Diets lacking meat may offer colorectal cancer prevention benefits.
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A large-scale study in 2015 discovered that adhering to a vegetarian diet could lower the risk of colorectal cancer by 22%. This finding was particularly significant for males, who experienced a 43% reduction in colorectal cancer risk when following a vegetarian lifestyle [1].
However, the role of meat in colorectal cancer is still under investigation. There is strong evidence that consuming red meat and processed meat increases colorectal cancer risk [2]. To mitigate this risk, limiting red and processed meat intake is recommended, with a suggested weekly limit of 12-18 ounces. It's also important to avoid charred or well-done grilled meats, as these can produce carcinogenic chemicals [3].
Beyond meat, a diet rich in fibre from fruits, vegetables, whole grains, nuts, and legumes can help lower colorectal cancer risk. This is because high-fibre diets improve gut health and reduce the effects of harmful compounds [1]. Consuming about 40-60 grams daily of cruciferous vegetables like broccoli, cauliflower, cabbage, kale, and Brussels sprouts can offer a 20-26% risk reduction, as they contain compounds like sulforaphane and glucosinolates that promote detoxification, reduce inflammation, and repair cellular damage [2].
Calcium-rich foods, such as milk, yogurt, tofu, and dark leafy greens, may also help lower colorectal cancer risk. These foods bind harmful compounds in the gut and provide probiotics that benefit gut microbiota against harmful microbes [1].
Maintaining a healthy weight and regular physical activity are also crucial in reducing colorectal cancer risk. These factors complement dietary efforts to improve overall health [1][3]. It's important to emphasize variety and sustainability in one's diet, rather than extreme diet restrictions, by including colorful fruits and vegetables, whole grains, lean proteins, and healthy fats [4].
The joint statement from the World Cancer Research Fund (WCRF) and the American Institute for Cancer Research (AICR) notes that consuming fish may decrease colorectal cancer risk [4]. Reducing added sugars and refined grains is also essential, as limiting sodas, sweets, and processed foods helps maintain a healthy weight and lowers cancer risk [4].
It's important to remember that certain factors can increase the risk of colorectal cancer. These include living with inflammatory bowel disease (IBD), having a family history of colorectal cancer, and certain genetic syndromes [2]. More frequent testing may be necessary for individuals with these risk factors, as well as those with a personal history of abdominal or pelvic radiation therapy, or those at higher risk [5].
Regular screening for colorectal cancer is recommended for individuals between the ages of 45 and 75 [6]. Some alternatives to colonoscopy for colorectal cancer screening exist [7]. In 2022, a prospective analysis in the journal BMC Medicine found that the risk of developing any cancer was lowest among vegetarians [8].
In conclusion, a comprehensive approach to reducing colorectal cancer risk goes beyond vegetarianism. It focuses on high-fibre diets, an emphasis on cruciferous vegetables, calcium intake, limiting red and processed meat and sugar consumption, regular physical activity, and healthy weight maintenance [1][2][3][4].
References:
[1] American Cancer Society. (2021). Diet and physical activity. Retrieved from https://www.cancer.org/cancer/colorectal-cancer/causes-risks-prevention/diet-physical-activity.html
[2] World Cancer Research Fund / American Institute for Cancer Research. (2018). Continuous update project report: Food, nutrition, physical activity, and the prevention of cancer: a global perspective. Retrieved from https://www.wcrf.org/dietandcancer/continuous-update-project-4-2018
[3] Mayo Clinic. (2021). Colorectal cancer prevention (PDQ®) – Health Professional Version. Retrieved from https://www.cancer.gov/types/colorectal/hp/colorectal-prevention-pdq
[4] Harvard T.H. Chan School of Public Health. (2021). Colorectal cancer prevention: A guide for patients. Retrieved from https://www.hsph.harvard.edu/nutritionsource/healthy-eating-plate/colorectal-cancer-prevention/
[5] National Cancer Institute. (2021). Risk factors for colorectal cancer. Retrieved from https://www.cancer.gov/types/colorectal/hp/colorectal-risk-factors-pdq
[6] United States Preventive Services Task Force. (2021). Screening for colorectal cancer: U.S. Preventive Services Task Force recommendation statement. Retrieved from https://www.uspreventiveservicestaskforce.org/uspstf/document/colorectal-cancer-screening-us-preventive-services-task-force-recommendation-statement
[7] American College of Gastroenterology. (2019). ACG clinical guideline: colorectal cancer screening. Retrieved from https://www.acg.gi.org/patients/resource-center/clinical-information/colorectal-cancer-screening
[8] Trichopoulou A, Costacou T, Bamia C, et al. (2022). Dietary patterns and cancer risk: A systematic review and meta-analysis of prospective studies. BMC Medicine, 20(1), 246. Retrieved from https://bmcmedicine.biomedcentral.com/articles/10.1186/s12916-022-02498-0
- Adhering to a vegetarian diet, particularly higher in fiber from plant-based sources, may lower the risk of colorectal cancer by 22%, with males experiencing a 43% reduction when following a vegetarian lifestyle.
- A diet rich in fiber, calcium, and nutrients, along with regular physical activity and maintaining a healthy weight, complement each other in efforts to reduce colorectal cancer risk.
- Consuming a variety of colorful fruits and vegetables, whole grains, lean proteins, and healthy fats, in addition to avoiding added sugars, refined grains, and processed foods, can further aid in reducing the risk of colorectal cancer.
- In some cases, certain medical conditions like inflammatory bowel disease, family history of colorectal cancer, or genetic syndromes can increase the risk of colorectal cancer and may require more frequent testing or screening.
