Colorectal cancer, or commonly known as colon cancer, is a type of cancer that grows in your colon, the last part of your intestine. Lately, there has been more awareness regarding colorectal cancer (CRC). Especially after the death of the "Black Panther" star Chadwick Boseman, which has put a spotlight on colorectal cancer that's on the rise amongst millennials.
According to a 2018 study, "Colorectal cancer is the third most deadly and fourth most commonly diagnosed cancer in the world." (1) And it is concerning because the incidence rate of colorectal cancer increases among 20-49 years of age. (2) Though many think our genes play a more significant role, the research found something different! Only 5-10% of cancer occurs because of your genes, and 90-95% resulted from your lifestyle, which includes your diet.
So, let's elaborate on what these environmental factors are from:
1. 30-35% is our diet
2. 25-30% is tobacco
3. 15-20% is infections
4. 10-20% is obesity
5. 4-6% is alcohol and others. (3)
If you look at the number, our diet is the biggest factor that plays a role in cancer, including colorectal cancer! So what do we know so far the link between diet and colorectal cancer?
Many of the long epidemiological studies have found again and again that "a dietary pattern high in fruits and vegetables and low in meats and sweets is protective against CRC (Colorectal Cancer) risk." (4) A UK study in 2020 found "consuming an average of 76 g/day of red and processed meat compared with 21 g/day had a 20% higher risk of colorectal cancer, while alcohol was associated with an 8% higher risk per 10 g/day higher intake." (5)
But how can fruit and vegetables protect us from colorectal cancer? It's because of the fiber! Well, when we eat fiber, our gut microbiota in our colon will fermentate them into Short Chain Fatty Acids (SCFAs) that are anti-carcinogenic in nature, which means they fight substances that can cause cancer. Secondly, fiber can help bulk up the stool in the intestine, so it lowers the chance for carcinogenic compounds to touch your colon's lining. (6)
On average, vegans are more often going to the bathroom than those who consume meat (7), your feces' transit time in the large intestine is shorter, decreasing the risk of colorectal cancer. In comparison, those who are constipated have a higher risk of colorectal cancer. (8)
While decreasing your meat consumption can lower the risk of getting colorectal cancer. Your low physical activity, high caloric intake from fat (such as fried food), obesity, and high alcohol intake are also other risk factors that we need to pay attention to prevent colorectal cancer comprehensively!