Vitamin C deficiency in cancer patients

Purpose: To assess the prevalence of vitamin C deficiency within a group of hospice patients. To assess the relationship between plasma vitamin C, dietary intake and subsequent survival. Methods: Patients with advanced cancer were recruited from a large hospice. Data were collected on demographic details, physical functioning and smoking history. An estimate was obtained of the number of weekly dietary portions consumed equivalent to 40 mg of vitamin C, the recommended daily intake. Plasma vitamin C was measured by a single blood sample. The study had local ethical approval. Results: Fifty patients were recruited (mean age 65.2 years, 28 female). Plasma vitamin C deficiency was found in 15 (30%). Dietary intake of vitamin C was correlated to plasma vitamin C (r = 0.518, P <0.0001). Low dietary intake, low albumin, high platelet count, high CRP level and shorter survival were all significantly associated with low plasma vitamin C concentrations (< 11 mumol/L). There was no correlation between plasma vitamin C, smoking history or physical functioning. Conclusion: Vitamin C deficiency is common in patients with advanced cancer and the most important factors determining plasma levels are dietary intake and markers of the inflammatory response. Patients with low plasma concentrations of vitamin C have a shorter survival.