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FOOD + NUTRITION, LIVING WITH BREAST CANCER

5 Things You Need To Know About Intermittent Fasting and Breast Cancer

By Rethink Breast Cancer November 29 2019

Sure, Intermittent Fasting may be all the rage in Hollywood (after all Jennifer Aniston and Reese Witherspoon are reported fans) but that doesn’t mean it’s for everyone, especially if you’re facing a breast cancer diagnosis and/or treatment. With limited scientific information out there, it might be challenging to make an informed decision about whether IF is right for you. So, we spoke to some experts to help shed some light on IF.

 

WHAT EXACTLY IS INTERMITTENT FASTING (IF)?

Intermittent fasting is a dietary pattern that involves consuming little to no calories for an extended period of time. According to Jill Shainhouse, a naturopathic doctor who is trained in naturopathic oncology says the most popular fasting to eating ratio is 16:8. That means the fasting period should last around 16 hours followed by eight hours of normal caloric intake. The easiest way to do this is to finish eating by around 8 or 9 P.M., skip breakfast, and resume eating at 12 or 1 P.M. the following day.

 

ARE THERE STUDIES ON IF AND ITS EFFECT ON BREAST CANCER PATIENTS?

So far, only one human study has examined the link between prolonged nighttime fasting and the risk of breast cancer recurrence in 2413 women with early-stage breast cancer (but without diabetes),” says Leslie Beck, a registered dietician and nutritionist. Researchers found that women who fasted less than 13 hours each night were 36% more likely to have their breast cancer recur over the seven-year study, compared to women who fasted 13 hours or more. The women also had significantly lower blood levels of hemoglobin A1C, an indicator of blood glucose control. The findings suggest that prolonging the nightly fast but following a form of IF called early time-restricted eating (or circadian rhythm fasting) may help reduce breast cancer recurrence,” says Beck.

She explains that since our bodies are adapted to eat during the day and sleep at night; eating at abnormal times (e.g., late in the night) can cause misalignment with the body’s circadian rhythms. Circadian misalignment has been linked to an increased risk of many cancers, including an increased breast cancer risk among shift workers.

In terms of those undergoing chemo treatment, Jill Shainhouse says patients often ask about Dr. Valter Longo’s chemotherapy fasting protocols based on research that shows intermittent or short term fasting (up to 72 hours around chemotherapy) can decrease side effects of treatment while simultaneously increasing the efficacy of a wide variety of chemotherapeutic agents. “While more research needs to be completed in this area prior to making broad recommendations, it appears that fasting protocols are safe when used as an adjunct to chemotherapy in humans,” she says.

 

WHAT ARE THE BENEFITS OF INTERMITTENT FASTING?

It’s no secret that weight loss has been associated with IF. “There is ample research to demonstrate that when you fast, you improve insulin sensitivity, and regulate metabolism making this a helpful tool in weight management. There is also evidence that fasting may improve the gut microbiome, cellular repair and sleep quality,” says Shainhouse.

“If patients are struggling with their weight as a result of treatment or being jolted into menopause, I find that IF is beneficial in kickstarting a sluggish metabolism and treating insulin resistance.”

 

ARE THERE ANY NEGATIVE SIDE EFFECTS TO IF?

Intermittent fasting isn’t for everyone. “For many people, it can be a struggle to go for extended periods without food or eating very little,” says Beck. Side effects such as headache, fatigue and irritability have been reported though Beck says they usually diminish over time.

It’s also important to consider other issues a patient is prone to, such as hypoglycemia and syncopal (fainting) episodes. “Please pay attention to your body’s cues and consider medical advice from a healthcare professional prior to implementing any extreme changes to your current dietary habits,” advises Jill Shainhouse.  

When we’re going through a vulnerable and stressful experience like breast cancer diagnosis/treatment, it’s natural to want to do whatever you can to control the situation and show up for yourself in any way possible,” says Lauren Neuburger, a Holistic Nutritionist. She explains that it’s really important to note that fasting can cause more harm than good if a person is in a state of chronic stress. “When this happens, the body is in that fight or flight nervous system state and it will perceive the fast as a threat to its survival rather than use it as a tool for detoxification. And when this happens, fasting can cause a release of stress hormones and also insulin even when someone isn’t eating.

 

FINAL THOUGHTS ON IF AND BREAST CANCER

Fasting is just a tool when and if you need it, not the end all be all, says Neuburger. There are a lot of ways to support your body’s detoxification system through food that actually involve eating instead of fasting. “By partnering with your body and meeting yourself where you are at is the most effective way to support your body and your health as you journey through cancer treatment and beyond.” -By Hannah Ziegler and Tania Kwong

 


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