Journal of Nutritional Science

  • Journal of Nutritional Science / Volume 1 / 2012, e14 (9 pages)
  • Copyright © The Author(s) 2012. The online version of this article is published within an Open Access environment subject to the conditions of the Creative Commons Attribution-NonCommercial-ShareAlike licence <http://creativecommons.org/licenses/by-nc-sa/2.5/>. The written permission of Cambridge University Press must be obtained for commercial re-use.
  • DOI: http://dx.doi.org/10.1017/jns.2012.15 (About DOI), Published online: 23 October 2012

Human and Clinical Nutrition

Bioavailability of vitamin C from kiwifruit in non-smoking males: determination of ‘healthy’ and ‘optimal’ intakes

Anitra C. Carra1 c1, Juliet M. Pullara1, Stephanie Morana1 and Margreet C. M. Vissersa1

a1 Centre for Free Radical Research, Department of Pathology, University of Otago, Christchurch, PO Box 4345, Christchurch, New Zealand

Abstract

Vitamin C is an essential nutrient in humans and must be obtained through the diet. The aim of this study was to determine vitamin C uptake in healthy volunteers after consuming kiwifruit (Actinidia chinensis var. Hort. 16A), and to determine the amount of fruit required to raise plasma vitamin C to ‘healthy’ (i.e. >50 µmol/l) and ‘optimal’ or saturating levels (i.e. >70 µmol/l). Leucocyte and urinary vitamin C levels were also determined. A total of fifteen male university students with below average levels of plasma vitamin C were selected for the study. Weekly fasting blood samples were obtained for a 4-week lead-in period and following supplementation with, sequentially, half, one, two and three Gold kiwifruit per d for 4–6 weeks each, followed by a final 4-week washout period. The results showed that addition of as little as half a kiwifruit per d resulted in a significant increase in plasma vitamin C. However, one kiwifruit per d was required to reach what is considered healthy levels. Increasing the dose of kiwifruit to two per d resulted in further increases in plasma vitamin C levels as well as increased urinary output of the vitamin, indicating that plasma levels were saturating at this dosage. Dividing the participants into high and low vitamin C groups based on their baseline plasma and leucocyte vitamin C levels demonstrated that it is critical to obtain a study population with low initial levels of the vitamin in order to ascertain a consistent effect of supplementation.

(Received March 29 2012)

(Revised August 08 2012)

(Accepted August 10 2012)

Key words

  • Plasma vitamin C;
  • Human saturation levels;
  • Kiwifruit supplementation;
  • Leucocytes

Correspondence:

c1 Corresponding author: Dr Anitra Carr, fax +64 3 378 6540, email anitra.carr@otago.ac.nz

Footnotes

  DTPA, diethylene triamine pentaacetic acid; RDI, recommended dietary intake.

Metrics