ABSTRACT
As a group, vitamins are chemically diverse and are not linked by any common threads in chemical structure. With this variety in both form and biological function the impact of advanced cancer on status will inevitably be greater for some vitamins than others. We are entirely dependent on dietary and other exogenous sources of vitamins to satisfy our requirements. Common effects of cancer progression include anorexia, nausea, vomiting and bowel obstruction, all of which restrict dietary intake. Vitamin availability is also challenged by the side effects of treatment interventions for cancers, both surgical and non-surgical (chemotherapy, radiotherapy and molecular-targeted treatments) which may cause mucositis, alimentary tract disturbances or diarrhoea, leading to malabsorption. Moreover, the utilisation of vitamins may increase in response to chemotherapy and radiotherapy. Status can be further challenged through the sequestering of vitamins by tumour cells to fuel rapid growth and proliferation.
Prolonged suboptimal exposure to several vitamins has been implicated in the development of cancers, and there are indications that the monitoring of vitamin status may act as a marker of disease progression. However, to date the study of these micronutrients in patients with terminal cancer has received surprisingly little attention.
Increasing numbers of static and functional laboratory markers of vitamin status are available. These should be utilised to assess the prevalence of fat- and water-soluble vitamin deficiencies in patients with advanced cancer to aid the provision of evidence-based nutritional support.
