Supplementation of a western diet with golden kiwifruits (Actinidia chinensis var.'Hort 16A':) effects on biomarkers of oxidation damage and antioxidant protection.

Asgeir Brevik,Anita Piasek,Isabel Gaivão,Andrew R Collins,Rune Blomhoff,Anette Karlsen,Aud Jørgenesen,Tirill Medin,Turid Veggan,Asim K Duttaroy,Johanna Elilasson

doi:10.1186/1475-2891-10-54

Abstract

BackgroundThe health positive effects of diets high in fruits and vegetables are generally not replicated in supplementation trials with isolated antioxidants and vitamins, and as a consequence the emphasis of chronic disease prevention has shifted to whole foods and whole food products.MethodsWe carried out a human intervention trial with the golden kiwifruit, Actinidia chinensis, measuring markers of antioxidant status, DNA stability, plasma lipids, and platelet aggregation. Our hypothesis was that supplementation of a normal diet with kiwifruits would have an effect on biomarkers of oxidative status. Healthy volunteers supplemented a normal diet with either one or two golden kiwifruits per day in a cross-over study lasting 2 × 4 weeks. Plasma levels of vitamin C, and carotenoids, and the ferric reducing activity of plasma (FRAP) were measured. Malondialdehyde was assessed as a biomarker of lipid oxidation. Effects on DNA damage in circulating lymphocytes were estimated using the comet assay with enzyme modification to measure specific lesions; another modification allowed estimation of DNA repair.ResultsPlasma vitamin C increased after supplementation as did resistance towards H2O2-induced DNA damage. Purine oxidation in lymphocyte DNA decreased significantly after one kiwifruit per day, pyrimidine oxidation decreased after two fruits per day. Neither DNA base excision nor nucleotide excision repair was influenced by kiwifruit consumption. Malondialdehyde was not affected, but plasma triglycerides decreased. Whole blood platelet aggregation was decreased by kiwifruit supplementation.ConclusionGolden kiwifruit consumption strengthens resistance towards endogenous oxidative damage.

Highlights

Diets rich in fruits and vegetables offer protection against the development of cardiovascular diseases (CVD), diabetes and cancer [1,2,3]
Our results indicate that golden kiwifruit strengthens our resistance towards endogenous oxidative damage, but our results do not support the view that the golden kiwifruit provides noticeably stronger protection against oxidative damage than the green variety
Simple regression analysis was performed to evaluate correlation between plasma vitamin C and strand breaks. Both reduced ascorbic acid and total ascorbic acid increased after supplementation with kiwifruit (Table 1), reduced ascorbic acid being borderline significant (p = 0.054) and total ascorbic acid approaching statistical significance (p = 0.068) at 2 kiwifruits per day

Summary

Introduction

Diets rich in fruits and vegetables offer protection against the development of cardiovascular diseases (CVD), diabetes and cancer [1,2,3]. Hort 16A, differs significantly in phytochemical make-up (with 20% higher vitamin C content [9]), demonstrating higher FRAP values [16] than the green kiwifruit. Based on these properties the golden kiwifruit would be expected to show stronger protection against effects of oxidative damage in-vivo. To test this hypothesis, we conducted a human dietary intervention trial with golden kiwifruit, examining potential effects on platelet function, plasma antioxidant status, DNA oxidation, and base excision repair (BER), as well as nucleotide excision repair (NER) activity. The health positive effects of diets high in fruits and vegetables are generally not replicated in supplementation trials with isolated antioxidants and vitamins, and as a consequence the emphasis of chronic disease prevention has shifted to whole foods and whole food products

Methods

Results

Discussion

Conclusion