The ongoing study that began in 2002 found vegetarians had a 22% lower risk for all colorectal cancers than carnivores (19% lower risk for colon cancer; 29% lower risk for rectal cancer).
Vegans had a 16% lower risk of colorectal cancer; there was an 18% lower risk for lacto-ovo (eat milk and eggs) vegetarians; 43% less for pesco-vegetarians (eat fish); and 8% less in semi-vegetarians (eat some meat), according to the Loma Linda University Health study.
However the overall cancer cases were low given the sample of nearly 78,000 Seventh-day Adventists. From that sample there were 380 cases of colon cancer and 110 cases of rectal cancer.
JAMA Intern Med.
Published online March 09, 2015. doi:10.1001/jamainternmed.2015.59
‘Vegetarian Dietary Patterns and the Risk of Colorectal Cancers’
Authors: Orlich MJ, Singh PN, Sabaté J, et al.