Plant-Based and Ketogenic Diets As Diverging Paths to Address Cancer

Abstract

ImportanceAs the incidence of cancer and metabolic disorders, such as obesity, concurrently rise, there has been increasing awareness of the pervasive effect of nutrition. The whole foods plant-based diet (WFPBD) and ketogenic diet (KD) have gained popularity in oncology, and this topic is increasingly permeating clinical dialogue.ObservationsDietary intake is associated with multiple pathways involved in carcinogenesis and tumor progression. Consumption of a plant-enriched diet is associated with reduced cancer incidence and is recommended by dietary guidelines for cancer prevention. Despite a starkly different nutrient composition, a WFPBD and KD can be associated with weight loss, decreased inflammation, and decreased insulin levels. In addition, a WFPBD is associated with increased fiber, phytochemicals, and butyrate levels and decreased insulin-like growth factor 1 levels, whereas a KD exerts potential anticancer effects by increasing β hydroxybutyrate levels. A KD may be of interest in select, less common settings, such as tumors treated with phosphatidylinositol 3-kinase inhibitors, which induce hyperinsulinemia and hyperglycemia. Completed interventional trials have focused on increasing fruit and vegetable intake or reducing fat intake but have not specifically tested WFPBD or KD for cancer prevention or treatment. Currently available data support plant-based diets as opposed to KD as part of a lifestyle associated with reduced cancer risk. In the postdiagnosis setting, there are currently no rigorously tested approaches that support the recommendation of any diet to treat cancer.Conclusions and RelevanceThe results of this review suggest that the collective evidence supports plant-enriched diets vs KD for the reduction of cancer risk and the improvement of metabolic disorders in survivors. Additional prospective randomized clinical trials are needed to encourage use of dietary modification across the cancer continuum. Rigorous trial designs that adapt classical oncologic end points may identify populations that are likely to benefit from starkly contrasting diets. Current data support prioritization of plant-based diets, and future data could further personalize dietary recommendations in cancer populations.

Translating energy balance research from the bench to the clinic to the community: Parallel animal‐human studies in cancer

“…This study combines exercise and groundwork laid in support of a plant-based diet for favorably modifying the biologic effects of obesity that promote tumor growth. 109,110 Future directions for the incorporation of exercise into standardof-care therapy for cancer should include preclinical studies with parallel clinical testing to determine when and how to optimally harness a potential anticancer effect of exercise. Certainly, exercise prescription is recommended throughout the cancer continuum when used for symptom control and/or management of treatment-related adverse effects.…”

“…For example, a current phase 2 study in postmenopausal women on adjuvant aromatase‐inhibitor therapy for breast cancer is testing the combination of aerobic exercise with a plant‐based diet deployed by digitally supervised, home‐based exercise and preprepared meal delivery (ClinicalTrials.gov identifier NCT04298086). This study combines exercise and groundwork laid in support of a plant‐based diet for favorably modifying the biologic effects of obesity that promote tumor growth 109,110 …”

Pre-Diagnosis Dietary Patterns and Risk of Multiple Myeloma in the NIH-AARP Diet and Health Study

“…Plant-based diets are rich in fiber and phytochemicals and are associated with reduced cancer risk and improved survival in cancer through multiple mechanisms such as improved BMI, decreased inflammation, decreased insulin levels, decreased insulin-like growth factor 1 and improved stool microbiome [13]. As the role of gut dysbiosis is being increasingly recognized in the pathogenesis of MM, diet, the largest driver of microbiome composition can no longer be ignored [14].…”

Plant-based diets to reduce prostate cancer risk and improve prostate cancer outcomes—ready for prime time?

“…Historically, constituents in fruit and vegetables were studied to elucidate mechanisms linking their intake with reduced PC risk. While results from observational studies are encouraging, Level 1 evidence to support the benefits of specific constituents, plant-based dietary patterns, and plant-based foods is lacking [2].…”

“…While only 1% of HPFS men and <2% of UK Biobank participants were classified as strict vegetarian or vegan, interest in plantbased diets is increasing [2]. That being said, other dietary approaches beyond plant-based have also suggested PC benefits including low-carbohydrate [14,15], ketogenic diet [16], lowglycemic diet [17], and low-fat fish oil diet [18].…”