BIOMARKERS FOR VITAMIN C REQUIREMENT

• Published in: Annals of nutrition and metabolism 2017-10, Vol.71 (Suppl. 2), p.148
• Main Authors: Elste, Volker, Troesch, Barbara, Eggersdorfer, Manfred, Weber, Peter
• Format: Article
• Language: English
• Subjects: Adults; Arteriosclerosis; Ascorbic acid; Atherosclerosis; Biomarkers; Cardiovascular disease; Cardiovascular diseases; Chemokinesis; Chemotaxis; Children; Colds; Common cold; Diet; Dietary intake; Immune response; Neutrophils; Observational studies; Optimization; Reduction; Vascular diseases; Vitamin C
• ISSN: 0250-6807; 1421-9697
• DOI: 10.1159/000480486

Intake recommendations for vitamin C are currently defined using markers for status, as no suitable functional biomarker has as yet been identified. There are different functional biomarkers for Vitamin C but up to now, no one was identified that could be used as a basis to define dietary intake recommendations for vitamin C. Emerging evidence support neutrophil motility as such a functional biomarker. A recent in vitro study showed that adequate levels of vitamin C were needed for this function to work optimally when measured as chemotaxis and chemokinesis. Furthermore, in a human intervention study with healthy subjects, neutrophil motility was optimal at intakes at ~250 mg/d. These findings are supported by established knowledge including a Cochrane review which showed a significant reduction in the duration of episodes of common cold in children as well as in adults with regular vitamin C intakes in a similar range. This is in line with human kinetic studies where plasma saturation was reached with 200 mg/ day and also the related vitamin C transporters reached their maximum at this dose. Additionally, in observational studies it was shown that at plasma level of 75 µmol/L, which can be reached with vitamin C intakes of ≥200 mg/d, incidences of cardiovascular disease were lowest. A relationship between vitamin C concentration, severity of atherosclerosis and inflammation in peripheral artery disease patients could be shown. However, additional studies are needed to investigate further the reliability and accuracy of neutrophil motility as a functional marker of vitamin C dependent immune function. Given the number of people affected by common cold, cardiovascular disease and others, defining recommendations with the highest risk reduction for these diseases is of paramount importance. The evidence would suggest that daily intakes of 200 mg vitamin C might be advisable for the general adult population, which can be achieved by means of a diverse diet.