Abstract
Background: Recent studies have highlighted that body weight is an important determinant of vitamin C requirements, although this is not taken into account in the present nutrient recommendations for adults. Considering the rising prevalence of obesity globally, this suggests that increasing proportions of the population are not achieving the expected nutritional status based on the intake of the current RDA supposed to provide 97.5% of the population with a sufficient nutrient status. Research Objective: To investigate how increased body weight may impact nutritional sufficiency of vitamin C, based on the relationship between dietary intake and plasma concentration. Methods: Using two of the largest and most well-documented cohorts-the EPIC-Norfolk cohort covering the UK and the NHANES cohort covering the USA-we estimated the effect of body weight on the vitamin C dose vs concentration relationship to derive weight-based requirements to achieve an 'adequate' plasma concentration of vitamin C estimated to 50 µmol/L. Results: Significant inverse correlations between body weight and plasma concentrations of vitamin C were observed in both cohorts (p<0.0001). Moreover, we found that only about two thirds of the cohorts achieved an adequate plasma vitamin C status by consuming the national RDA or above, while only between one third and half of the cohorts achieved adequacy by an intake of the local RDA ± 10%. Discussion: Problems in reaching adequate vitamin C status is significantly related to increased body weight, where heavier individuals need substantially higher intakes to achieve plasma concentrations similar to that of a male reference individual of 70 kg. The present data demonstrates that a considerable and expectedly increasing proportion of the world population are unable to achieve an adequate target plasma concentration with the current recommended daily intake of vitamin C. This needs to be considered in future public health recommendations, when revising nutrient recommendations.