Plant-Based Eating Reduces Colorectal Cancer Risk in Men by 22 Percent

It is now clearly known that plant-based eating is much healthier for the gastrointestinal system. Diet becomes even more important when it comes to the large intestine.

The human large intestine, made up of 2 continuous structures called the colon and rectum, is much more susceptible to cancer than the small intestine. Yet the small intestine is 7-8 metres long, 5 times the length of the 1.5-metre large intestine. The main factors determining the difference in disease risk appear to be the amount of toxic/harmful substances they encounter and the duration of exposure. Toxic substances in food become more concentrated as digestion progresses towards the large intestine. Plant-based foods consumed by humans contain far fewer toxic substances than animal products and processed foods.

A Study Involving 170 Thousand People  

A study of approximately 80 thousand men found that those whose diets were the most plant-based had a 22% lower risk of colorectal cancer than those whose diets were the least plant-based. The same study included 93 thousand women, but no such association was found in women.

Jihye Kim, the corresponding author of this study of people in the US, said, ‘’Colorectal (colon and rectum = large intestine) cancer is the third most common cancer worldwide. Over a lifetime, one in every 23 men and one in every 25 women is at risk of developing colorectal cancer’’.

In the study, people were asked how often they consumed specific foods and drinks from a list of more than 180 items, and about their portion sizes.

Food groups were classified as healthy plant foods (whole grains, fruit, vegetables, vegetable oils, nuts and pulses such as lentils and chickpeas), less healthy plant foods (refined grains, fruit juices, potatoes and added sugars), and animal foods (animal fats, dairy products, eggs, fish or seafood, and meat).

Kim said, “We think that substances in foods such as fruit, vegetables and whole grains may contribute to reducing colorectal cancer risk by suppressing chronic inflammation that could lead to cancer”. In addition to their rich fibre content, fruit and vegetables contain many different vitamins, minerals and antioxidants, which are micronutrients.

The association among men also varied by race and ethnicity. For example, the reduction in cancer risk was 20% among Japanese American men and 24% among white men. More research is needed into differences between ethnic groups.

The researchers also noted that, because of the study's “observational” nature, no conclusion could yet be drawn about a causal relationship between plant-based food intake and colorectal cancer risk.