorectal cancer risk. The data also reveals a strong protective role for calcium-rich foods, including milk and other dairy products, but more work is needed to understand the overall benefits and risks of dietary calcium. 

    References

    1. Papier K, Bradbury KE, Balkwill A, Barnes I, Smith-Byrne K, Gunter MJ, Berndt SI, Le Marchand L, Wu AH, Peters U, Beral V. Diet-wide analyses for risk of colorectal cancer: prospective study of 12,251 incident cases among 542,778 women in the UK. Nature Communications. 2025 Jan 8;16(1):375.
    2. World Cancer Research Fund International. Diet, nutrition, physical activity and cancer: a global perspective: a summary of the Third Expert Report. World Cancer Research Fund International; 2018.
    3. Bradbury KE, Murphy N, Key TJ. Diet and colorectal cancer in UK Biobank: a prospective study. InternationalJjournal of Epidemiology. 2020 Feb 1;49(1):246-58.
    4. Kim H, Hur J, Wu K, Song M, Wang M, Smith-Warner SA, Zhang X, Giovannucci EL. Total calcium, dairy foods and risk of colorectal cancer: a prospective cohort study of younger US women. International Journal of Epidemiology. 2023 Feb 1;52(1):87-95.