Does when we eat make a difference to our health? We know that food choices can impact cancer risk but what if the timing plays a role as well? Over several decades, overconsumption of food has contributed to an increase in a number of diseases, including cancer. What if this could be reversed, or slowed down, by fasting? Would that improve how people with cancer respond to chemotherapy? Could simply changing eating patterns to reduce overall intake be a way to prevent and/or manage cancer? All of these are important questions, and investigators are undertaking new initiatives to study how nutrition and dietary behaviours affect people with cancer.
Background
Thirty to fifty percent of all cancer cases are estimated to be preventable through healthy lifestyles and avoiding environmental carcinogens and infections (“A Summary of the Third Expert Report,” 2018). This evidence suggests that diet plays a significant role in cancer prevention and has led to the development of population-level, evidence-based diet recommendations to minimize cancer risk factors. However, individuals can experience different responses to the same diet. This variability “may result from a range of determinants including age, sex, habitual dietary habits, genetics, epigenetics, and gut microbiota. This will affect the absorption, distribution, metabolism, and excretion of compounds and metabolites, and thus affect bioavailability and biological responsiveness” (De Roos & Brennan, 2017), which may hold implications in cancer.
As described by Locasale & Cantley (2011) and Hirschey et al. (2015), in the process of oncogenesis cells undergo a complex metabolic rearrangement resulting in dysregulation of cellular metabolism – a hallmark of cancer. This metabolic dysregulation can be exploited as a target for cancer treatment (Hirschey et al., 2015). Understanding the intersection of metabolism, dietary profiles, and the gut microbiome holds potential to uncover acceptable and feasible nutrition interventions that are clinically beneficial, safe and less toxic to be used in adjunct to our current, standard of care.
A review of clinical trials on intermittent fasting in cancer can be found here: https://pubmed.ncbi.nlm.nih.gov/35639262/
Study 1 - Feasibility Study of Intermittent Fasting in Chronic Lymphocytic Leukemia and Small Lymphocytic Lymphoma (CLL/SLL) Patients at BC Cancer- Victoria
ClinicalTrials.gov Identifier: NCT04626843
Summary: Under the watchful eye of Medical Oncologist and Principal Investigator, Dr. Nicol MacPherson, and with autophagy studies and metabolomics led by cancer immunologist, Dr. Julian Lum, the investigators are examining the effects of intermittent fasting (IF) (aka. time restricted feeding) in patients with chronic lymphocytic leukemia (CLL) and small lymphocytic lymphoma (SLL). CLL and SLL are considered to be one disease with different manifestations. It is the most common leukemia in adults in Western countries, most often diagnosed in older adults, and is presently incurable. The advantage of choosing this patient population is that the cancer is easily assessed with a blood test measuring the amount of cancerous white cells (lymphocytes). With the support of an oncology dietitian, participants are limiting their eating to an 8-hour window for six days per week, for a duration of either 3 or 6 months. Participants do not need to limit their total caloric intake or follow specific food recommendations.
Through a series of blood tests, stool samples, and qualitative surveys, this study is investigating the biochemical effects of IF on CLL tumor control and autophagy induction by using a case-controlled study of CLL/SLL patients at BC Cancer- Victoria. The study is also investigating the duration of the biochemical effects after completing the IF.
Sponsorship: This research is generously funded by the Grewal family and the BC Cancer Foundation.
Status: This study is nearing completion in October 2022. Please send any questions to Eleah Stringer, Research Lead at eleah.stringer@bccancer.bc.ca
Study 2 - Does timing matter? A case crossover study of intermittent fasting in patients with CLL/SLL at BC Cancer- Victoria
Summary: Does when we eat make a difference to our health? We know that food choices can impact cancer risk but what if timing plays a role as well? Evidence shows that fasting may slow cancer growth on a cellular level through a process called autophagy. This team is currently completing a study testing the effects of intermittent fasting (IF) (splitting the day into 16 hr fasting and 8 hr feeding windows, for 3-6 months) in patients with chronic lymphocytic leukemia (CLL) and small lymphocytic lymphoma (SLL). While early results look promising, we don’t know how other fasting methods compare, nor do we know which fasting method is preferred by patients. We plan to compare two common IF routines to see if they exert differential effects on tumour proliferation (lymphocyte count), markers of autophagy, inflammation, and gut bacteria-derived metabolites. We also want to learn which strategy patients prefer.
Sponsorship: This research is generously funded by the BC Cancer Foundation.
Status: This study is anticipated to begin in the fall 2022. Any questions can be sent to Eleah Stringer, Research Lead at eleah.stringer@bccancer.bc.ca
Study 3 - Does timing matter? A trial of intermittent fasting in haematological malignancies
Summary: While new and emerging evidence continues to support a myriad of health benefits with intermittent fasting (IF), randomized control trials in cancer patients remain scant (Giannakou et al., 2020). Additionally, there is a paucity of literature on adherence and acceptability of IF. Understanding the patient experience with these dietary interventions is paramount as “non-adherence to lifestyle changes raises an important issue since adherence level to dietary advice is a key determinant of the effectiveness of dietary treatment” (Desroches et al., 2011). Furthermore, the study team is unaware of any precision nutrition research that directly investigates the clinical and cellular response of IF while considering the patients’ safety, experience, and quality of life. Though our feasibility work appears promising, results will not be quantified to statistical significance, limiting the confidence in findings. This research will statistically clarify the impact of IF on clinical outcomes (e.g. lymphocyte count), correlative biomarkers of autophagy, quality of life, and the gut microbiome while describing the patient experience. Sex and gender will be integrated in this research to enhance gender-equity.
Sponsorship: This research is generously funded by the BC Cancer Foundation, the Lum Lab, Michael Smith Health Research BC Health Professional-Investigator Award, and the Lotte & John Hecht Memorial Foundation
Status: This study is anticipated to begin in 2024. If you have been diagnosed with CLL/SLL, are not receiving anti-cancer treatment, and live in British Columbia and would like to receive an update when the study is open for recruitment, please email Eleah Stringer at eleah.stringer@bccancer.bc.ca