Sunmin Park
Hoseo University, South Korea
Title: Phytochemicals produced by fermenting Korean foods, prevent and alleviate metabolic diseases by modulating the insulin signaling pathway
Biography
Biography: Sunmin Park
Abstract
Metabolic diseases such as diabetes, hypertention, dyslipidemia, obesity, stroke, retinopathy, myocardial infarction and neurodegeneration are interrelated with increased insulin resistance by attenuated insulin signaling in different tissues. Type 2 diabetes occurs when β-cell dysfunction develops simultaneously and as a consequence of insulin resistance increasing in the liver and skeletal muscles. Since Asians have lower insulin secretion capacity and β-cell mass, their susceptibility to develop type 2 diabetes is higher than in Caucasians. There is some evidence that hepatic insulin resistance is connected to brain insulin resistance, especially, in the hypothalamus. In addition, β-amyloid accumulation in the hippocampus results in cognitive dysfunction and exacerbates hepatic insulin resistance and glucose metabolism. Traditional Korean dietary and lifestyle patterns have contributed to a low incidence of insulin resistance and diabetes in the past. However, the westernization of the modern Korean lifestyle has increased the incidence of insulin resistance that cannot be compensated for by increased insulin output due to low β-cell function.
Korean fermented foods have enhanced bioactivitities over the original foods. For example, soybeans contain various phytoestrogens that improve energy, glucose and bone metabolism. However, their bioavailability is low. Fermentation changes the structure of phytoestrogens to form isoflavonoid aglycones, DDMP soyasaponin βg, E soyasaponin Be and lysoposphatidylcholines. These fermentation products are absorbed better in the gut and exhibit enhanced functionality for metabolism. Bioactivities of fermented foods are modified by the major microorganisms that ferment them. Soybeans are traditionally fermented with Bacillus licheniformis (chungkookjang) and Aspergillus oryzae (meju), without added salt, improve insulin sensitivity and insulinotropic actions better than unfermented soybeans in non-obese type 2 diabetic rats fed high fat diets. This improvement is associated with potentiating insulin signaling in the liver and pancreatic islets. Chungkookjang made with Bacillus licheniformis decreases the accumulation of β-amyloid deposits in rats with β-amyloid (25-35) infusion into the CA1 region. Therefore, traditional Korean fermentation of soybean foods improves their bioactivities for alleviating metabolic diseases, especially type 2 diabetes and Alzheimer’s disease.