Vegans and Colon Cancer Risk

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A vegan is not the same thing as a vegetarian. A vegan, pronounced vee-ghan, is a person who does not use or ingest any product from an animal source. This includes cosmetics, lotions, clothing and all food sources. True vegans enjoy a varied diet of plant-based foods such as fruits, vegetables, legumes and grains.


One reason a vegan diet may reduce colon cancer risk is due to the plant chemicals, known as phytochemicals, that are abundant in this diet.

Natural plant foods contain special chemicals that give them vibrant colors, resistance to disease, and health. When we eat plant foods close to (or in) their natural state, we are also ingesting the phytochemicals that kept the plant healthy before it was harvested. Some common phytochemicals include:

  • Carotenoids – Found in orange and yellow fruits and vegetables such as carrots, sweet potatoes, and peppers
  • Resveratrol – Found in grapes, berries, and wine
  • Soy isoflavones – Found in soybeans and soy products, like tofu
  • Flavonoids – Found in teas, fruits, vegetables and herbs


A true vegan abstains from all dairy including milk and cheese, which are excellent sources of calcium. Calcium is inarguably a vital mineral -- we need it to support our bones and our muscular health. Researchers are working to establish a link between a calcium-rich diet and decreased instance of colon polyps and colon cancer.

Vegans can obtain plenty of natural calcium in their diet through proper planning and by eating a wide array of plant foods. Some natural sources of calcium include:

  • Dark green leafy vegetables, such as kale or spinach
  • Broccoli
  • Almonds
  • Soy products like soy milk or tofu


Omnivores may wonder how a plant-based diet can provide enough iron, which is freely found in meat products (most notably red meat).

Eating an abundance of red and processed meat has been linked to an increased risk of developing colon cancer. Natural plant foods as well as fortified foods (grains) are an excellent source of iron and include:

  • Chickpeas
  • Spinach
  • Raisins and prunes
  • Cashews


Animal products are not the only source of protein, which is needed to sustain energy, promote healing, and build healthy tissues such as muscle. Vegans can obtain adequate daily protein intake through plant-based sources including soy products, legumes, nuts, and grains.


It's speculated that one reason vegans have reduced cancer risk is the fact that this group of individuals tend to have lower body fat and cholesterol than the rest of the population. Although plant-based foods, such as olive oil, can provide fatty acids, they are not the fats that lead to high blood pressure, heart disease and stroke. As a whole, vegans have less incidence of all chronic diseases including diabetes.

Visit a Dietitian

The American Cancer Society encourages a visit with a registered dietician (RD) if you are considering a vegan diet.

Make sure that he or she has passed a national competency exam and is a registered professional. An RD can help you tailor your diet and nutritional needs to help reduce your risk of colon cancer, during cancer treatment or to reduce risk of recurrence after treatment. He or she can also help ensure you obtain all of the essential vitamins and minerals, such as vitamin B12, that may be tricky to sustain on a vegan diet.

If you have no interest in adopting a vegan lifestyle, there are many different types of vegetarian diets, which are believed easier to adopt, including:

  • Vegetarian –- enjoys a plant-based diet but uses animal products
  • Lacto-vegetarian -- may eat dairy products with the plant-based diet
  • Lacto-ovo-vegetarian -- may eat dairy and eggs along with plant-based diet
  • Flexitarian -- may eat small amounts of dairy, eggs, poultry or fish with plant-based diet

Regardless of which diet suits you, make sure to follow the American Cancer Society's dietary recommendations to reduce cancer risk, which include eating more vegetables, fruits, whole grains and decreasing the amount of red meat and alcohol you ingest.


American Cancer Society. (2006). American Cancer Society's Complete Guide to Colorectal Cancer. Clifton Fields, NE: American Cancer Society.

American Cancer Society. (n.d.).Vegetarianism

Linus Pauling Institute Micronutrient Research Center. (n.d.). Phytochemicals. 

Winston, J.C. (December 2010) Nutrition Concerns and Health Effects of Vegetarian Diets. Nutrition in Clinical Practice; 25. 

Vegan Action. (n.d.). Frequently Asked Questions.

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