Colorectal cancer: plant-based diet can reduce risk by up to 22%

The study published this week involved 173,427 participants from various ethnic groups. The results, obtained after an average follow-up time of just over 19 years, revealed that men who ate a healthy plant-based diet had lower rates of colorectal cancer.

Women included in the study did not see the same benefit.

A total of 4,976 participants were found to have colorectal cancer. Further analysis divided the participants into a number of subgroups, including those who smoked and those who consumed alcohol, as well as by race and ethnicity to identify any additional patterns.

Principle results

• The team found that men who ate the healthiest plant-based foods had a 22% reduced risk of developing colorectal cancer.
• The difference in male health benefits was greater in Japanese-American, Native Hawaiian, and white populations as opposed to those identified as African-American and Latino.
• Poor diet increased the risk of cancer that was in the rectum rather than on either side of the colon

The researchers used a set of data tools that allowed them to assess the quality of plant-based foods as well as animal-based products.

Mona S. Jhaveri, PhD., founder and director of Music Beats Cancer, says the study had some limitations, but it has significant value in researching ways to prevent cancer.

“I think what excites me the most about this study is that it’s actually a method of [prevention,]said Jhaveri. “And what I see in my world, in the biotech world. Either: we focus a lot on cures and treatments. And what the public is really looking for, in my opinion, are ways to prevent or screen for cancer.

Assistant Clinical Professor in the Department of Nutrition and Exercise Physiology at Washington State University, Lisa Heneghen (MPH, RDN, CSO, CNSC), told Healthline that the ability to assess the quality of Plant-based food was essential because all plant-based diets are healthy.

“We can say, ‘Eat this type of diet,’ but how people interpret or implement it can mean a lot of different things,” Heneghen said. Consuming “the fuller version of this plant food and the purer version of this plant food, so unprocessed, actually showed a reduced risk of colorectal cancer incidents, which is quite interesting.”

The study found that women did not see the same benefits as men. The researchers hypothesized that women had healthier diets than men in general. They suggest that because women were consuming a healthier diet from a baseline, the changes for those eating more healthy foods would be less drastic than for men.

The study contains a number of limitations identified by the researchers, including the possible need for further investigation regarding the impact of dairy and fish consumption on colorectal cancer risk.

Jhaveri said getting the public to drastically change their diets is an uphill battle, as food companies spend millions each year marketing less healthy foods.

“We’ve known these things forever,” Jhaveri said. “But yet, putting this into public practice is extremely difficult because I think disease experts are dealing with a lot of marketing… it’s becoming a really difficult thing to put in place, and we need better ways to do it.

Heneghen, whose previous roles included working at cancer centers, says few centers employ dieticians who could help people understand their cancer risk in relation to their diet.

“It’s hard for cancer centers to really afford the cost of employing dietitians when there isn’t a huge return on billing [from insurance companies,] and so that’s a big hurdle,” Heneghen said. “They start charging patients for their time with a dietician, and then it’s a huge financial barrier and patients don’t want to pay out of pocket to see a dietician.”