Serum vitamin C and the prevalence of vitamin C deficiency in the United States: 2003-2004 National Health and Nutrition Examination Survey (NHANES)

Am J Clin Nutr. 2009 Nov;90(5):1252-63. doi: 10.3945/ajcn.2008.27016. Epub 2009 Aug 12.


Background: Vitamin C (ascorbic acid) may be the most important water-soluble antioxidant in human plasma. In the third National Health and Nutrition Examination Survey (NHANES III, 1988-1994), approximately 13% of the US population was vitamin C deficient (serum concentrations <11.4 micromol/L).

Objective: The aim was to determine the most current distribution of serum vitamin C concentrations in the United States and the prevalence of deficiency in selected subgroups.

Design: Serum concentrations of total vitamin C were measured in 7277 noninstitutionalized civilians aged > or =6 y during the cross-sectional, nationally representative NHANES 2003-2004. The prevalence of deficiency was compared with results from NHANES III.

Results: The overall age-adjusted mean from the square-root transformed (SM) concentration was 51.4 micromol/L (95% CI: 48.4, 54.6). The highest concentrations were found in children and older persons. Within each race-ethnic group, women had higher concentrations than did men (P < 0.05). Mean concentrations of adult smokers were one-third lower than those of nonsmokers (SM: 35.2 compared with 50.7 micromol/L and 38.6 compared with 58.0 micromol/L in men and women, respectively). The overall prevalence (+/-SE) of age-adjusted vitamin C deficiency was 7.1 +/- 0.9%. Mean vitamin C concentrations increased (P < 0.05) and the prevalence of vitamin C deficiency decreased (P < 0.01) with increasing socioeconomic status. Recent vitamin C supplement use or adequate dietary intake decreased the risk of vitamin C deficiency (P < 0.05).

Conclusions: In NHANES 2003-2004, vitamin C status improved, and the prevalence of vitamin C deficiency was significantly lower than that during NHANES III, but smokers and low-income persons were among those at increased risk of deficiency.

MeSH terms

  • Adolescent
  • Adult
  • Ascorbic Acid / blood*
  • Ascorbic Acid Deficiency / epidemiology*
  • Body Mass Index
  • Child
  • Cross-Sectional Studies
  • Diet
  • Dietary Supplements
  • Ethnic Groups / statistics & numerical data
  • Female
  • Humans
  • Interviews as Topic
  • Male
  • Nutrition Surveys*
  • Poverty / statistics & numerical data
  • Probability
  • Smoking / adverse effects
  • Socioeconomic Factors
  • United States / epidemiology
  • Young Adult


  • Ascorbic Acid