Immune function in elderly smokers and nonsmokers improves during supplementation with fruit and vegetable extracts

Background: Epidemiological evidence suggests fruits and vegetables reduce the risk of cardiovascular disease (CVD) and cancer. Immune function declines with age as CVD and cancer incidence rises and may be related to poor antioxidant status. Objective: To investigate how fruit and vegetable extracts (Juice Plus(TM)) containing multiple antioxidants and phytonutrients affect immune function in the elderly. Design: Subjects (n = 53; aged 60-86 years, mean = 68 years) consumed extracts for 80 days and two blood samples were taken at baseline and then one at days 40 and 80. Results: Significant increases were found in the serum antioxidants when baseline values were compared with day 80; lutein/zeaxanthin (p < .005), α-carotene (p < .0001), β-carotene (p < .0001), lycopene (p < .05), and α-tocopherol (p < .005). Spontaneous proliferation of PBM cells increased significantly (p < .0001). Natural killer (NK) cell cytotoxicity significantly increased at effector to target cell ratios of 100:1 (p < .0001), 50:1 (p < .0005), and 25:1 (p < .005). Supernatant from PBM cells stimulated with phytohemaglutinin (PHA; 10 μg/mL) resulted in significant twofold increases in interleukin-2 (IL-2) (p < .0001). Additionally, statistically significant increases in IL-2 production were observed in smokers (p < .005). Conclusions: Fruit and vegetable extract supplementation significantly enhanced multiple measures of immune function in elderly subjects, and improved IL-2 levels in smokers. Fruit and vegetable extract supplementation offers a novel way to improve compliance with current nutritional recommendations and may potentially lower disease risk. Copyright (C) 1999 Elsevier Science Inc.