Cancer + Nutrition: Q&A with Amanda Bontempo, Oncology Dietition

Nadja Pinnavaia Ph.D.
Feb 26 · 8 min read

We’ve discussed the anti-cancer diet (or should we say lifestyle) as well as sugar’s connection to cancer and the benefits of antioxidants for cancer prevention. There is no question that the foods we eat impact our immunity, which can put our body in the best possible shape to fight cancer.

That’s why we sat down with Amanda Bontempo, a registered dietitian board certified in oncology nutrition,to pick her brain about all things food and cancer. As an oncology dietitian at NYU Langone Medical Center, Amanda knows her stuff and answered some of our burning questions.

Could you tell us what you do for a living and how you got into this field?
I am a dietitian, board certified in oncology nutrition. I am privileged to work with people with cancer across the treatment spectrum. Meaning, those who have been newly diagnosed through survivorship; those with early stage curable diseases to those who have incurable advanced disease. I help support patients feel and live their healthiest and empower them to adopt healthy nutrition and wellness lifestyles. A cancer diagnosis is shocking and the area of food and nutrition surrounding it is marred by conflicting messages and misinformation. I have found it deeply satisfying to help patients and families assume agency again surrounding food decisions after having so often lost it to the fear that only a cancer diagnosis can case.

What’s the most surprising thing about the link between nutrition + cancer (or other illnesses for that matter)?
The human body and its relationship to our environment is so fascinatingly complex that it’s easy to think that little things (I’m looking at you mini muffin) don’t make a difference. We all live with internalized myths that undermine our determination to fight diseases like diabetes, heart disease, and cancer among many others. We hear it all the time: “it runs in my family,” or “I have bad genes,” or “it was just a matter of time.” One of the most surprising things to me is how much power we truly have as individuals to nourish and strengthen our bodies and our environments. The American Institute for Cancer Research reports that simple changes in nutrition and lifestyle can prevent 30–40 percent of cancers. That is so beautifully wild to me. It means that we do have the power to act.

Do you feel as though you often have to defend nutrition and how it affects cancer?
Especially surrounding cancer, there is so much vulnerability to misinformation that it can almost become a dissonance. And as our realities are increasingly based on information consumed in the palm of our hands it’s easy to create a personalized, almost curated bubble to suit what we think we already know or to suit how we think the world looks. It’s like there’s a buffet of information where we get to pick and choose our ‘truth.’ This is, very simply, confirmation bias and we participate in it unknowingly daily. I think that it is imperative to not appeal to the lowest common denominator in an attempt to appeal to the masses. As professionals, we should instead raise it. We should not allow things that are so patently and objectively true (or false!) to be blithely dismissed.

What’s your favorite nutrition book?
One of my favorite food books is The Omnivore’s Dilemma by the remarkably clear-headed Michael Pollan. The book is an easy-to-read exploration of the food chain. Pollan will have you thinking about where food comes from just a little differently. It’s definitely worth the read. In addition to Pollan’s other books, I loved What to Eat by Marion Nestle; Food Matters by Mark Bittman; Foodist by Darya Pino Rose; and not nutrition-related but cancer-related is The Emperor of all Maladies by Siddhartha Mukherjee which explores the history of cancer and cancer treatments.

What foods do you recommend eating for cancer prevention? Is there one diet that is best at fighting cancer?
I love this question. I really do not think that there is just one diet that is best at fighting cancer. I think traditional diets of many different regions from Okinawa to Sardinia to Nicoya and Icaria that follow the same basic tenets that make up the foundation of a strong lifestyle. These include eating whole foods like vegetables, fruits, lentils, beans, nuts, seeds, whole grains and healthy fats; near avoidance of processed foods; minimal animal products; and physical activity. The standard American diet has strayed far from this and instead relies on heavily processed foods devoid of any virtue despite the label claims; large amounts of animal products; and a sedentary lifestyle. Returning to a healthy and natural way of eating is often not sexy enough to capture the buy-in of people who are too often seduced by label claims of ‘low fat’ or ‘low sugar’ or ‘heart healthy’ and the like. So if a simple, healthy diet of whole foods is packaged and glossed up, it would be an ‘anti-inflammatory’ diet. For more information on what to eat to prevent cancer, check out the AICR website here.

