I’ve been reading about why red meat is associated with higher colon cancer risk. Initially it was thought it was because of the fat in the meat, but this has changed. It may due to protein.
Worldwide, red meat consumption in countries matches colon cancer incidence perfectly. Countries where people eat a lot of red meat such as US, Europe, and South America have the highest incidence. Countries like Japan, China, and the Far East, which have increased their intake of red meat with the westernization of diet, have the highest increase of colon cancer incidence. Japan, a country which used to have the lowest incidence of colon cancer, has now a higher incidence than the USA. Japan has a dramatic shortage of oncologists to deal with the increasing number of cases.
Dr. Eunyoung Cho from Harvard published an interesting paper in 2007 showing that choline, which is found in red meat, promotes the growth of polyps. He studied over 39,000 female US nurses enrolled in the Nurses Health Study. He found that women with the highest intake of choline had 45% higher risk of developing a polyp. Choline is a nutrient found in red meat, but also in eggs, poultry, and wheat germ.
We need to be cautious because this study does not prove that choline causes polyps or that avoiding it prevents them, but it warrants further study to better understand the relationship of choline and colon polyps.
There is still ongoing discussion about what red meat is (versus processed meat). Pepperoni is a red meat. Would that mean that lots of pepperoni pizza means a high intake of red meat in studies? In another study on diet and colon cancer, a 21% increase in colorectal cancer risk for each 1.7 ounces of processed (smoked, salted, cured, chemical preservatives) meat was found. We know that nitrates, present in most preserved meats you find in the grocery, have been found to be associated with colon cancer risk.
However there are interesting questions about whether it makes a difference if you eat quality grass-fed meats, fatty or not. In addition, the preparation of meat has an impact on colorectal cancer and polyp risk. Cooking “low and slow” is the safest way, along with avoiding chemically-preserved meats.
There are interesting data, for example, that Argentina, known for its beef, has lower incidence of colorectal cancer than the United States, and that groups such as Mormons, who love meat, have lower incidence than vegetarians groups. This raises the question of how important alcohol and smoking are.
There is still to learn a lot about the role of red meat.