Metabolic Disease Symptoms are Reduced in C57BL/6J Mice Fed High‐fat Diets Supplemented with Oak Tannins

Abstract

Previous work has demonstrated that moderate red wine consumption, and intake of some bioactive compounds in wine including quercetin and resveratrol correlate with a reduced incidence of metabolic disease symptoms. The aging of wine in oak barrels adds to the polyphenolic content of wine by introducing oak tannins to the wine. Tannins have been suggested to be related to the hypothesized beneficial effect of wine against the progression of cardiovascular and metabolic disease.The objective of the present study is to investigate the influence of oak tannin intake on the symptoms of metabolic syndrome induced by the consumption of a high fat diet fed C57BL/6J (C57) mice. C57 mice were fed low fat (LF), high fat (HF), and HF containing 0.16% (w/w) of oak tannin powder (HF+OT) for 10 weeks. HF + OT intake significantly reduced body weight (42.4g±1.2g [HF] vs. 38.2g±1.4g [HF+OT]). Glucose homeostasis was regulated by OT intake, e.g., serum resistin levels were lower in HF+OT‐fed mice, compared to HF‐fed mice (374±11 pg/mL in HF vs.301±10 pg/mL). Further, hepatic lipid accumulation was lower in the HF+OT‐fed group (p<0.05). To further understand the underlying mechanisms of how OT intake regulates glucose and lipid metabolism, hepatic gene expression related to lipid, glucose, and xenobiotic metabolism was evaluated. Relative expression of Gstm2 was significantly decreased in the HF+OT group (p<0.05). Scd1 gene expression was increased in the HF‐fed group, and reduced to a value resembling the LF‐fed group in HF+OT fed mice. Nqo1 and Cyp2b10 gene expression was decreased with OT intake. Serum levels of the pro‐inflammatory cytokine MCP‐1, was marginally reduced HF+OT‐ vs. HF‐fed mice (p=0.0877).A follow‐up study was completed to determine whether the consumption of oaked vs. unoaked red wine can influence metabolic syndrome parameters in HF‐fed mice. In a ten‐week trial, mice were fed LF or HF diets, and HF diets with an oaked wine concentrate (HF+OWC) or unoaked wine concentrate (HF+UWC). Intake of both the HF+OWC and HF+UWC reduced body weight gain, compared to HF‐fed mice. Hepatic gene expression evaluation of Lipe, Cyp2b10, and Gsta showed more significant regulation of these mRNAs with intake of OWC vs. UWC.We conclude that intake of oak tannins have the potential to act as an agent to ameliorate symptoms of metabolic syndrome.Support or Funding InformationDesert Heart Foundation