Lifestyle, Nutrition, and Colorectal Cancer

Colorectal cancer continue to rise in patients under the age of 50 years. People under the age of 50 also tend to have more aggressive colorectal cancers, which is a prime example of a condition that could be prevented with lifestyle interventions. Screening for colorectal cancer begins at 50 years of age, and early detection is highly correlated with decreased mortality.
This 2018 data line up with a study from 2017, which found a 22% increased rate of colon cancer in people under the age of 50, as well as an increased risk of death from colon cancer in this younger group.
Many factors are likely to contribute, including:
Alcohol use: Moderate and heavy alcohol use raises the risk of colorectal cancer.
Oral health: Although still emerging, research suggests poor oral health may raise the risk for colorectal cancer. A recent study links periodontal disease to increased risk of colorectal cancer. Periodontitis may be a risk factor for many cancers, especially smoking-related cancers Tooth loss has also been correlated with increased risk for colorectal cancer, possibly due to associated Fusobacteria.
Processed meat consumption: Processed meat is known to have carcinogenic effects, and the International Agency for Research on Cancer concludes that it contributes to colorectal cancer.
RECOMMENDATIONS FOR AT-RISK PATIENTS
High fruit and vegetable consumption appears to be protective. Research supports the benefits of a high-fibre, low-meat diet to prevent colorectal cancer. Diets with lower overall nutrition are linked to many forms of cancer, including colorectal. In addition, consumption of green tea has strong research support as preventative for colorectal cancer, primarily in cohort and case-controlled studies in Asia and America. Finally, the importance of screening cannot be understated. One estimate has found that 79% of "averted colorectal cancer deaths" were due to prevention by removing adenomatous polyps which reinforces the notion that colorectal screening is critical for patients at risk.

References
Ansa BE, Coughlin SS, Alema-Mensah E, Smith SA. Evaluation of colorectal cancer incidence trends in the United States (2000-2014). J Clin Med. 2018;7(2):E22. doi:3390/jcm7020022.
Siegel RL, Miller KD, Fedewa SA, et al. Colorectal cancer statistics, 2017. CA Cancer J Clin. 2017;67(3):177-193. doi:3322/caac.21395.
Lee D, Jung KU, Kim HO, Kim H, Chun HK. Association between oral health and colorectal adenoma in a screening population. Medicine (Baltimore). 2018;97(37):e12244. doi:1097/MD.0000000000012244.
Johnson CM, Wei C, Ensor JE, et al. Meta-analyses of colorectal cancer risk factors. Cancer Causes Control. 2013;24(6):1207-1222. doi:1007/s10552-013-0201-5.