Colorectal cancer is expected to cause almost 50,000 deaths in the US this year, making it the second leading cause of cancer death in the country. But in a new study, researchers say consuming a vegetarian diet could significantly lower the risk of developing the disease.
Study co-author Dr. Michael J. Orlich, of Lorna Linda University, CA, and colleagues publish their findings inJAMA Internal Medicine.
Colorectal cancer is a cancer that begins in either the colon or the rectum. It is a collective term used forcolon cancer and rectal cancer. According to the American Cancer Society, an individual has a 1 in 20 chance of developing the disease at some point in their lives.
While the death rate from colorectal cancer remains high, it has fallen over the past 20 years. This is primarily due to increased screening for the disease, allowing it to be detected earlier and making it easier to treat.
Treatment for colorectal cancer has also improved in recent years, which has led to better survival rates. There are now more than 1 million colorectal cancer survivors in the US.
While screening and treatment should remain an important focus for colorectal cancer, Dr. Orlich and colleagues say identifying risk factors for the disease is crucial for primary prevention. For their study, the team investigated dietary risk factors for colorectal cancer.
22% lower risk of colorectal cancer with vegetarian diet
Numerous studies have suggested that a diet high in red and processed meats can raise the risk of colorectal cancer, while a diet high in fruits, vegetables and whole grains has been associated with a reduced risk. To build on these findings, the team set out to see how consuming a vegetarian diet affected the risk of developing colorectal cancer.
The researchers analyzed 77,659 men and women who were recruited to the Adventist Health Study 2 (AHS-1) between 2002 and 2007.
All participants were required to complete a food frequency questionnaire and medical questionnaire at study baseline. Cancer incidence among participants was assessed until 2014 via computer-assisted record linkage with state cancer registries, as well as a follow-up medical questionnaire.
Over an average 7.3-year follow-up, 490 participants were diagnosed with colorectal cancer, of which 380 cases were colon cancer and 110 were rectal cancer.
The results of the study revealed that individuals who ate a vegetarian diet were at a 22% lower risk of colorectal cancer, with a 19% reduced risk of colon cancer and a 29% reduced risk of rectal cancer, compared with participants who did not follow a vegetarian diet.
Looking at the results by the type of vegetarian diet followed, the team found pescovegetarians (who eat fish) had a 49% lower risk of colorectal cancer, lacto-ovo vegetarians (who eat milk and eggs) had an 18% lower risk, vegans had a 16% reduced risk, and semi-vegetarians were 8% less likely to develop the disease.
The researchers say their findings appear consistent with previous studies associating consumption of red and processed meats with increased risk of colorectal cancer.
As such, they say that if the link between a vegetarian diet and reduced risk of colorectal cancer is found to be causal, following a vegetarian diet could be an important prevention strategy for the disease. The team adds:
"The evidence 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."
Last month, Medical News Today revealed that two new reports hail the vegan diet for increasing physical health and emotional well-being. One of the reports claimed the diet led to employees of an auto-insurance firm experiencing an average 10 Ib weight loss and a 13-point drop in "bad" cholesterol.
Written by Honor Whiteman