October 26, 2020

Can food affect cancer risk?

While food choices cannot prevent a breast cancer diagnosis, a nutritious diet and healthy lifestyle can help reduce risk

by Chelsea Jackle, RD

Did you know that 1 in 8 women in the United States will develop breast cancer during her lifetime? (1) These odds may seem grim, but you should also know that survivorship has increased over the past several decades. (2) Better early detection and treatment are part of this improved outlook, but another important piece to the survivorship puzzle is prevention.

In addition to regular self-breast exams, mammograms, and follow-ups with your doctor to detect cancer early, being aware of lifestyle and nutrition changes that reduce your breast cancer risk is key. While no food or diet can prevent any cancer, eating a nutritious diet and living a healthy lifestyle can give you a better chance of reducing your risk.

There are many different types of cancer, all involving a variety of tissues and areas of the body. These differences impact how the disease behaves and how risk factors will affect it. For example, breast tissue is sensitive to changes in hormone levels (like estrogen), and this is especially true in cancer. Tumor growth is often affected by hormone levels. As most ladies know, your hormone levels change throughout each stage of life (and even within a month). This information on hormones will come in handy later.

Researchers are always studying how our diets, activity levels, and lifestyles affect cancer risk and survivorship. One of the largest ongoing projects on this topic is the Continuous Update Project (also known as CUP) from the World Cancer Research Fund. After analyzing many studies and looking for the strongest evidence available, the experts involved in this project identified a list of key factors that can impact your overall cancer risk. (2)

Foods to Include to Reduce Cancer Risk

Fruits and Vegetables

We’ve all heard that we should be eating more fruits and vegetables, but it may help to understand why experts emphasize the recommendation, especially when it comes to cancer risk.

Eating non-starchy vegetables can decrease the risk of a specific kind of breast cancer called ER- (or estrogen-receptor-negative). (2) Non-starchy vegetables include broccoli, cauliflower, cabbage, tomatoes, asparagus, green beans, brussels sprouts, leafy greens, onions, and so many more!

Fruits, vegetables, and other plant foods like whole grains and beans contain special compounds called phytochemicals. These compounds have some long, fancy-sounding names (glucosinolates, isoflavones, and polyphenols… oh my!), but what you really need to know is that different foods have different amounts of phytochemicals, and they all play different roles, which makes it important to mix up the plant foods you eat. When you eat a variety of foods you get a variety of cancer-fighting phytochemicals.

According to the CUP research, an important family of phytochemical for reducing your breast cancer risk is the carotenoids. (2) If you’re thinking to yourself, “that word kind of reminds me of carrots,” you’re right! Carotenoids are found in carrots, but they are also found in other fruits and vegetables like cooked tomatoes, broccoli, leafy greens, winter squash, sweet potatoes, watermelon, apricots, oranges, and cantaloupe.

Soy Foods

Soy always seems to stir up controversy. Does it help? Does it hurt? According to the CUP project, breast cancer survivors who ate soy foods saw better survival rates!

The controversy around soy has to do with phytochemicals in soy called isoflavones, which are plant forms of the hormone estrogen. (See, I told you hormones were going to come up again!) Since high estrogen levels in the body have been linked to a higher risk of breast cancer, some believe that the plant estrogen in soy is harmful. Some of this belief also comes from studies where rats were given very high doses of isoflavones and saw increased cancer rates.

However, the isoflavone levels we get from real food are much smaller than this, and humans are not the same as rats! Current evidence in humans has not shown a link between soy foods and breast cancer risk. (3) Generally, 1-3 servings from whole food sources like tofu, edamame, miso, tempeh, and soy milk is recommended.

Calcium-Rich Foods

The CUP project concluded that diets rich in calcium decrease breast cancer risk. (2) High-calcium foods include dairy products like milk, yogurt, and cheese, as well as fortified non-dairy alternatives. This research project also found that dairy intake can reduce the risk of pre-menopausal breast cancer. (2)

Other Lifestyle Modifications to Consider

Limit or Abstain from Alcohol

Consuming alcohol increases breast cancer risk as well as the risk for other cancers (colorectal, stomach, liver). The risk increases the more someone drinks. (2)

Maintain a Healthy Weight

Being in the overweight or obese categories for Body Mass Index (BMI, which can be used to screen for health problems, but in itself is not diagnostic of an individual’s health) decreases the risk of pre-menopausal breast cancer, but being in these weight categories during adulthood can increase the risk of post-menopausal breast cancer. Weight gain that happens in adulthood can also be a risk factor. (2) The key here is maintaining a healthy weight long-term.

Include Physical Activity

Evidence strongly suggests that vigorous physical activity (any activity that elevates your heart rate to 70–80% of your maximum heartrate) can decrease your risk of breast cancer, but any amount of physical activity can be helpful and may also reduce your cancer risk. (2, 4)

Key Takeaways

  • Eat non-starchy vegetables and a variety of plant-based foods
  • Include fruit and vegetables that contain carotenoids
  • Include calcium-rich foods like dairy or dairy-alternatives
  • Limit or exclude alcoholic beverages
  • Maintain a healthy weight
  • Stay active and include vigorous physical activity if possible

Following the World Cancer Research Fund guidelines has been shown to lower the risk of developing many cancers, including breast cancer. (5) Knowing these guidelines is one thing, but implementing them can be a challenge. Our team of registered dietitians is here to help you make lasting lifestyle changes to improve your health. Book a consultation today: https://www.gemcarewellness.com/nutravantage-request-a-call/ 


  1. https://www.nationalbreastcancer.org/breast-cancer-facts
  2. https://www.wcrf.org/dietandcancer/breast-cancer
  3. https://www.cancer.org/latest-news/soy-and-cancer-risk-our-experts-advice.html
  4. https://www.heart.org/en/healthy-living/fitness/fitness-basics/target-heart-rates
  5. https://academic.oup.com/ajcn/article/96/1/150/4571421