Study: Time-Restricted Eating for Breast Cancer Survivors

reference

Kirkham AA, Ford KL, Topolnyski J, et al. Time-restricted eating to reduce cardiovascular risk in older breast cancer survivors: a single-arm feasibility study.JACC: CardioOncology. 2022;4(2):276-278.

Study objective

To assess the effectiveness of time-restricted nutrition in reducing cardiovascular risk in breast cancer survivors

Key to take away

Fasting for 16 hours per day during the week may reduce cardiovascular risk in breast cancer patients.

design

Single-arm feasibility study

Participant

There were 22 breast cancer survivors (mean age: 66 years ± 5 years) with an average body mass index (BMI) of 31.5 kg/m²who had undergone anthracycline chemotherapy within the last 1 to 6 years (mean: 3 years ± 1 year). Most participants (68%; n=15) either had metabolic syndrome or were eligible for pharmacological intervention to reduce cardiovascular risk. Fifty percent of participants had received left-sided irradiation and 91 percent were taking tamoxifen with or without aromatase inhibitors.

intervention

Participants fasted for 16 hours a day from Monday to Friday and only ate between 12 p.m. and 8 p.m. for two months. This time-limited meal plan is abbreviated as TRE 16:8.

Evaluated study parameters

Researchers assessed Framingham scores, metabolic syndrome, age, smoking/non-smoking status, and hypertension treatment status for cardiovascular disease risk factors.

They measured the following laboratory values ​​after an overnight fast after one of the days of the week that the participant followed the time-restricted eating protocol: glucose, total cholesterol, and high-density lipoprotein (HDL) levels.

During physical examinations, blood pressure and waist circumference were measured. The researchers analyzed visceral fat tissue using magnetic resonance imaging (MRI). They used 8-point bioimpedance to assess participants' fat and fat-free mass.

Primary outcome

Risk of cardiovascular disease, metabolic syndrome, visceral adipose tissue, fat mass and fat-free mass

Key findings

After two months of time-restricted food intake, the mean Framingham risk of cardiovascular disease decreased significantly from 10.9% to 8.6% (P=0.037). There were significantly reduced amounts of visceral adipose tissue (P=0.009), total body fat mass (P=0.046) and mean body mass (P=0.025).

There were no significantly improved outcomes in total cholesterol, HDL levels, systolic blood pressure, and mean BMI.

Of the 15 breast cancer survivors who either had metabolic syndrome or were eligible for pharmacological intervention to reduce cardiovascular risk at the start of this study, only 7 participants remained in this category after two months of time-restricted nutrition.

transparency

Study funding sources for this study are implied but not explicitly stated, and the authors have made all disclosures.

Implications and limitations for practice

This preliminary study presented some potential clinical benefits of time-restricted eating (TRE) for breast cancer survivors who are already at increased risk of cardiovascular disease. Since breast cancer survivors are at higher risk of death from cardiovascular disease, improving the accessibility of integrative interventions for treatment is very important.

Not only can time-restricted eating reduce the risk of cardiovascular disease in breast cancer survivors, but there are also a number of studies suggesting that those who practice TRE, intentionally or unintentionally, may also improve their breast cancer prognosis.^1-6In a study of more than 2,000 people with breast cancer, those who fasted more than 13 hours per night (TRE 13:11) had a significantly reduced risk of breast cancer recurrence, although there were no significant differences in mortality rates.¹This study showed that HbA levels improved significantly with each additional 2 hours of fasting per day_1cand a significantly longer sleep duration.¹However, there are conflicting data on the relationship between breast cancer prognosis and HbA_1c,^7.8It is clear that improved sleep can significantly reduce inflammatory biomarkers in breast cancer patients undergoing chemotherapy.⁹

For example, in a study of 97 people with advanced breast cancer, improved sleep significantly reduced overall mortality.¹⁰Regular eating and sleeping times are prerequisites for a healthy circadian rhythm, which has been linked to a reduced risk of cancer and cardiovascular disease.¹¹

Further studies should be conducted to distinguish whether the regular eating times or the fasting aspects of time-restricted eating are most beneficial, or whether it is the combination of both.

The study examined here looked at possible adverse symptoms such as headaches and irritability.

Systemic inflammation is associated with cancer and its recurrence. The easily measurable inflammatory marker C-reactive protein (CRP) has been linked to a poor prognosis for breast cancer.¹²Results from the 2009-2010 National Health and Nutritional Examination suggested that longer fasting intervals were associated with significantly reduced CRP levels in breast cancer patients.²For breast cancer patients with high CRP levels, TRE may be an intervention worth considering to improve their prognosis and reduce inflammation.

Studies of TRE in breast cancer patients suggest that as we collect more data, we may be able to stratify who is most likely to benefit. In a study of nearly 2,000 Chinese women, results showed that TRE may be more clinically relevant in reducing breast cancer risk for those who previously ate after 10 p.m. for a longer period of time (e.g., over 20 years), those who regularly ate between 12 and 2 a.m., those who ate foods other than fruits and vegetables late at night, and those with a BMI under 25.⁴

Although TRE is a low-risk and cost-effective option, there are potential side effects to consider. The study examined here looked at possible adverse symptoms such as headaches and irritability. Other studies have also found similar symptoms.¹³Less common side effects of TRE include vomiting, diarrhea, nausea, constipation, dizziness, increased thirst, and fatigue.¹³Studies have shown that these side effects generally lessen over time.¹³

As with any integrative nutrition protocol, it is paramount to assess each patient individually and educate them about the risks and benefits of a particular TRE protocol so that they can make an informed decision about whether to continue with time-restricted nutrition.