Professor Stephen Chambers is an Infectious Diseases physician with Canterbury District Health Board and member of the Department of Pathology, University of Otago, Christchurch. He studied at the University of Otago, London School of Hygience and Tropical Medicine, and worked in Northwick Park Hosptial in London, and Ohio State University and University of Wisconsin in the USA. Research interests include pharmacokinetics and dynamics of antibiotics, the pathogensis of sepsis, nutrition and infection, staphylococcal disease, leprosy and intermediary metabolism.
Can Vitamin Supplementation Improve Outcomes From Infection?
The advent of antimicrobial agents has revolutionized treatment of bacterial infections by reducing both morbidity and mortality. Despite this we have difficulty in improving further the outcomes once sepsis has become established. One potential avenue is to look at approaches to improve supportive care.
Vitamin C is a water soluble vitamin acquired form the diet but with low storage in human bodies. Unlike most other mammals, which increase synthesis of plasma and tissue levels in response to insult, humans and other primates cannot synthesise vitamin C and levels drop dramatically with stress and infection. Multiple lines of evidence from in vitro and animal studies demonstrate that vitamin C administration modulates the neutrophilic response, reduces oxidative stress, improves coagulopathy and platelet function, synthesis of noradrenaline and vasopressin (as is a required co-factor for synthesis) and reduces mortality. Results from clinical trials of supplementation in the intensive care setting are promising but the optimal dose, and duration have not yet been determined. The largest and most recent trial found no acute effect but indicated that 28 day mortality was reduced in patients in the ICU with sepsis and acute respiratory failure.
Vitamin D is a fat soluble vitamin that is stored in the human liver and other tissues. Vitamin D is important for activating the innate immune system and modulates the adaptive immune system. Clinical trials indicate that vitamin D supplementation was safe, and it protected against acute respiratory infections overall. Very deficient individuals (<25 nmol/l ) and those not receiving bolus doses experienced the benefit. The effect of vitamin D supplementation in tuberculosis is unclear. Genetic polymorphisms may contribute to the variation in response to supplements.
Vitamin A plays a role in many areas of the immune system, particularly in T cell differentiation and proliferation. Vitamin A deficiency is linked to the development of mycobacterial disease but intervention trials are needed to establish causation.