Dietary factors and risk of colorectal cancer

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

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