Study: Vegetables Cut Colon Cancer Risk

Submitted by Advocate Christ Medical Center

A diet consisting primarily of fruits and vegetables is associated with a significantly lower risk of all colorectal cancers. Particularly notable is the reduced risk among “pescetarians,” persons who also eat fish and other seafood as part of their dietary habits.

Those are the findings of a North American study involving 77,659 Seventh Day Adventist men and women who were followed for more than seven years. Published online in March by JAMA Internal Medicine, the study demonstrated that vegetarians, compared to non-vegetarians, had a 22 percent lower risk of developing all colorectal cancers – 19 percent lower risk for colon cancer specifically and 29 percent lower risk for rectal cancer.

The colorectal cancer risk was even less — 43 percent — for vegetarians who also ate fish and 8 percent lower in semi-vegetarians, researchers note. For vegans – those who consume no foods from animals, including milk, eggs and other dairy products — the risk for colorectal cancer was reduced by 16 percent.

Colorectal cancer is the second leading cause of death in the United States. “Much attention has focused on improving screening for and treatment of colorectal cancer, but enhancing primary prevention through risk-factor reduction remains an important objective,” researchers write. “Dietary factors have been implicated as important sources of modifiable risk for colorectal cancer…The evidence that red meat, especially processed meat, consumption is linked to increased risk and that foods containing dietary fiber are linked to decreased risk has been judged convincing.”

The study demonstrates a possible causal relationship between a vegetarian diet and the risk for colorectal cancer, but other lifestyle decisions also may be involved, says Charles Berkelhammer, M.D., gastrointestinal specialist at Advocate Christ Medical Center. “Vegetarians in the study were reported to have higher educational levels, to exercise, and to have a lower body mass index. They also were less likely to smoke —now or in the past — or to drink alcohol.

“This study corroborates other studies showing that consuming fish, and less red meat in the diet, is associated with a lower risk for colorectal cancer,” Berkelhammer said.

Although researchers set out to determine whether vegetarian dietary patterns were associated with a reduction in the risks for cancers of the colon and rectum, they also found that vegetarians participating in the study had lower mortality, lower prevalence of obesity and hypertension and a reduced incidence of type II diabetes mellitus.

The dietary choices that each person makes may prove “important for primary prevention of colorectal cancers,” study authors conclude. “That vegetarian diets similar to those of our study participants may be associated with a reduced risk of colorectal cancer, along with prior evidence of the potential reduced risk of obesity, hypertension, diabetes and mortality, should be considered carefully in making dietary choices and in giving dietary guidance.”

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