How Your Diet Impacts Breast Cancer Risk

Do you ask yourself why you got cancer? Was it something you did, something you ate, the place you live or the jobs you’ve held? So many ways to blame yourself, and too often receive blame in the form of questioning from others, that some of it sticks.

Into this stew of self-blame comes more research showing that what we eat may matter in terms of a first diagnosis of breast cancer. “Modifiable risk factors”, things like diet, weight and exercise, don’t reach the level of importance in breast cancer risk of being a woman or other nonmodifiable risk factors, but they do offer opportunities to play an active role in your own health. When studies discussing these factors come out, I try to balance my appreciation for how our bodies work, and what we can do to make them work even better, with my dislike of how frequently they fail to directly mention that these modifiable behaviors are only one aspect of risk. They may not be meaningful for most people in terms of absolute risk, or how hard they can be to modify.

Still, there’s no getting around the fact that if you can avoid blaming yourself for consuming a diet that featured candy in a starring role, knowing that a better diet may reduce risk is a good thing. Moreover, there are many diet modifications out there like fasting, restricted eating, ketogenic, Mediterranean or paleo and each has implications for overall health, other illnesses, drug interactions and so on. If you’re considering “eating healthy”, talk to your oncologist first. In addition to understanding interactions with your treatment, they may be able to connect you to a nutritionist skilled in helping people with cancer make better food choices.

Ever since I took part in a midwestern study that involved increasing the number of vegetables and whole grain food I ate; I’ve maintained a more balanced diet. I still don’t say no to everything considered unhealthy, but it has been surprisingly easy to incorporate more foods associated with better health. With high-sugar and high-fat options all around me during the last couple months of the year coupled with the annual reckoning on January 1st of “doing better”, the results of a French study that found an association between breast cancer risk and diet really interest me. The research showed that the straightforward World Cancer Research Fund (WCRF) 2018 food-based dietary guidelines were associated with a lower risk of breast cancer, especially in postmenopausal women.

I say the guidelines are straightforward because, let’s be honest, they are recommendations we’ve seen before: Eat more whole grains, vegetables, fruit, and beans while limiting fast food, red and processed meat, and processed foods high in fat, starch, and/or sugar. It’s here that my personal experience on the study near my home comes in handy--limiting is oh-so-hard but is made much easier if you adhere to the first part since you’ll be less hungry and probably feel better if the main focus is on adding in healthy food.

They also found, specifically, that a diet with a higher glycemic load and foods with a glycemic index greater than 55 were associated with increased cancer risk, especially breast cancer. The word “associated” is important and far different than saying these foods or this diet caused cancer. As with “prevention” versus “risk reduction”, words matter here: An association means exactly what it says and does not claim that association caused the event. In addition, the study authors were quick to point out that more research is needed to definitively show that glycemic index and glycemic load are modifiable risk factors for primary prevention of breast cancer.

So, what is the glycemic index of food? Essentially, this is what is used to monitor your food if you are diabetic. As you might imagine, low glycemic foods include things like green vegetables, many fruits, and beans; medium glycemic foods include bananas and oat breakfast cereals; and high glycemic foods are white rice, white bread, and other processed foods. Finding foods below that 55 GI level shown in the study is not difficult--I’ve been using this glycemic index as a resource--and I am focused on rebalancing my diet for 2021 by emphasizing those foods.

I do not and will never blame myself for developing cancer, yet I understand that a healthy diet is one thing I can control that allows me to feel better every single day. And if it helps me reduce my risk for another cancer? Even better.