Type II diabetes (T2D) arises through insulin resistance and a progressive decrease in insulin secretion, which may be partly related to pancreatic beta-cell function decline, obesity, and eventual hyperglycemia [1] . The first line for managing hyperglycemia in patients with T2D includes lifestyle modifications and metformin monotherapy. However, many patients still showed poor glycemic control due to progressive deterioration during the course of T2D [2 , 3] . On streptozotocin-induced T2D rats, tempeh fermentation has been shown to be a potentially beneficial dietary supplement for abnormal carbohydrate metabolism [4] . This study was a prospective open-label clinical trial. The data were collected from Kaohsiung Veterans General Hospital Pingtung Branch, Taiwan from August 2018 to July 2019. 35 eligible T2D participants with a mean age of 57.91 ± 10.17 years were enrolled. After taking 2 g tempeh capsules daily for a period of 3 months, the levels of HbA1C and triglyceride were noticeably decreased in the participants. A regression analysis revealed that cholesterol concentration had a significant positive correlation with the concentrations of LDL, but triglyceride concentration had a significant negative correlation with the concentrations of HDL in the pre- and the post-tempeh treatment.

Studies suggest that the consumption of Tempeh can improve abnormal blood glucose and lipid parameters, although it remains still unclear as to whether Tempeh can improve tissue damage. In our study, db/db obese diabetic mice were given Tempeh 1 (300 mg/kg) and Tempeh 2 (600 mg/kg) for 3 months. The tissue samples collected were stained using different tissue‐staining methodologies and were compared with the diabetic control group that was not given any Tempeh. Our results demonstrated that consuming high‐dose Tempeh for 1 month could significantly reduce serum glucose and body weight in mice whereas the tissue section of our result could validate that consuming high‐dose Tempeh for 3 months effectively improves lipid droplet size and lipid accumulation in the liver, aorta, and kidney of the mice. Moreover, an indication of the recovery of the damaged tissue could be observed in the heart and pancreatic tissue when high dosage of Tempeh was given as a treatment. Thus, it can be concluded that continuous consumption of Tempeh as a treatment could improve both blood glucose and body weight of diabetic mice while also improving lipid accumulation and tissue damage.