A feasibility study has found that a pattern of time-restricted eating in older breast cancer survivors reduces cardiovascular risk
Utilising time-restricted eating (TRE) in older breast cancer survivor patients with recognised cardiovascular risk factors, appears to reduce their overall risk, according to the findings of a feasibility study by researchers from the University of Toronto, Canada.
The World Health Organization has identified that globally in 2020 there were 2.3 million women diagnosed with breast cancer and which resulted in 685,000 deaths. Fortunately however, the overall 5-year breast cancer survival rate is 85% although this does depend upon the stage at which the cancer was detected and is less for those with later stage disease, for example, 1-year survival for those with stage 4 is only 66%.
Despite these high survival rates, it seems that breast survivors are at greater risk of cardiovascular-related mortality compared with those without cancer. In fact, a 2017 systematic review concluded that cardiovascular disease (CVD) is an important cause of death following breast cancer.
Consequently, strategies directed at reducing CVD risk among breast cancer survivors are likely to be highly beneficial. One such strategy which has attracted much attention in recent years is time-restricted eating (TRE), a form of intermittent fasting based on the circadian rhythm.
For example, one approach, 16:8, allows individuals to eat ad libitum but only during an 8-hour window, e.g., between 12 and 8 pm. TRE could help to reduce CVD risk and in a 2020 systematic review, the authors concluded that TRE is a promising therapeutic strategy for controlling weight and improving metabolic dysfunctions in those who are overweight or obese.
Given the elevated risk of CVD-related mortality among breast cancer survivors, the Canadian team wondered if TRE could reduce this risk, especially among those with pre-existing risk factors such as older age, being over-weight or obese and those who had completed a course of cardio-toxic chemotherapy such as anthracyclines, within 1 to 6 years.
The researchers enrolled a group of such women and asked them to eat as much as they wanted, but only between 12 and 8 pm and to only drink water, black tea/coffee outside of this feeding window, for a period of 8 weeks. During the study, participants were given access to behavioural support from a registered dietician.
The researchers calculated participants’ 10-year Framingham CVD risk and collected demographic and clinical data e.g., glucose and cholesterol levels as well as blood pressure, waist circumference, visceral adipose tissue (VAT) and whole body fat-free and fat mass.
Time-restricted eating and cardiovascular outcomes
A total of 22 participants with a mean age of 66 years and a mean body mass index (BMI) of 31 were included in the study. Fat-free mass did not change during the study period, although calorie intake was significantly reduced by a median of 450 kcal (p < 0.001).
At baseline, 68% of women were classed as cardio-metabolically unhealthy and this reduced to 53% at the end of the study.
The median Framingham CVD risk score reduced from 10.9% at baseline to 8.6% (p = 0.037), although modifiable factors in this score such as total cholesterol and systolic blood pressure were not significantly different. In addition, the mean BMI did not change whereas both VAT and whole body fat mass were significantly lower.
The authors calculated the TRE led to a 2% absolute reduction in CVD mortality risk and suggested that if this was maintained over time, TRE could reduce health costs and improve patient outcomes. They concluded by calling for randomised trials to further evaluate and confirm the value of this intervention.
Kirkham AA et al. Time-Restricted Eating to Reduce Cardiovascular Risk Among Older Breast Cancer Survivors J Am Coll Cardiol CardioOnc. 2022