Health Effects of 3-Day Fruit and Vegetable Juice Fasting

Abstract

Background: The gut microbiota is an important contributor to human health and has been implicated in the development of obesity and obesity-related diseases. Intermittent fasting has been shown to enhance weight loss. Fruit/vegetable juice-based cleansing practices are becoming popular. The juices provide polyphenols, oligosaccharides, and nitrate (beet juice), which may induce a prebiotic-like effect. Objective: The clinical trial determine whether a 3-d fruit/vegetable juice fast can increase beneficial gut bacteria leading to weight loss, increased antioxidant capacity, decreased oxidative damage, and improve general well-being. Methods: Twenty healthy subjects consumed only fruit/vegetable juices (Cold Pressed Juicery, Santa Monica, CA) according to a 3-d juice fast/cleansing protocol, followed by an 11-d low flavonoid diet. Blood, urine and stool were collected at days 0, 4, and 14. Plasma antioxidant activity (TEAC) and nitric oxide (NO), urine NO and malondialdehyde were analyzed. Intestinal microbial composition is being determined by sequencing of bacterial16S ribosomal RNA using MiSeq (Illumina, CA). Results: On day 4 we observed a significant decrease in weight and body mass index (BMI), which was maintained until day 14. Plasma and urine NO was significantly increased by 244 ± 89% and 450 ± 360%, respectively. Urinary lipid peroxidation marker malondialdehyde was decreased significantly by 32 ± 21% but plasma TEAC was not changed. All analytical markers returned to close to baseline values on day 14. Changes in the fecal microbiome will be presented. General well-being score was not changed at day 4 but was significantly decreased at the end of the study. Conclusions: The 3-d juice cleansing induced persistent weight loss. The juice fast decreased lipid peroxidation and increased NO concentrations, which may improve cardiovascular health.