In a Canadian single-institution feasibility study reported in JACC: CardioOncology, Amy A. Kirkham, PhD, of the University of Toronto, and colleagues found that a time-restricted eating intervention reduced cardiovascular risk among older breast cancer survivors with risk factors for cardiovascular disease mortality.1
In the study, breast cancer survivors from a single center aged ≥ 60 years with overweight or obesity (body mass index [BMI] ≥ 25 kg/m2) who had completed anthracycline treatment within the past 1 to 6 years were invited by mail to participate in a time-restricted eating intervention. Recruitment occurred from August 2020 to January 2021, during the COVID-19 pandemic and prior to vaccine availability.
“We found that weekday 16:8 [time-restricted eating] was a highly feasible and low-symptom intervention that reduces calorie intake without fat-free mass loss or the need to count calories among [breast cancer survivors].”— Amy A. Kirkham, PhD
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Time-restricted eating interventions commonly consist of limiting energy intake within a specified time window, usually 8 hours, followed by fasting for 16 hours (16:8 time-restricted eating). In the current study, breast cancer survivors were asked to eat ad libitum (as much or as often as desired) between 12 noon and 8 PM on weekdays and any time of day on weekends and to consume only water, black coffee, or black tea outside of those hours for 8 weeks. Intervention support consisted of the following:
Phone calls involved discussion of adherence, symptoms, barriers, and facilitators.
Of 228 invited patients, 22 (10%) enrolled and completed the intervention. Among the 22 patients, the mean age was 66 years, mean BMI was 31 kg/m2, and the mean time from completion of anthracycline treatment was 3 years. No patients had received trastuzumab, 50% had received left-sided radiation therapy, and 91% were currently receiving tamoxifen and/or aromatase inhibitor treatment.
Patients responded to 99% of text messages and adhered to ≥ 16 hours of fasting for a median of 98% (range = 85%–100%) of days. Reported adverse events, including headache and irritability, were minor and persisted for 5 minutes to 3 hours.
Compared with baseline, after 8 weeks, there was no significant change in fat-free mass (−0.1 ± 1.6 kg, P = 0.76). Calorie intake was reduced by a median of 450 kcal (interquartile range [IQR] = 28–765 kcal), representing a 22% relative reduction (P < .001). Median Framingham 10-year cardiovascular disease risk decreased from 10.9% (IQR = 8.6%–13.7%) to 8.6% (IQR = 7.6%–10.0%), representing a 15% relative reduction (P = .037).
Significant reductions in mean magnetic resonance imaging–derived visceral adipose tissue (−5% ± 7%, P = .009), median bioelectric impedance-derived whole-body fat mass (−0.9 kg, IQR = −1.5 to 0.1 kg, P = .046), and median body mass (−1.0 kg, IQR = −2.3 to 0.2 kg, P = .025) were observed, with no significant change in mean BMI (−0.2 ± 0.7 kg/m2, P = .10).
At baseline, 15 patients were classified as cardiometabolically unhealthy, defined as meeting criteria for metabolic syndrome or for pharmacologic preventive treatment of cardiovascular disease risk (statins), according to Canadian Cardiovascular Society guidelines. After 8 weeks, 8 of the 15 patients (53%) no longer met criteria for metabolic syndrome or pharmacologic treatment, having been reclassified as being at “low” (< 10%) 10-year Framingham cardiovascular disease risk.
The investigators concluded: “We found that weekday 16:8 [time-restricted eating] was a highly feasible and low-symptom intervention that reduces calorie intake without fat-free mass loss or the need to count calories among [breast cancer survivors]. Our preliminary efficacy findings include a 2% absolute or 15% relative [cardiovascular disease] risk reduction within just 8 weeks among [breast cancer survivors] at risk for [cardiovascular disease] mortality because of overweight or obese status, older age, and receipt of anthracyclines. [Time-restricted eating] also significantly decreased [visceral adipose tissue], which our team has previously found to accumulate rapidly with cardiotoxic treatment and predict later cardiac events among [breast cancer survivors].”
DISCLOSURE: Dr. Kirkham reported no conflicts of interest.
1. Kirkham AA, Ford KL, Topolnyski J, et al: Time-restricted eating to reduce cardiovascular risk among older breast cancer survivors: A single-arm feasibility study. JACC: CardioOncol 4:276-278, 2022.