The Impact of Modern Dietary Practices on Cancer Risk and Progression: A Systematic Review

Cancer is a leading cause of mortality around the world, despite continued advancements in the management of cancer. Recent research efforts have shifted to evaluating the role that modifiable risk factors play in cancer risk and development, as diet and nutrition have been found to play a significant role in the onset and progression of cancer. As a result, there has been an increasing focus on the impact of dietary modifications on preventing the onset, progression, and reoccurrence of cancer. In this systematic review, data were collected on three common diets, the Mediterranean diet (MD), ketogenic diet (KD), and plant-based diet, to gain insight into the application of these three dietary modification approaches for risk prevention and limitation of cancer burden. Initially, 4,397 articles were identified from three databases (Ovid, Web of Science, and CINHAL). After removing studies based on the exclusion criteria, only 23 studies were eligible to be included in the systematic review of which 15 evaluated the MD, four assessed the ketogenic diet, and four evaluated the plant-based diet. Each article was considered for its methods, procedures, and findings. The findings indicate that dietary interventions may effectively reduce the odds of cancer development and the advancement of diagnosed cancers. With the introduction of the MD, KD, and plant-based diets, significant improvements in lowering cancer development, recurrence-free status, and limiting tumor growth were noted across numerous cancer types. Currently, the MD has been extensively studied in the literature, and amongst the widest variety of cancer types. Additional information and evaluation are required on the ketogenic and plant-based diets to fully understand their impact on the cancer burden across a wider subset of cancers. Clinicians should evaluate and recommend nutritional adaptations to their patients to limit the development of specific cancers and as an adjunctive therapy to traditional pharmacological treatment options for patients with diagnosed cancers.