Immunity and antioxidant capacity in humans is enhanced by consumption of a dried, encapsulated fruit and vegetable concentrate

Nantz MP, Rowe CA, Nieves C Jr, Percival SS; Oct. 2006


The goal of this study was to determine if a commercially available encapsulated fruit and vegetable juice powder concentrate (FV) could improve antioxidant status and markers of immune function and lessen DNA damage in a young adult population under stress. 


In this double-blind, placebo-controlled trial, a total of 59 healthy law school students were randomized to take either the encapsulated fruit and vegetable juice powder concentrate (Juice Plus+®) or placebo capsules for 11 weeks. Blood samples were analyzed for levels of antioxidants, markers of immune function (gamma-/delta T-cells), and lymphocyte DNA damage on days 1, 35, and 77. In addition, participants kept a log of any illnesses and symptoms.  


By day 77, blood levels of various antioxidant micronutrients and phytonutrients ― including beta-carotene, lycopene, and lutein ― were significantly increased among those taking the juice powder supplement compared to placebo. In addition, the percentage of gamma-delta T cells was significantly elevated in the FV group; however, there was no change in the placebo group. There was also a trend among those taking FV to have fewer total symptoms of illness. Finally, at baseline, there was greater DNA damage among people assigned to the intervention group than the placebo group. By day 35, however, the DNA damage in the groups was equal, indicating that FV lessens DNA damage. 


The formulation of the FV was effective in raising carotenoid levels, ascorbic acid levels, and plasma antioxidant capacity and was associated with a greater percentage of gamma-delta-T cells and the tendency for a reduced number of symptoms and duration of illness. 

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