Can the Mediterranean diet reduce colon cancer risk?

Can the Mediterranean diet reduce colon cancer risk?

Frontier Voice of Nutrition Remarks (December 20, 2011)

Nalin Siriwardhana, PhD, interviewed Prof. Zora Djuric from the Departments of Family Medicine and Environmental Health Sciences at the University of Michigan

Diet and cancer expert, Prof. Zora Djuric, highlighted that the Mediterranean diet contains promising active compounds to reduce colon cancer risk. According to her most recent publication in the Nutrition Review journal, the Mediterranean diet contains not only plenty of beneficial components such as fruits, vegetables, herbs, fish, and olive oil but also low levels of harmful fats and red meat.

Unhealthy inflammation associated with unhealthy dietary patterns can increase colon cancer risk. Further, she added that the colon cancer risk is high for those who live in parts of the industrialized world such as the United States. Although in Greece, where people routinely consume a Mediterranean diet, the colon cancer rate is very low. However, the rate has increased among the people who migrated from Greece to industrialized countries. Using validated scientific information, Prof. Djuric clearly explained that the Mediterranean diet has multiple beneficial effects to lower colon cancer risk and improve colon health.

Nutrition Remarks interviewed Prof. Djuric due to the importance of her information for public health. A simplified version of the conversation is as follows:

Question from Nutrition Remarks: What are the major differences between a Mediterranean diet and a typical American or Western diet?

Answer from Dr. Djuric: The Mediterranean diet has higher amounts of plant-based foods like fruits, vegetables, herbs, cereals, legumes, and olive oil compared to the American or Western diet. Also, a Mediterranean diet has a higher variety of plant-based nutrients than the American or Western diet. The Mediterranean diet also includes plentiful fish while American and Western diets contain more red meat/meat products. Another significant difference is that the Mediterranean diet contains beneficial olive oil, but the American and Western diets contain high levels of other fats such as trans fats from processed foods and saturated fats from meat.

Question: Why is the variety of fruits and vegetable important?

Answer: Different fruits, vegetables, and herbs contain different beneficial compounds such as anti-oxidants, vitamins, minerals, and nutrients. Importantly, different fruits, vegetables, and herbs also contain different types and amounts of beneficial phytochemicals such as resveratrol, catechins, flavonoids, carotenoids, etc. Therefore, the preventive benefits are increased with increased varieties versus using a single or few varieties in the diet.

Question: What is the link between colon cancer and inflammation?

Answer: There are multiple links between inflammation and cancer. Specifically, one of the harmful compounds produced by omega 6 fats is associated with inflammation in the colon. It is called prostaglandin E2 (PGE2), and this metabolite of omega-6 fats is well-known to be increased in colon cancer. Omega-3 fats, such as those found in fish, cannot be metabolized to form harmful PGE2. Instead omega-3 makes PGE3 that is less inflammatory.

Question: Howdoes the Mediterranean diet reduce inflammation?

Answer: The Mediterranean diet can reduce inflammation in several ways.

Fish contain higher levels of beneficial omega-3 fats called eicosapentaenoic acid (EPA) and docashexanoic acid (DHA). EPA plays a major role by reducing PGE2 production, thus greatly reducing inflammation.

Several anti-inflammatory phytochemicals such as resveratrol, catechins, flavonoids, carotenoids, etc. have multiple benefits including PGE2-reducing effects.

Components of a Mediterranean diet have activities similar to the popular multifunctional drug aspirin. Like aspirin, compounds in the Mediterranean diet can also reduce PGE2 and the enzymes that produce PGE2, called cyclooxygenase (COX), to reduce inflammation. Dr. Rothwell from the University of Oxford showed that long-term aspirin use can reduce colon cancer risk.

Original work: Zora Djuric , The Mediterranean diet: Effects on proteins that mediate fatty acid metabolism in the colon. Nutrition ReviewsVol. 69, No. 12, 730-744 (2012).

Written by Nalin Siriwardhana, PhD

Zora Djuric, PhD, is a Research Professor in the Departments of Family Medicine and Environmental Health Sciences (Nutrition program) at the University of Michigan. She is also a member of the University of Michigan Comprehensive Cancer Center. Dr. Djuric has expertise with research on cancer risk biomarkers related to different dietary patterns, focusing mainly on clinical studies. Her studies have typically included individuals at increased cancer risk. Her current focus is on colon cancer prevention using a Mediterranean exchange list diet.

More about Prof. Zora Djuric and work

http://sitemaker.umich.edu/fm-zdjuric/research

http://www.med.umich.edu/opm/newspage/2007/meddiet.htm

http://www.med.umich.edu/cancer/news/med_diet10.shtml

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