The following are risk factors for colorectal carcinoma:
- animal fat intake:
- the relative risk for the highest intake quintile versus the lowest intake quintile is 1.89 (95% confidence 1.13 to 3.15)
- women eating beef, pork or lamb daily have a relative risk of colorectal cancer of 2.49 vs women who eat these meats less than once per month
- dietary fibre intake:
- trials suggest that vegetable fibre and not cereal fibre are effective in reducing colorectal cancer
- migrant studies indicate that when populations move from a low-risk area (e.g. Japan) to a high-risk area (e.g. the USA), the incidence increases rapidly within the first generation of migrants
- diet is definitely the most important exogenous factor identified up to now in the aetiology of colorectal cancer
- association between consumption of ultra-processed foods and risk of colorectal cancer:
- a study found that high consumption of total ultra-processed foods in men and certain subgroups of ultra-processed foods in men and women was associated with an increased risk of colorectal cancer (2):
- compared with those in the lowest fifth of ultra-processed food consumption, men in the highest fifth of consumption had a 29% higher risk of developing colorectal cancer and the positive association was limited to distal colon cancer (72% increased risk)
- associations remained significant after further adjustment for body mass index or indicators of nutritional quality of the diet (that is, western dietary pattern or dietary quality score).
- no association was observed between overall ultra-processed food consumption and risk of colorectal cancer among women
- among subgroups of ultra-processed foods, higher consumption of meat/poultry/seafood based ready-to-eat products among men and ready-to-eat/heat mixed dishes among women was associated with increased risk of colorectal cancer
- yogurt and dairy based desserts were negatively associated with the risk of colorectal cancer among women
Calcium intake as a protective factor in colorectal cancer:
A prospective study of more than half a million UK women conducted over almost 17 years showed (3):
- research team, led by the University of Oxford, tracked the intake of 97 dietary factors in 542,778 women from 2001 for an average of 16.6 years
- during this period 12,251 participants developed colorectal cancer
- calcium intake showed the strongest protective effect, with each additional 300 mg per day – equivalent to a large glass of milk – associated with a 17% reduced RR (relative risk)
- six dairy-related factors associated with calcium – dairy milk, yogurt, riboflavin, magnesium, phosphorus, and potassium intakes – also demonstrated inverse associations with colorectal cancer risk
- alcohol showed the reverse association, with each additional 20 g daily – equivalent to one large glass of wine – associated with a 15% RR increase
- weaker associations were seen for the combined category of red and processed meat, with each additional 30 g/per day associated with an 8% increased RR for colorectal cancer
- study authors concluded that dairy products help protect against colorectal cancer, and that this is driven largely or wholly by calcium
Yoghurt and Risk of Proximal Colorectal Cancer
A systematic review and meta-analysis revealed that the frequency of yogurt consumption was associated with a reduced risk of proximal colon cancer with a long latency period (4):
- In this study it was commented that "..the stronger association of proximal colon cancer with yogurt consumption at baseline observed in our study may reflect the longer latency period, relevant for the cancer of this site in its multistage process. Indeed, our latency analyses point towards a 16–20-year latency for the association between yogurt consumption and overall CRC incidence..."
A study investigated the consumption of yoghurt and incidence of Bifidobacterium-positive colorectal cancer (5):
- evidence indicates that probiotics such as yogurt may play a cancer-preventative role via their effect on the intestinal microbiota composition and/or intestinal barrier function.
- among important probiotic bacterial strains in yogurt, Bifidobacterium is suggested to have a tumor-suppressive effect
- tested the hypothesis that the association of long-term yogurt intake with colorectal cancer incidence might differ by the abundance of tumor tissue Bifidobacterium
- the study authors hypothesized that long-term yogurt intake might be associated with colorectal cancer incidence differentially by tumor subgroups according to the amount of tissue Bifidobacterium
- previous study evidence showed that Bifidobacterium-positive colorectal cancer was associated with signet ring cell histology but not with other tumor characteristics or prognosis in colorectal cancer patients
- the link between tissue Bifidobacterium abundance and the signet ring cell feature potentially implies that loss of epithelial cellular adhesion (observed in signet ring cells) might cause the entry of Bifidobacterium into colonic tissues
- other study evidence study also suggests that tumor Bifidobacterium might be an indicator of dysfunctional intestinal barriers in colorectal cancer
- Ugai et al observed such a differential association, especially for proximal colon cancer, with a trend of the association of yogurt intake with lower incidence of Bifidobacterium-positive proximal colon cancer (but not Bifidobacterium-negative subtype)
Reference:
- (1) Labianca R et al. Primary colon cancer: ESMO Clinical Practice Guidelines for diagnosis, adjuvant treatment and follow-up. Ann Oncol. 2010;21 Suppl 5:v70-7.
- (2) Wang L, Du M, Wang K, Khandpur N, Rossato S L, Drouin-Chartier J et al. Association of ultra-processed food consumption with colorectal cancer risk among men and women: results from three prospective US cohort studies BMJ 2022; 378 :e068921 doi:10.1136/bmj-2021-068921
- (3) Papier, K., Bradbury, K.E., Balkwill, A. et al. Diet-wide analyses for risk of colorectal cancer: prospective study of 12,251 incident cases among 542,778 women in the UK. Nat Commun16, 375 (2025)
- (4) Sun J et al . Higher Yogurt Consumption Is Associated With Lower Risk of Colorectal Cancer: A Systematic Review and Meta-Analysis of Observational Studies. Front Nutr. 2022 Jan 3;8:789006.
- (5) Ugai, S et al. Long-term yogurt intake and colorectal cancer incidence subclassified by Bifidobacterium abundance in tumor. Gut Microbes 2025; 17(1)