A Review of Nutraceuticals in Cancer Cachexia

SIMPLE SUMMARY: Cancer-related muscle wasting and inflammation, known as cachexia, leads to weight loss and worsened physical function, quality of life (QOL), and survival. The main barrier to current treatments is the lack of improvement in clinically relevant outcomes (function, QOL). Nutraceuticals are naturally occurring food products, which may be of benefit in cancer cachexia. This review describes the effect of nutraceuticals in animal models and in clinical trials in patients with cancer cachexia. Human studies mostly tested fish oil (or something similar) or amino acids (the building blocks of proteins). Body weight was the main focus, while some also assessed muscle mass and QOL, and very few measured physical function. The safety and efficacy of nutraceuticals in treating cancer-related muscle wasting remains uncertain. More animal and large human studies are needed, and they should focus on clinically meaningful outcomes, such as physical function and QOL. ABSTRACT: Cancer cachexia is largely characterized by muscle wasting and inflammation, leading to weight loss, functional impairment, poor quality of life (QOL), and reduced survival. The main barrier to therapeutic development is a lack of efficacy for improving clinically relevant outcomes, such as physical function or QOL, yet most nutraceutical studies focus on body weight. This review describes clinical and pre-clinical nutraceutical studies outside the context of complex nutritional and/or multimodal interventions, in the setting of cancer cachexia, in view of considerations for future clinical trial design. Clinical studies mostly utilized polyunsaturated fatty acids or amino acids/derivatives, and they primarily focused on body weight and, secondarily, on muscle mass and/or QOL. The few studies that measured physical function almost exclusively utilized handgrip strength with, predominantly, no time and/or group effect. Preclinical studies focused mainly on amino acids/derivatives and polyphenols, assessing body weight, muscle mass, and occasionally physical function. While this review does not provide sufficient evidence of the efficacy of nutraceuticals for cancer cachexia, more preclinical and adequately powered clinical studies are needed, and they should focus on clinically meaningful outcomes, including physical function and QOL.