Are there foods that I should be avoiding completely?
The only foods that should be avoided completely are those that cause exacerbated symptoms due to the disease or the treatment. Those primary concerns aside, there is no food that needs to be avoided completely. I strongly believe that we must work hard to shift our reliance away from processed foods, which are often full of unhealthy trans-fats, added sugars, processed starches, sodium, chemicals and other fillers. Beyond that, it’s the dose that makes the poison. If it’s a birthday or a celebration, then please enjoy a piece a cake or pizza or your indulgence du jour. A healthy relationship with food would be, for example, enjoying a real home-made brownie or a cheese platter on occasion rather than having a processed, fat-free brownie marketed as a healthy snack or a fat-free piece of sad rubbery cheese every day. This idea of ‘treat training’ is so often under-recognized and helps us stave off the temptation of seeing foods as black and white. This is the idea that we transform something guilt-ridden into something enjoyable so that you can have your treat and health too.

Are there supplements I should be taking to reduce my cancer risk?
Some patients who are unable to eat healthy, balanced diet due to the disease or the treatment effects, may require a supplement. For most people, however, supplements represent how health and medicine have been taken over by consumerism. Why is it that we believe in the magic power of a pill to heal? There is no one food or supplement or tincture that can cure cancer. It’s important to note that supplement manufacturers do not need to demonstrate purity, efficacy or consistency prior to bringing a product to market. This is kind of bananas when you think about it. Labels imply illness prevention, energy or immunity boosting powers and other claims yet manufactures simply do not need to show any of it! It’s imperative to note that many natural and innocuous seeming supplements also have potential to reduce the efficacy of antineoplastic treatments. So please, disclose all supplements to your oncologist or oncology dietitian so we can ensure that they’re safe. Lastly, I think that we must maintain perspective and remember that supplements are meant to supplement and never to replace a healthy diet. Sorry, you can’t pop a few pills and fall off the healthy diet wagon. It’s important to continue to eat a healthy, varied diet.

If I have had cancer, can a healthy diet reduce the risk of cancer coming back?
Cancer is not one disease but hundreds of diseases. Research absolutely supports that a healthy diet reduces the risk of some cancers recurring more than others. Either way, we know for a fact that diet helps prevent other chronic diseases like diabetes and heart disease. Remember that we are not a compilation of systems or diseases. In a lot of ways, these chronic disease and cancer share common roots and all require healthy lifestyles similarly.

I had breast cancer. Should I be avoiding soy?
Soy and other phytoestrogens like flax might sound scary to women with estrogen-sensitive breast cancer because they share that word, ‘estrogen.’ As a result, old science made us fearful of eating soy foods. Turns out, that whole soy foods are not only safe but they’re probably healthy especially for women with estrogen-sensitive cancer. Think of it this way: if every cancer cell is a store with a parking lot surrounding it, then whole soy foods are the cars that jam up the lot so that real circulating estrogen cannot get in and cause growth. It’s unfortunate that the lore about soy from yesteryear permeate even our doctors’ limited nutrition knowledge despite exciting and promising research, which started most seminally with the Shanghai Women’s study from the mid-nineties. Healthy whole soy foods include tofu, edamame, soy nuts, miso, tempeh, soy sauce and others. Processed soy foods like soy-based sausages and cheese and other faux-meat analogs are much less healthy. They are much less healthy, not because they feed cancer in any way but because they’re processed foods that higher in sodium and other junk. It’s okay to enjoy these on occasion but it’s important not to confuse it with healthy whole soy foods, which can be enjoyed daily without fear.

Do artificial sweeteners cause cancer?
Our quest for guiltless sweetness has led to pervasive use of artificial sugars in the food supply. They’re used in weight loss and “diet” products; items marketed as being healthy or for people with diabetes. It’s not always the ubiquitous yellow, blue or pink packets either. There are other sweeteners that are used in food production that are not always recognizable like acesulfame-k or neotame. Artificial sweeteners have been the subject of scrutiny for decades. Critics cite them as causing a variety of health problems including cancer. This is largely because studies from the 1970s linked saccharin to bladder cancer in rats causing the package to cause a warning label that it may be hazardous to health. However, according to the National Cancer Institute and others, this research cannot be translated to humans, which has been confirmed in numerous studies. So no, they don’t cause cancer but there’s a catch. Research including studies from the National Institute of Health, the Mayo Clinic, Harvard and the San Antonio Heart study show us that artificial sweeteners significantly increase the risk of metabolic syndrome, diabetes, increased appetite, less satisfaction, cravings, overeating, even binging behavior, weight gain and difficulty losing weight, a condition called insulin resistance or glucose intolerance and even changes in our but microbiome and immunity. Not to mention the fact that they are just so sweet that it shifts our palate to this hyper-intensity of sweet, limiting tolerance of all else so fruit just doesn’t taste sweet enough and veggies can be downright gross. So does do artificial sweeteners cause cancer? No, but that’s the wrong question to ask. Are they healthy? Nope. Sounds like a wolf in sheep’s clothing to me.

For more from Amanda Bontempo, follow her on Instagram at @AmandaBonBon.

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