Health benefit of vegetable/fruit juice-based diet: Role of microbiome

Abstract

The gut microbiota is an important contributor to human health. Vegetable/fruit juices provide polyphenols, oligosaccharides, fiber and nitrate (beet juice), which may induce a prebiotic-like effect. Juice-based diets are becoming popular. However, there is a lack of scientific evidence of their health benefits. It was our hypothesis that changes in the intestinal microbiota induced by a juice-based diet play an important role in their health benefits. Twenty healthy adults consumed only vegetable/fruit juices for 3 days followed by 14 days of customary diet. On day 4 we observed a significant decrease in weight and body mass index (p = 2.0E^-05), which was maintained until day 17 (p = 3.0E^-04). On day 4 the proportion of the phylum Firmicutes and Proteobacteria in stool was significantly decreased and Bacteroidetes and Cyanobacteria was increased compared to baseline and was partially reversed on day 17. On day 4 plasma and urine nitric oxide was increased by 244 ± 89% and 450 ± 360%, respectively, and urinary lipid peroxidation marker malondialdehyde was decreased by 32 ± 21% compared to baseline. General well-being score was increased at the end of the study. In summary a 3-day juice-based diet altered the intestinal microbiota associated with weight loss, increase in the vasodilator NO, and decrease in lipid oxidation.

Figure 1

Effect of juice based diet on body weight (a) and body mass index (b). Data are mean ± SEM, n = 20. One way repeat measures ANOVA was performed. Difference to baseline is indicated; *p < 0.05.

Figure 2

Effect of juice based diet on fecal microbiota (phylum) comparing baseline (day 0), after the juice intervention (day 4) and after two weeks of customary diet (day 17). Values are mean ± SEM (n = 20). Difference to baseline is indicated by *p < 0.05.

Figure 3

Effect of juice based diet on urinary malondialdehyde concentration. Data are mean ± SEM. One way repeat measures ANOVA was performed. The difference to baseline is indicated **p < 0.001.

Figure 4

The effect of juice based diet on (a). Plasma nitric oxide and (b). Urinary nitric oxide. Data are mean ± SEM (n = 20). One way repeat measures ANOVA was performed. The difference to baseline is indicated ***p < 1.0E⁻⁰⁸.

Figure 5

Effect of juice based diet on Wellness Score. Data are mean ± SEM (n = 20). One way repeat measures ANOVA was performed. The difference to baseline is indicated *p < 0.05.