Scurvy: A presenting sign of psychosis

Scurvy: old disease, new lessons

Scurvy, the condition associated with severe vitamin C deficiency, is believed to be one of the oldest diseases in human history. It was particularly prevalent during the Age of Sail, when long sea voyages without access to fresh food resulted in an epidemic which claimed millions of lives; however, scurvy has existed across time and geography, occurring whenever and wherever diets are devoid of vitamin C. Young children, specifically, were affected by the emergence of 'infantile scurvy' in the 19th century owing to the use of heated milk and manufactured infant foods of poor nutritional quality. Scurvy continues to occur in at-risk groups. In children and youths, it is primarily observed in the context of autism spectrum disorder and feeding problems such as a limited food repertoire and high-frequency single food intake. Diagnosis may be delayed and invasive testing undertaken owing to clinicians' lack of familiarity with the disease, or the mistaken assumption that it is exclusively a disease of the past. The aetiology, clinical manifestations and treatment of scurvy are described. Its long history and current epidemiology are also reviewed, demonstrating that scurvy is very much a disease of the present. It is suggested that future efforts should focus on (i) anticipatory guidance and early nutritional intervention, informed by an understanding of scurvy's epidemiology, with the aim of preventing the disease in those at risk, and (ii) prompt recognition and treatment to minimise morbidity and healthcare costs.Abbreviations: ASD: autism spectrum disorder.

Neurobiology of vitamin C: Expanding the focus from antioxidant to endogenous neuromodulator

Ascorbic acid (AA) is a water-soluble vitamin (C) found in all bodily organs. Most mammals synthesize it, humans are required to eat it, but all mammals need it for healthy functioning. AA reaches its highest concentration in the brain where both neurons and glia rely on tightly regulated uptake from blood via the glucose transport system and sodium-coupled active transport to accumulate and maintain AA at millimolar levels. As a prototype antioxidant, AA is not only neuroprotective, but also functions as a cofactor in redox-coupled reactions essential for the synthesis of neurotransmitters (e.g., dopamine and norepinephrine) and paracrine lipid mediators (e.g., epoxiecoisatrienoic acids) as well as the epigenetic regulation of DNA. Although redox capacity led to the promotion of AA in high doses as potential treatment for various neuropathological and psychiatric conditions, ample evidence has not supported this therapeutic strategy. Here, we focus on some long-neglected aspects of AA neurobiology, including its modulatory role in synaptic transmission as demonstrated by the long-established link between release of endogenous AA in brain extracellular fluid and the clearance of glutamate, an excitatory amino acid. Evidence that this link can be disrupted in animal models of Huntington´s disease is revealing opportunities for new research pathways and therapeutic applications (e.g., epilepsy and pain management). In fact, we suggest that improved understanding of the regulation of endogenous AA and its interaction with key brain neurotransmitter systems, rather than administration of AA in excess, should be the target of future brain-based therapies.