A simple dietary intervention to reduce inflammation and oxidative stress in individuals with metabolic syndrome

Abstract

Abstract Funding Acknowledgements Type of funding sources: None. Background Approximately 25% of the world's population have metabolic syndrome and those diagnosed have a two-fold risk of developing cardiovascular disease. Inflammation and oxidative stress are responsible for the pathogenesis of metabolic syndrome. Diets with a high intake of vegetables containing carotenoids, a type of antioxidants, are associated with reduced levels of inflammation and oxidative stress, yet interventions to increase vegetable intake have been difficult to adapt. We conducted a randomized controlled trial of a simple dietary antioxidant intervention to reduce the levels of inflammation and oxidative stress. Purpose To examine the effect of a simple dietary antioxidant intervention on levels of inflammation and oxidative stress in persons with metabolic syndrome. Methods A total of 93 individuals with metabolic syndrome (mean age 61 ± 12 years old, 71% female) were enrolled. The intervention group received an 11.5-ounce serving of 100% carotenoid-rich vegetable juice to consume once per day for 30 days. The control group maintained their normal dietary pattern for 30 days. Adherence to the intervention was measured with Veggie Meter®, a validated reflection spectroscopy approach to assess skin carotenoid levels. Inflammation and oxidative stress were measured by plasma levels of high-sensitivity C-reactive protein (CRP) and malondialdehyde (MDA) at baseline and one-month post intervention. Two-way repeated measures analysis of variance was used to compare the group means over time. Log-transformation was applied as necessary for the variables with skewed distribution. Results There was no significant interaction between treatment and time on skin carotenoid levels, (respectively, P=0.214). There was a statistically significant increase of skin carotenoid levels in the intervention group alone (220 vs 264 in pre and post intervention, respectively, P=0.002). Change in mean CRP levels did not differ between control and intervention groups (P=0.520). Similarly, change in mean MDA did not significantly differ between two groups (P = 0.450). Conclusion A simple and easy to adapt, 1-month dietary antioxidant intervention did not change levels of inflammation and oxidative stress in individuals with metabolic syndrome, potentially due to the short-term treatment. Future interventions with dietary antioxidants should be implemented for longer time periods to fully assess the impact on inflammation and oxidative stress.