Original Research Supplementation with Mixed Fruit and Vegetable Juice Concentrates Increased Serum Antioxidants and Folate in Healthy Adults Ingrid Kiefer, PhD, Peter Prock, MD, Catherine Lawrence, BEng, John Wise, PhD, Wilfried Bieger, MD, Peter Bayer, MPsych, Theres Rathmanner, MSc, Michael Kunze, MD, Anita Rieder, MD Institute of Social Medicine, Department of Public Health, Medical University Vienna, Vienna, AUSTRIA (I.K., P.P., C.L., P.B., T.R., M.K., A.R.), Natural Alternatives International Research Foundation, San Marcos, California (J.W.), ANTOX Center, Munich, GERMANY (W.B.) Key words: antioxidant, phytonutrient, folate, fruit, vegetable Objective: Epidemiological studies have shown that low plasma levels of antioxidant micronutrients, which are commonly found in fruit and vegetables, are associated with increased risk for diseases such as heart disease, cancer, metabolic disorders and the like. The aim of this study was to monitor the dietary habits of a group of healthy, middle-aged, men and women and to assess the effect of supplementation with a natural phytonutrient preparation from fruits and vegetables, on plasma levels of various antioxidant micronutrients and oxidative stress assessed by measuring 8-oxodGuo (8-oxo-7,8-dihydro-2'-deoxyguanosine) in urine. Methods: The study followed a double-blind randomized cross-over design involving 59 healthy men and women (40 – 60 years of age). The supplement or a placebo was given to two groups for a total period of 14 weeks (crossover week 7). Blood levels of -carotene, vitamin C, vitamin E, selenium and folate were measured at 0, 7 and 14 weeks. Fruit and vegetable consumption was monitored by means of a retrospective food frequency questionnaire at week 0, 7 and 14. Urinary 8-oxodGuo was also determined at these time points. Results: Significant increases in blood nutrient levels after active supplementation were observed for -carotene, vitamin C, vitamin E, selenium and folate. Ranges measured, after supplementation, often fell into those associated with a reduced risk for disease. Our data suggests that, although generally health conscious, participants still fell short of the recommended five portions of fruit and vegetables per day. No significant group changes were noted for 8-oxodGuo concentration in urine. Conclusion: Supplementation with mixed fruit and vegetable juice concentrates effectively increased plasma levels of important antioxidant nutrients and folate. INTRODUCTION Epidemiological studies have shown the importance of a diet rich in fruit and vegetables in the prevention of illnesses, such as, heart disease, cancer, metabolic disorders and the like [1– 4]. Low plasma levels of micronutrients with antioxidant properties, often found in fruit and vegetables, are associated with increased risk for these diseases [5–7]. Recommendations for consumption of fruit and vegetables are currently given as five or more servings per day [8,9]. In reality, however, surveys have shown that these guidelines are rarely met [10,11]. In an effort to attain improved plasma levels of antioxidants, micronutrient supplementation has been sug- gested as a viable approach [12,13]. Previous intervention studies involving micronutrient sup- plementation have not always achieved the desired results [14,15]. It was reported that -carotene-supplemented smokers were found to have a slightly increased lung cancer mortality when compared to the group not receiving the -carotene supplement. The reason for this could be imbalanced adminis- tration of supplements. High doses of a single, synthetically produced, nutrient fail to consider the potential interactions and Address reprint requests to: Ingrid Kiefer, PhD, Institute of Social Medicine, Department of Public Health, Medical University Vienna, Rooseveltplatz 3, A-1090 Vienna, AUSTRIA. E-mail: ingrid.kiefer@meduniwien.ac.at Journal of the American College of Nutrition, Vol. 23, No. 3, 205–211 (2004) Published by the American College of Nutrition 205