Can nightly fasting of at least 13 hours reduce the risk of breast cancer recurrence?


Women (and men) diagnosed with early stage breast cancer are constantly on the lookout for low cost, non-pharmacologic interventions they can incorporate in their everyday lives to stay healthy and help prevent a recurrence.

A study lead by Ruth E. Patterson, PhD, of the University of California, San Diego, investigated whether the length of nightly fasting predicted recurrence and mortality among women with early-stage breast cancer and, if so, whether it was associated with risk factors for poor outcomes, including glucose metabolism, inflammation, and weight gain.

The study collected data from 2,413 women with early stage breast cancer and who participated in the Women’s Healthy Eating and Living Study between 1995 and 2007. The study looked at breast cancer recurrence and new primary breast tumors with an average of 7.3 years follow up. Death from breast cancer or any cause was also looked at during an average of 11.4 years follow up. Average age for participants was 52.4 years and average fasting duration was 12.5 hours per night. Participants self reported their dietary data.

Dr Patterson and her group found that a nightly fast of less than 13 hours was associated with a higher risk for breast cancer recurrence compared with fasting 13 or more hours per night. Additionally, each two-hour increase in nightly fasting was associated with improved glucose metabolism (lower hemoglobin A1c) and a longer duration of nighttime sleeping. As an added bonus, the analysis also reported that fasting has the potential to possibly reduce the risk of type 2 diabetes and cardiovascular disease. The shorter fasting was not, however, associated with a higher risk of death from breast cancer or any other cause.

This idea of 13 hours nightly fasting is sometimes referred to as intermittent fasting. Timing your meals could be a simple strategy for breast cancer survivors to employ. For example, if you eat dinner at 7pm, you would wake up and have breakfast at 8am. While intermittent fasting shortens your eating window, it does not necessarily restrict calories. But it will curtail late-night snacking , which is a smart choice for anyone. The authors concluded that “Randomized trials are needed to adequately test whether prolonging the nightly fasting interval can reduce the risk of chronic disease.” Sign me up!

Source: JAMA Oncology, online edition, March 31, 2016

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