Key result
Purple grape juice supplementation for 4 weeks did not improve endothelial function compared with clear apple juice in childhood cancer survivors (difference of mean change -0.16; P=0.25).
Why the study?
Does purple grape juice improve microvascular endothelial function in childhood cancer survivors?
RCT (n=24)
randomized
Does purple grape juice improve microvascular endothelial function in childhood cancer survivors?
Four weeks of daily flavonoid-rich purple grape juice supplementation did not improve microvascular endothelial function or markers of oxidative stress and inflammation in childhood cancer survivors.
Does not support purple grape juice supplementation to improve endothelial function in childhood cancer survivors; confirms lack of short-term benefit in this RCT.
BACKGROUND: Childhood cancer survivors have an increased risk of developing cardiovascular disease following treatment, yet few interventions have been evaluated to reduce this risk. Purple grape juice (pGJ), a rich source of flavonoids with antioxidant properties, has been shown in adults to reduce oxidative stress and improve endothelial function. We examined the effects of supplementing meals with pGJ on microvascular endothelial function and markers of oxidative stress and inflammation in 24 cancer survivors (ages 10-21 years). PROCEDURE: In a randomized controlled crossover trial consisting of two, 4 week intervention periods, each preceded by a 4 week washout period, subjects received in random order 6 ounces twice daily of pGJ and clear apple juice (cAJ; similar in calories but lower in flavonoids). Measurements were obtained before and after each supplementation period; change was evaluated using mixed effects ANOVA. RESULTS: pGJ did not improve endothelial function, measured using digital reactive hyperemia, compared with cAJ (mean change: pGJ 0.06, cAJ 0.22; difference of mean change [95% CI]: -0.16 [-0.42 - 0.11], P = 0.25). No significant changes in plasma concentrations of oxidized-LDL, myeloperoxidase, or high sensitivity C-reactive protein were observed. CONCLUSION: After 4 weeks of daily consumption of flavonoid-rich pGJ, no measurable change in vascular function was observed in these childhood cancer survivors.
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Blair et al. (2014) conducted an RCT in childhood cancer survivors (n=24). purple grape juice vs. clear apple juice was evaluated on endothelial function measured using digital reactive hyperemia (MD -0.16, 95% CI -0.42 - 0.11, p=0.25). Purple grape juice supplementation for 4 weeks did not improve endothelial function compared with clear apple juice in childhood cancer survivors (difference of mean change -0.16; P=0.25).
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