Vegetarian diet reduces risk of colon cancer

I am a fan of Big Macs and burgers in general but there is no denying the mountain of evidence supporting the healthfulness of vegetarian diets. In particular, they are very good at reducing risk for heart disease. According to the American Heart Association:

"Most vegetarian diets are low in or devoid of animal products. They’re also usually lower than nonvegetarian diets in total fat, saturated fat and cholesterol. Many studies have shown that vegetarians seem to have a lower risk of obesity, coronary heart disease (which causes heart attack), high blood pressure, diabetes mellitus and some forms of cancer."

The last part ("... and some forms of cancer.") may come as a surprise to some people, but there are multiple corroborating studies (e.g. link). The most recent is a new paper that shows that a vegetarian diet reduces colorectal cancer risk (HPH):

"For the study, researchers at Loma Linda University in California analyzed the dietary habits of more than 70,000 people. Those who ate a vegetarian diet had a 22% lower risk of colorectal cancer than those who weren’t vegetarians. Among those who ate a vegetarian diet that included fish, the reduction in risk was even greater — 43%. A vegetarian diet that includes fish and other seafood is called a pescovegetarian diet."

All of the people in the study belonged to the Seventh-day Adventist churches which reduced some of the variation caused by confounding factors. As a group, the church members do not eat a lot of meat, but among those who are vegetarians, they experienced a 22% lower rate of colon cancer than those who ate meat. Interestingly, among the vegetarians, those who ate fish actually had an even lower rate (43% reduction).

There are several possible explanations for why a vegetarian diet may reduce risk of colon cancer:

"There are other ways a vegetarian diet may protect against colorectal cancer: It’s possible that something in red meat or the way it is cooked encourages the growth of colorectal cancer. That goes double for processed red meats. Eating more plant foods provides extra beneficial nutrients such as folate, calcium, and fiber that may protect against colorectal cancer."

Vegetarian diets can be healthful and nutritionally sound if they are carefully planned to include essential nutrients. It is important to note that a vegetarian diet can be unhealthy if it contains too many calories and/or saturated fat and not enough important nutrients. Most importantly, a vegetarian diet can reduce the risk of both heart disease and certain types of cancer.

Figure 1. A vegetarian diet can be both tasty and reduce the risk of colon cancer.