Cancer cachexia (CC) is a complex syndrome of bodily wasting and progressive functional decline. Unlike
starvation,
cachexia cannot be reversed by increased energy intake alone. Nonetheless, targeted
nutritional support is a necessary component in multimodal syndrome management. Due to the highly catabolic nature of
cancer cachexia,
amino acid supplementation has been proposed. Interestingly,
leucine has been found to increase
protein synthesis and decrease protein degradation via
mTORC1 pathway activation. Multiple pre-clinical studies have explored the impact of
leucine supplementation in cachectic
tumor-bearing hosts. Here, we provide an overview of
leucine's proposed modes of action to preserve lean mass in
cachexia and review the current pre-clinical literature related to
leucine supplementation during CC. Current research indicates that a
leucine-rich diet may attenuate CC symptomology; however, these works are difficult to compare due to methodological differences. There is need for further pre-clinical work exploring
leucine's potential ability to modulate
protein turnover and immune response during CC, as well as the impact of additive
leucine on
tumor growth.