Colon Cancer- What is it, and Dietary Prevention

March is colon cancer awareness month! Many people are aware that cancer is one of the leading causes of death in the United States… but what really causes colon cancer, and how can it be prevented?

There is a wide variety of potential risk factors for colon cancer; however, the exact cause of colon cancer is the same as other cancers: mutation of genes making cells replicate uncontrollably. Some of these risk factors include older age, the presence of inflammatory intestinal disease, genetic factors, low fiber and high fat diet, sedentary lifestyle, diabetes, and even obesity. Smoking, alcohol, and radiation therapy are some associated factors that can increase the chance of an individual developing colon cancer.

Many cases of colon cancer can be 90%-95% due to environmental factors, while only the remaining small percent is due to genetic factors. Therefore, this means that colon cancer has a large potential to be prevented with changes in environmental factors like diet, exercise, environmental toxins, stress, and others.

What are the Symptoms of Colon Cancer?

Like the causes of this disease, there are also a variety of potential symptoms that colon cancer may manifest. Symptoms of concern may be persistent change in bowel habits including diarrhea or constipation, pain, blood in the stool, discomfort and gas, and feeling the bowel may not empty completely. Weakness and fatigue as well as unexplained weight loss can be other symptoms in combination that can indicate potential colon cancer.

Colon Cancer and the Human Microbiome

The area of research into the microbiome of bacteria that live in our bodies - especially our gut - is expanding significantly. We are coming to understand even more about the role of the microbiome in many diseases, colon cancer included.

In fact, the “good bacteria” that reside in the large intestine may help with renewing and maintaining the cells that make up the lining of the gut, metabolizing potential carcinogens, and even producing compounds that suppress cancer. However, these protective factors depend heavily on diet!

The bacteria that proliferate in the colon depend on what feeds them - which is what we feed ourselves! It appears in the research that individuals who eat heavier red meat or processed meat diets produce more carcinogenic chemicals, such as N-nitroso compounds, Hydrogen sulphide, and deoxycholic acid. These carcinogens are formed when the bacteria in the gut metabolizes compounds from a heavy meat and processed meat diet, increasing the risk for colon cancer.

Dietary Reasons for Colon Cancer

Many people have heard before that a “healthy diet” can help prevent cancers and many other health effects. Research conducted on diet and cancer has become essential as we realize that most chronic diseases of our time are due to environment and lifestyle choices. It all starts with diet!

As cited in multiple studies, it seems that a higher fat and lower fiber diet has been associated with colon cancer, as well as predisposition for inflammatory illness. A diet higher in processed meats is also associated with an increased risk for colon cancer, and many other studies have corroborated this information.

What are Good Dietary Choices to Prevent Colon Cancer?

What is a “healthy diet”? For colon cancer, a plant-based diet has been associated with a reduced risk for cancer. Specifically, whole foods high in nutrients and fiber and minimally processed foods are optimal. Though “healthy diets” can vary from person to person, the consensus for colon cancer appears that plant-based diets are far superior to the classic American diet, high in processed foods, meats, and fat, while excluding fiber.

There has been some evidence that berries, plums, pomegranates, cruciferous veggies, tomatoes, garlic, turmeric, ginger, soy , whole grains, and mushrooms have been able to manage and even help prevent colon cancer. Each of these types of foods contains different types of phytochemicals as well as fiber. Furthermore, these foods promote gut health and prevent the development of colon cancer, prevent carcinogens from causing DNA damage, and inhibit the growth of tumors even if they start by inducing apoptosis (cell death).

In general, a higher intake of vegetables and whole grains is inversely associated with colon cancer, meaning that it potentially decreases the risk of colon cancer. Also, it has been seen that higher levels of refined grains was associated with an increase in colon cancer.

You may be wondering, what foods should I include in my diet to help reduce inflammation, prevent colon cancer, and promote gut health? Here are some specific foods and micronutrients to include in your diet to do just that:


Ginger contains shogaols, which are organic molecules that regulate metabolic pathways and help with cell death to prevent cancer before it occurs. They are also more effective in killing cancer cells rather than normal cells, which is beneficial for fighting cancer in the body.


