Resistant starch promotes vitamin D balance and maintenance of methyl group metabolism in type 1 diabetic rats (1041.8)

Abstract

Type 1 diabetes mellitus (T1DM) is an autoimmune disease characterized by pancreatic beta cell dysfunction, insulin deficiency and abnormal carbohydrate metabolism. Chronic hyperglycemia causes structural damage to the kidneys, resulting in ultrafiltration and imbalance of nutrients such as vitamin D and disruption of various proteins associated with methyl group metabolism and homocysteine regulation. Using streptozotocin (STZ)‐treated rats as a model of T1DM, we have demonstrated that dietary resistant starch (RS) attenuates many complications associated with T1DM including increased urinary excretion of 25,OH vitamin D and vitamin D binding protein. The focus of this study was to further characterize the impact of RS on vitamin D balance and methyl group metabolism in diabetic rats. Female rats (n=36) were randomly assigned to 1 of 3 groups: control, T1DM and T1DM + dietary RS. Control and T1DM rats were fed a standard cornstarch diet during the 8‐wk treatment period, whereas T1DM + RS groups were fed a high amylose cornstarch diet (36% resistant to digestion). T1DM rats exhibited polyuria, hyperglycemia, decreased urinary creatinine excretion (2.3 fold) and increased hepatic (1.2 fold) and renal (~2 fold) GNMT activity. Dietary RS attenuated these complications. Future research will focus on understanding the mechanism by which dietary RS promotes regulation of vitamin d and methyl group metabolism. Body characters no spaces: 1217 / Body characters with spaces: 1428 Total characters no spaces: 1455 Grant Funding Source: Supported by Plant Sciences Institute, Iowa State University