Caloric restriction and fasting-mimicking diets in the treatment of cancer patients.

Abstract

Different forms of caloric restriction for patients with cancer are widely advertised in lay circles, based mainly on promising preclinical experiments, while evidence from clinical trials is still preliminary. This review aims to present physiological responses to fasting and update knowledge on recently accumulated evidence from preclinical models and clinical trials. Like other mild stressors, caloric restriction induces hormetic changes in healthy cells, which increase the tolerance to subsequent more severe stressors. While protecting healthy tissues, caloric restriction sensitizes malignant cells to toxic interventions because of their deficiencies in hormetic mechanisms, especially control of autophagy. In addition, caloric restriction may activate anticancer-directed immune cells and deactivate suppressive cells, thus increasing immunosurveillance and anticancer cytotoxicity. These effects may combine to increase the effectivity of cancer treatments while limiting adverse events. Though evidence obtained from preclinical models is promising, clinical trials in cancer patients so far have been preliminary. In clinical trials it will remain essential to avoid inducing or aggravating malnutrition. Based on physiology and evidence from preclinical models, caloric restriction is a promising candidate as a potential combination partner for clinical anticancer treatment. However, large randomized clinical trials investigating effects on clinical outcome in patients with cancer are still lacking.