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The Science Nook on Colorectal Cancer

As March approaches, we acknowledge Colorectal Cancer Awareness Month.  Colorectal cancer (CRC) is the third most common cancer diagnosis worldwide. The majority of colorectal tumors start as benign polyps and evolve into cancerous tumors, sometimes taking twenty years or more to develop [i].  Strongly influential in the development of CRC are nutrition and lifestyle habits, and when practiced proactively, may influence later progression of the disease.  Twenty years is plenty of time to take ownership of healthy dietary and lifestyle habits, which may in turn, lower or prevent the risk for colorectal cancer.


Established risk factors for CRC include:

  • High intake of red and processed meat
  • Consistent alcohol consumption
  • Western type diet, full of calorie-dense, highly processed foods and lower in fruits, vegetables and whole grains[ii].  
  • Chronic intestinal inflammation, like that seen in Crohn’s disease (CD) and ulcerative colitis (UC), has also been established as factors in the development of colorectal polyps [iii].


It’s not clear why this dietary pattern or these chronic diseases influence colon cancer risk.  Current research is focusing on how the diet affects the bacteria that live in the colon in order to better understand if inflammation is a factor.  In addition, the Mediterranean diet has been shown to lower the risk of colon and rectal cancer.  A recent study in the International Journal of Epidemiology further supports this.


Study 1

The Mediterranean diet and risk of colorectal cancer in the UK women’s cohort study


Journal: International Journal of Epidemiology


The Mediterranean Diet, rich in olive oil, fish, red wine, tea, fruits and vegetables, and other fiber sources, contributes various nutrients involved in anti-inflammatory processes within the body. These compounds include antioxidants from fruits and vegetables, and healthy omega-3 fatty acids and polyunsaturated fatty acids from fish and olive oil.  In addition, the higher intake of fish and poultry instead of red meat helps decrease exposure to carcinogens present in cooked and heated red meats.  The Mediterranean diet is also naturally lower in refined sugar which may also help prevent colorectal cancer by improving insulin resistance and decreasing circulating levels of IGF-1, a hormone associated with cancer risk [i].

In this study, 35,372 women were followed for a median of 17.4 years. Each woman was given a  217-item food frequency questionnaire which was scored on a scale from 0-10, with 10 being maximum adherence to the Mediterranean diet pattern. The women with the highest scores tended to have higher energy intakes, lower alcohol intake, more engagement in exercise, and more likelihood of being vegetarians and fish eaters, compared to the women with lower scores. As a result, the women adhering to a Mediterranean type diet may have a lower risk of colorectal cancer [iv].


For the patient and caregiver

Taking control of the diet is one great way to take control of your cancer journey.  Making healthy dietary changes is important.  Whether you have benign colorectal polyps or you have been diagnosed with active colorectal cancer, being proactive by implementing healthy nutrition habits is important.  Set gradual and attainable goals, such as going meat-free for one day per week.  It is also important to be realistic with your goals and not change everything in your diet all at once.  Start by aiming to include some key components of the Mediterranean diet:

  • Eat primarily a plant-based diet including fresh fruits and vegetables, whole grains, legumes and nuts.
  • Replace butter with olive oil.
  • Season foods with herbs and spices instead of salt.
  • Limit red meat and processed meat to no more than a few times a month.
  • Consume a moderate intake of  fish and poultry.
  • Choose fish rich in omega-3 fatty acids, such as tuna, herring, salmon, and sardines.
  • For dessert, choose fresh fruit. Save sweets such as ice cream or cake for special celebrations.
  • Enjoy meals with family and friends.


For the healthcare team

Proper nutrition for colorectal cancer patients plays a role in their ability to handle treatments, surgery or other medical procedures [v]. Support your patient by creating meal plans that are compatible with the patient’s dietary preferences and/or restrictions and that can be modified according to current symptoms. Assist the patient who is ready to make more drastic dietary changes by mapping out weekly goals that can be easily achieved, and brainstorm ways to move towards a plant focused diet. Enlist the patient’s family and friends to help grocery shop, cook meals, and provide encouragement.  All of these suggestions will help the patient not only be successful in optimizing their nutrition, but also help prevent recurrence and maintain overall health.


[i] Donovan MG, Selmin OI,Doetschman TC and Romagnolo DF(2017) Mediterranean Diet:Prevention of Colorectal Cancer.Front. Nutr. 4:59.doi: 10.3389/fnut.2017.00059
[ii] American Cancer Society: Colorectal Cancer Risk Factors  [Internet]. [cited 2018 Feb 18]. Available from:https://www.cancer.org/cancer/colon-rectal-cancer/causes-risks-prevention/risk-factors.html
[iii] Terzic J, Grivennikov S, Karin E, Karin M. Inflammation and colon cancer. Gastroenterology (2010) 138:2101–14.e5. doi:10.1053/j.gastro.2010.01.058
[iv] Jones, P, Cade, JE , Evans, CEL  et al. (2017) The Mediterranean diet and risk of colorectal cancer in the UK women’s cohort study. International Journal of Epidemiology, 46 (6). pp. 1786-1796. ISSN 0300-5771
[v] Shoemaker, L.; Estfan, B.; Induru, R.; Walsh, D. Symptom management: an important part of cancer care. 2011. Cleveland Clinic Journal of Medicine. 78(1) Pp 25-34
Tasha Feilke MS, RD, CSO, LDN

Clinical Operations

Tasha is a registered dietitian as well as a Massachusetts licensed dietitian. She obtained her Master’s of Science in Nutrition at Bastyr University in Washington state and completed her dietetic internship at San Francisco State University. She has worked in various inpatient, outpatient,and community settings in Seattle and the Bay Area since 2005. Prior to her move to Boston in 2014 she worked exclusively at the Alta Bates Comprehensive Cancer Center in Berkeley, CA. Tasha is passionate about motivating people to reach their fitness and nutrition goals throughout all stages and conditions of life and believes food can truly serve as medicine.

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