Veganism and Cancer: What Should You Know?

6 min reading time

It’s expected that by the year 2030, there will be 21.7 million cases of cancer around the world, up from 14.1 million cases in 2012. Cancer is the most dreaded of all chronic diseases and is currently the second largest cause of death globally. 

Surprisingly, only 5 to 10 percent of cancers are determined by genetics. The remaining 90 to 95 percent are a product of the environment. 

Strong evidence shows that diet is actually a major environmental factor, accounting for 30 to 35 percent of all cancers!

This article will review the scientific evidence on the connections between veganism and cancer

What is cancer?

Cancer is a disease in which some of the body’s cells grow uncontrollably. When these problematic cells continue to divide instead of dying out, they force out healthy cells. 

Cancerous tumors, or masses of problematic cells, spread into, or invade, nearby tissues. They can also travel to other places in the body to form new tumors (metastasis).

The spread of unhealthy cells can lead to cancer. 


Causes of cancer

Causes of cancer include environmental factors, lifestyle behaviors, and genetics. Less than 10 percent of cancer cases are caused directly by genetics passed on by parents. 

Even when people do inherit genetic mutations that place them at a higher risk of developing cancer, adopting a healthy lifestyle can significantly reduce that risk. 

Cigarette-smoking is a major contributor to cancer risk, but it’s by no means the only lifestyle factor to play a significant role. Infections, obesity, alcohol consumption, stress, inadequate physical activity, exposure to radiation, and exposure to environmental contaminants are some of the factors that can increase cancer risk. 

Diet, however, is arguably the most vital factor for cancer risk. 

Based on strong scientific evidence, eating a plant-based diet rich in fruits, vegetables, whole grains, and beans may be one of the most powerful tools in cancer prevention. 

Foods linked to cancer

Red meat and cancer

In 2015, the World Health Organization classified processed meats as a carcinogen and red meat as a probable carcinogen, based on epidemiological studies on colorectal cancer.  


Since then, there has been evidence suggesting that red meat is linked to other cancers like those of the esophagus, lung, pancreas, and endometrium. 


Red meat and cancer are linked because cancer-causing compounds can be generated from heme iron found in red meat. Meat consumption is also associated with higher levels of IGF-1, a growth hormone linked to higher levels of cancer. 


The saturated fat present in meat products also promotes inflammation.


In fact, a large study in the International Journal of Cancer found that those who ate the most plant foods and least red meat and animal foods reduced their risk of cancer by 15 percent. 


There is no doubt that red meat intake and cancer are associated. In this way, veganism and avoidance of meat is one of the best ways to prevent cancer


All types of alcoholic drinks, including red wine, are linked with cancer. 

Studies have found a dose-response relationship, meaning the more alcohol a person drinks over time the higher the risk of developing cancer. 

Alcohol has been specifically associated with breast, colorectal, and esophageal cancers.

Highly processed foods

Consuming energy-dense processed foods and sugary drinks often replaces foods rich in antioxidants and other nutrients that may help reduce cancer risk.

Highly processed foods also contribute to weight gain, which is a risk factor for certain cancers. 

A large study out of the Harvard T.H. Chan School of Public Health examined many lifestyle factors related to cancer. They found that just eating a healthy diet alone high in vegetables, fruits, whole grains, unsaturated fats, and omega-3 fats and low in red and processed meats, trans fats, and sugar-sweetened beverages reduced the risk of dying from cancer by 30 percent.

Veganism is a great dietary pattern because it is balanced and rich in fruits, vegetables, whole grains, nuts, and beans. In this way, veganism and whole foods can reduce cancer risk.  

Can a plant-based diet reverse cancer? 

What if you already have cancer? Can a plant-based diet reverse cancer?

I’ve seen numerous success stories, testimonies, and anecdotes that report excellent responses in cancer patients who follow plant-based diets. Even though I’ve seen amazing results in some of my clients, this is not causative and doesn’t hold up against scientific research. 

Studies examining vegan diets in the treatment of cancer are rare. However, a 2020 study found that eating a low-fat diet rich in veggies and whole grains could help improve survival rates for breast cancer patients. 

Another study found that in colorectal cancer patients, for every 5 grams of additional fiber consumption per day, there was an 18 percent lower risk of death from cancer. 

So overall, it cannot be concluded that a plant-based diet can reverse cancer, but there is compelling evidence that healthy plant-based eating patterns have a positive effect in cancer patients. 

Top 5 veganism and cancer tips

Based on the evidence currently available, veganism and plant-based eating plays a role in decreasing cancer risk. 

While it’s still too early to estimate the potential of vegan diets in cancer treatment, consuming a vegan diet does confer benefits and is a reasonable adjunct treatment to consider.

Here are my top 5 veganism and cancer tips:

  1. Include at least 8 servings of fruits and veggies per day, emphasizing all the colours of the rainbow and dark leafy greens (see my article on the benefits of greens)
  2. Aim for at least 35 grams of fiber per day
  3. Limit processed foods as much as you can
  4. Choose healthy fats like nuts, seeds, and avocados. Ensure you get enough Omega-3.
  5. Make water your drink of choice

Veganism and Cancer: What Should You Know?

There is strong evidence that veganism is the way to go in order to prevent cancer. If you are ready to make the shift towards a plant-based diet, a registered dietitian can support you. 

I suggest you start with gradual changes. Experimenting with meatless meals, trying beans, or adding new veggies to meals are great starting points. For more beginner vegan diet tips, check out my article.