Blueberry supplementation attenuates oxidative stress within the monocytes and modulates immune cell levels in adults with Metabolic Syndrome

Abstract

Background and rationaleBlueberries (BB) have been shown to have extensive health benefits in animals, including improvement of mitochondrial integrity, inflammation and redox status. In addition, we have found that BB improves insulin sensitivity in obese, pre‐diabetic humans and rodents, and decreases oxidative stress and inflammation, and protects against cardiovascular and renal damage in rodents. These findings indicate that BB have a whole body effect and are not limited to a particular organ system. In order for BB to exert beneficial effects on the whole body, the mechanism would logically have to operate through modulation of cellular humoral factors. The blood leukocytes are important cells protecting against injury or infection. The present study investigated the role of BB in modulating cellular humoral factors in subjects with metabolic syndrome (MetS).MethodA placebo‐controlled study was conducted on adults with MetS, where they received a BB or placebo smoothie twice daily for six weeks. Free radical production in the whole blood and monocytes, dendritic cells (DC) measurement, gene expression levels of cytokines in monocytes and serum inflammatory marker levels were assessed pre‐ and post‐intervention. MetS patientsResultsBaseline free radical levels in the whole blood and monocyte of MetS patient samples were not different in both groups.. In contrast, treatment with BB markedly decreased superoxide and total ROS in the whole blood and monocytes compared to placebo treated MetS patients samples (p<0.05). Next we examined the dendritic cell number and inflammatory markers in the blood of MetS patients. There was no significant difference in the baseline DC number for both myeloid and plasmatoid DCs in MetS patients samples. Treatment with blueberries markedly increased myeloid DC and had no effect on plasmatoid cells. In addition, BB treatment also decreased monocyte and plasma inflammatory molecules in MetS patients when compared with placebo treated controls. These findings indicate that BB exerts immuno‐modulatory effects, in addition to its antioxidant and anti‐inflammatory effects, thereby protecting against MetS.ConclusionsBlueberries modulates immune cells and attenuate oxidative stress and inflammation in the blood of MetS patients.Support or Funding InformationThis work was supported by U.S. Highbush blueberry council (USHBC) grant to Dr. Francis.