A randomized steady-state bioavailability study of synthetic versus natural (kiwifruit-derived) vitamin C

Nutrients. 2013 Sep 17;5(9):3684-95. doi: 10.3390/nu5093684.

Abstract

Whether vitamin C from wholefoods has equivalent bioavailability to a purified supplement remains unclear. We have previously showed that kiwifruit provided significantly higher serum and tissue ascorbate levels than synthetic vitamin C in a genetically vitamin C-deficient mouse model, suggesting a synergistic activity of the whole fruit. To determine if these results are translatable to humans, we carried out a randomized human study comparing the bioavailability of vitamin C from kiwifruit with that of a vitamin C tablet of equivalent dosage. Thirty-six young non-smoking adult males were randomized to receive either half a gold kiwifruit (Actinidia Chinensis var. Hort 16A) per day or a comparable vitamin C dose (50 mg) in a chewable tablet for six weeks. Ascorbate was monitored weekly in fasting venous blood and in urine, semen, leukocytes, and skeletal muscle (vastus lateralis) pre- and post-intervention. Dietary intake of vitamin C was monitored using seven day food and beverage records. Participant ascorbate levels increased in plasma (P < 0.001), urine (P < 0.05), mononuclear cells (P < 0.01), neutrophils (P < 0.01) and muscle tissue (P < 0.001) post intervention. There were no significant differences in vitamin C bioavailability between the two intervention groups in any of the fluid, cell or tissue samples tested. Overall, our study showed comparable bioavailability of synthetic and kiwifruit-derived vitamin C.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actinidia / chemistry*
  • Adolescent
  • Adult
  • Animals
  • Antioxidants / administration & dosage
  • Ascorbic Acid / administration & dosage*
  • Ascorbic Acid / blood
  • Ascorbic Acid / pharmacokinetics*
  • Ascorbic Acid / urine
  • Biological Availability
  • Cross-Over Studies
  • Dietary Supplements*
  • Fruit / chemistry*
  • Humans
  • Leukocytes / metabolism
  • Male
  • Muscle, Skeletal / metabolism
  • Semen / metabolism
  • Young Adult

Substances

  • Antioxidants
  • Ascorbic Acid