Tag Archive for: microbiome

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Gut Microbes Play an Important Role in Colorectal Cancer

By Emmanuel Olaniyan

Colorectal cancer (CRC) is one of the more common types of cancer and is the third largest cause of cancer-related deaths worldwide. According to the American Cancer Society, 153,020 new cases of CRC are expected to be detected throughout the U.S. in 2023, out of which 52,550 people will die from the disease. Considering these figures, it is important to raise public awareness about CRC in order to decrease the number of CRC-related deaths and new cases.

Several studies have researched the causes of CRC, and age, diet, genetics, and the gut microbiota have all been identified as risk factors in various ways. The gut microbiome, in particular, has been shown to play an important role in a number of diseases, and research has begun to focus heavily on its role in CRC. 

What is the Gut Microbiome?

The human gut microbiota refers to the trillions of microbes, such as bacteria, viruses, fungi, and others present in the human digestive tract. The microbiome is the environment they live in. Most microbes in the body are beneficial, but they may become harmful when out of balance.

The gut microbiota is crucial for the overall functioning of a healthy digestive system because it supports the absorption of energy from digested food, guards against pathogens, controls immunological response, and fortifies biochemical barriers of the intestine. However, when harmful bacteria enter the gastrointestinal tract through eating contaminated food or drinking contaminated water and cause infection, all of these advantageous activities could be disrupted.

Jaeho Kim and Heung Kyu Lee published a study in 2022 that found a strong association between gut microbiota and CRC. They came to the conclusion that the patients with CRC experienced dysbiosis (an imbalance in bacterial composition, changes in bacterial metabolic activities, or changes in bacteria distribution within the gut) more frequently than healthy individuals. Opportunistic infections were discovered to be more prevalent, and intestinal inflammation has been shown to be reduced along with the percentage of bacteria that produce butyrate, which is an essential component of our digestive system that reduces inflammation in the digestive tract, protects the brain and prevents cancer.

How Can We Maintain a Healthy Gut Microbiome?

Maintaining good hygiene and being mindful of the foods we eat can help keep our gut microbiota healthy. Studies have shown that eating more processed foods and a low intake of dietary fiber increase the risk of CRC. For this reason, it is recommended to consume fermented foods like cheese, soy sauce, vinegar, and yogurt as well as meals high in fiber like whole grains. It has been established that the bacteria present in these fermented foods are similar to those linked to gastrointestinal health. 

Finally, a decrease in processed food consumption and antibiotic use lowers the risk of developing CRC caused by gut microbes. 

 

Emmanuel Olaniyan is a Colorectal Cancer Prevention Intern with the Colon Cancer Foundation.

Image source: OpenClipart-Vectors from Pixabay

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Intestinal Bacteria: Biomarkers and Targets for Colorectal Cancer

By Parker Lynch

According to a study published in Cancer Biology & Medicine, the role of intestinal bacteria in the development of colorectal cancer (CRC) has been receiving a lot of attention in recent years. Various bacteria such as Fusobacterium nucleatum, Escherichia coli, Bacteroides fragilis, Enterococcus faecalis, and Salmonella sp., have been known to cause DNA damage. Additionally, these bacteria also help tumor cells evade the body’s immune response, creating a pro-inflammatory environment. The DNA damage and other hindrances upon one’s immune system and bodily function have been associated with the development and progression of CRC.

These bacteria can be useful biomarkers for CRC. Additionally, progress is being made in developing effective antibacterial therapies, which could prove useful in the treatment of CRC.

Parker Lynch is a Colorectal Cancer Prevention Intern with the Colon Cancer Foundation.

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Ultra-Processed Foods a Risk Factor for Colorectal Cancer

Diet has been recognized as an important modifiable risk factor for colorectal cancer (CRC). In particular, diets consisting of high fats and carbohydrates, such as red and processed meats, are considered high-risk. Now, a large-scale cohort study among U.S. residents has revealed that high consumption of ultra-processed foods might increase CRC risk in men—the third most diagnosed cancer in the U.S.. 

For the past two decades, researchers have witnessed a significant increase in the consumption of ultra-processed foods, industrial ready-to-eat or ready-to-heat products high in refined sugars, refined starch, and trans fats. Ultra-processed foods currently contribute to 57% of the total daily calories consumed by American adults. A growing pool of evidence suggests that ultra-processed foods increase CRC risk by altering the composition and diversity of gut microbiota and increasing the risk of obesity.  Some examples of these foods include bread and rolls, breakfast bars and cereals, hotdogs and other processed meats, packaged sweet snacks and desserts, jams and jellies, and condiments, among other things.

The above-mentioned study analyzed responses from over 200,000 participants—159,907 women from the Nurses’ Health Study (1986-2015) and 46,341 men from the Health Professionals Follow-up Study (1986-2014)—across three large prospective studies in the U.S. that assessed dietary intake. The follow-up period was between 24-28 years. At the time of study enrollment, none of the participants had any cancer diagnoses. Information on dietary intake, demographic characteristics, lifestyle factors, and medical conditions of the participants was obtained through food frequency questionnaires every four years. 

Of the 206,000 participants who were followed for more than 25 years, the research team documented 1,294 cases of CRC among men and 1,922 cases among women. The study findings indicated that those who consumed the highest amount of ultra-processed foods had a 29% higher risk of CRC compared to those with the lowest consumption. However, this was not observed among women. Among women, the risk of CRC was positively associated with higher consumption of ready-to-eat or ready-to-heat mixed dishes. In contrast, higher consumption of yogurt and dairy-based desserts was linked to a reduced risk of CRC among women. 

These findings support the importance of limiting certain types of ultra-processed foods for better health outcomes. Here are some additional resources on diet and lifestyle and how they can influence your colon health and overall wellness:

  1. Healthy Inside and Out: How Diet and Lifestyle Impact Colorectal Cancer
  2. Dietary Mindfulness Can Reduce the Risk of Colorectal Cancer
  3. Diet and Nutrition to Prevent Colon Cancer

 

Kitty Chiu is a Colorectal Cancer Prevention Intern with the Colon Cancer Foundation.

Image credit: Tim Toomey on Unsplash

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