Vitamin C and A1c Relationship in the National Health and Nutrition Examination Survey (NHANES) 2003–2006

Abstract

Objective: The scope of the diabetes epidemic stresses the critical need for primary prevention. The consumption of foods high in vitamin C has been associated with lower risk of diabetes. The aim of this study was to analyze the relation between vitamin C concentration and glycemic control index in a large sample of U.S. adults without a history of diabetes.

Methods: We analyzed data collected from 7697 adult participants in the National Health and Nutrition Examination Survey (NHANES) 2003–2006 who did not report a history of diabetes. Multivariate linear regression analyzed the association of vitamin C and hemoglobin A1c (A1c) levels after accounting for potential confounders. We also conducted stratified analyses based on race/ethnicity, gender, age group, body mass index, and vitamin D status.

Results: Vitamin C concentrations were inversely associated with A1c (p = 0.0202). Stronger inverse associations were observed in subjects 18–44 years of age (p = 0.0017), as well as in female (p = 0.0035) and Mexican American (p = 0.0149) subgroups. Evidence of a significant interaction between vitamin C and vitamin D was noted in subjects aged 18–44 years and in females (p = 0.0073 and 0.0095 respectively), with the inverse association tending to be evident at lower levels of vitamin D.

Conclusions: Vitamin C status may influence glycemic control. Investigators should be cognizant of the interaction of vitamins C and D and should take this into consideration in planning future studies.

Key words::

• vitamin C
• vitamin D
• A1c

ACKNOWLEDGEMENT

The authors would like to thank Dr. George Kuchel at the UConn Center on Aging for helpful comments on the manuscript.

Table 1. Vitamin C and A1c among Adults without a Self-Reported History of Diabetes Mellitus*: National Health and Nutrition Examination Survey, 2003–2006 (n = 7697)

Table 2. Parameter Estimates (p Values) for the Association of A1c Levels with Vitamin C Status Overall, by Age, Gender, and Race/Ethnicity in Persons without a Self-Reported History of Diabetes Mellitus: National Health and Nutrition Examination Survey, 2003–2006

Table 3. Parameter Estimates (95% Confidence Interval) for the Association of Vitamin C Status with A1c Levels by Quartile of Vitamin D in Persons without a Self-Reported History of Diabetes Mellitus Overall and Subgroup Analyses: National Health and Nutrition Examination Survey, 2003–2006 (N = 7697)

Notes

V.L.F. was supported by in part by National Institutes of Health (NIH) Grant 5R01CA129140.