The organosulfur compounds and the flavonoids in garlic have been shown in recent years to help prevent colon cancer. They may help reduce formation of cancer in animal models! Additionally, they have been found to activate enzymes, convert carcinogens into non-toxic chemicals, and activate enzymes that regulate the cell cycle to prevent it from getting out of control.


Although scientists are still researching the exact mechanism by which they prevent and help with colon cancer, consumption of whole berries has been shown to help decrease inflammation and provide antioxidant protections for the cells in the gut.

Cruciferous Vegetables

This category of vegetables (including broccoli, brussel sprouts, cabbage, cauliflower, collard greens, kale, kohlarabi, mustard, rutabaga, turnips, bok choy, and Chinese cabbage) have sulfur-containing compounds that synergistically prevent DNA damage, as well as providing many other vitamins and minerals. These sulfur-containing compounds such as sulforaphane (present in most cruciferous veggies but mostly broccoli), and salicylates (present in many plants but in higher amounts in cruciferous vegetables) have both been associated with decreased carcinogenesis and tumor growth.


Tomatoes and the lycopene in tomatoes can help decrease the insulin-like-growth factors in colon cancer patients. High levels of Insulin-like-growth factors in the blood can be considered risk factors for colon cancer.

Calcium Rich Plant Foods

Recent data shows that dietary calcium is also very important in preventing colon cancer. There is data to suggest that low calcium in the body and in the diet can allow for the growth of tumors, specifically gastric and colon tumors in the body. The cells in the body use calcium for intra-cellular signaling, and variation in those signals can allow and possibly cause the growth of tumors. The calcium signal is used to tell cancerous cells to “die” in order to prevent cancer from spreading, but when calcium is depleted, this signal may be depleted allowing the tumors to grow.

There is a significant amount of calcium in broccoli, collard greens, spinach, kale, other greens, as well as butternut and acorn squash. Cruciferous vegetables are a great source of sulfur-containing anticancer compounds, as well as calcium! Talk about bang for your buck!

How can the Gut Microbiome Help Prevent Colon Cancer?

Though consuming processed meat compounds can interact with the gut bacteria, it’s shown that taking care and maintaining a healthy microbiome can help to prevent colon cancer. More importantly, there are certain plant-based compounds that have been seen to help prevent colon cancer as shown in the section above.

The complex carbohydrates that are found in whole-plant foods allow the production of short-chain fatty acids like butyrate, which promotes healthy metabolism and energy of the cells that line the gut. The idea is to encourage the gut bacteria to make butyrate with certain foods, such as legumes, rolled oats, cooked rice and potatoes, plantain flour, and under ripe bananas.

Polyphenols are compounds found in plants that are able to mediate cell events as well as prevent cancer from occuring. Cruciferous vegetables (kale, radhies, rutabaga, turnips, and arugula) as well as Brassica vegetables (broccoli, cabbage, cauliflower, or collard greens) are good choices for polyphenols.

Dietary fiber is composed of soluble and insoluble carbohydrates in plants. It does not get digested in the small intestine, but rather moves on to the large intestine to “feed” the good bacteria that live there. Consuming foods high in dietary fiber such as pears, strawberries, avocados, bananas, carrots, beets, leafy greens, cruciferous vegetables, and lentils can feed the “good bacteria”, promoting a healthy microbiome that will prevent colon cancer.

What Can You Do to Help Prevent Colon Cancer?

  1. Make sure to include high fiber foods in your diet!

  2. Eat a variety of fruits and vegetables-- particularly cruciferous vegetables, colorful fruits, bitter fruits and vegetables, and lots of legumes.

  3. Be wary of eating too much processed food, mainly processed meats!

  4. Colon cancer screenings are a great way to ensure that this disease is caught early or prevented! Especially if you are over the age of 45, we encourage you to begin your screening.

  5. Work with a Registered Dietitian to determine the dietary protocol that is right for you to prevent or manage your symptoms (gas, bloating, high blood pressure, etc). Get started today with no commitment.

Our “Good-Gut A-Z” book offers hundreds of recipes to inspire your next meal! Be sure to check it out here to get your own copy and make trying new foods easier for you! We also have recipe blogs that can be found on our website which may help inspire some dishes to Celebrate a World of Flavors for National Nutrition Month.

Heal with each meal!

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