Powdered Fruit and Vegetable Juice Concentrates Attenuate Carbonyl Proteins and TNF-alpha in Trained Men

Abstract

PURPOSE: The aim of this study was to assess the effects of supplementation over 7 months with an encapsulated juice powder concentrate (JPC: Juice Plus+®, Memphis, TN) or placebo on markers of oxidation and immune activation in men at rest and after a controlled exercise bout. METHODS: Trained men (n = 40, 34 ± 5 yrs, 55 ± 7mLkg-1 min-1, non smokers) from a homogenous population (Special Forces: Cobra) were randomly assigned in a double blind manner to either JPC (n = 20) or placebo (n = 20) after a four week washout period. The assigned treatment was taken as three capsules twice daily for 28 weeks. Exercise and blood sample collection were carried out after completion of wash out (baseline) and at study weeks 4, 8, 16 and 28. Capillary blood from finger-tip was collected before exercise (BE), immediately after the exercise test (IE), at 30 minutes (30M) and at 30 hours (30H) after each test. The exercise test was performed at 70% of VO2max (previously determined) until exhaustion at 80 rpm on a bicycle ergometer. Blood samples were analyzed for plasma carbonyl proteins (CP) and tumor necrosis factor alpha (TNF-alpha). Analysis used repeated measures ANO VA with p<0.05 considered significant. RESULTS: The CP concentrations after 16 and 28 weeks were significantly lower in the JPC group than in the placebo group (p<0.001) and lower than baseline for the JPC group (p<0.05). The exercise protocol had no effect on CP. TNF-alpha concentrations increased in both groups in the first 8 weeks (p<0.05) followed by a significant decrease in the JPC group for the next 20 weeks (p<0.0001). The values in the placebo group were unchanged during these 20 weeks compared to the first eight weeks. CONCLUSIONS: These data suggest that compared to placebo over 7 months, JPC protected plasma proteins and reduced immune activation as shown by CP and TNF-alpha. Increase of TNF-alpha after 8 weeks of study in both groups may be due to a documented common upper respiratory tract infection in the cohort at this time point. The model of exercise did not influence the measured variables in this trained population.