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Maintenance of Vitamin D Status in Zucker Diabetic Fatty Rats by Dietary Resistant Starch is Dependent on Colonic Fermentation
Author(s) -
Koh Gar Yee,
Leow Shu En,
Reed Leah,
Wisecup Emily,
Rowling Matthew
Publication year - 2015
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.29.1_supplement.758.6
Subject(s) - medicine , endocrinology , resistant starch , type 2 diabetes , butyrate , diabetes mellitus , vitamin , vitamin d and neurology , chemistry , starch , food science , fermentation
Diabetic nephropathy increases the risk for vitamin D (VD) deficiency due in part to the role of kidney in maintaining circulating 25‐hydroxycholecalciferol (25D) concentrations. We reported that high‐amylose maize that is partially resistant to digestion (RS) protected renal health and maintained VD status in Zucker diabetic fatty rats (ZDF), an experimental model of type 2 diabetes. Here, we tested whether butyrate, a fermentation product of RS, underlies the renal protection in ZDF by comparing the effect of orally administered sodium butyrate (SB) with dietary RS. Lean Zucker (n=5) rats were fed AIN‐93G diet; ZDF (n = 5/group) were fed either AIN‐93G diet, AIN‐93G diet with SB at 2g/kg orally on alternate days, or AIN‐93G diet where cornstarch was replaced by RS for 7 weeks. SB suppressed body weight gain in ZDF whereas RS normalized their growth pattern, independent of hyperglycemia. Albuminuria and proteinuria were attenuated by RS and SB, respectively. However, RS, but not SB, prevented urinary excretion of the VD‐binding protein complex and 25D in ZDF, which resulted in 20% greater serum 25D concentrations compared to ZDF control. Additionally, serum triglycerides (TG) in ZDF control were 2‐fold higher despite hepatic TG being 50% lower compared with RS‐fed ZDF, while no differences were detected in SB‐treated ZDF. These data may further suggest that renoprotection in ZDF by SB and RS is driven by different mechanisms and that the regulation of VD metabolism and hepatic lipid mobilization in ZDF by RS could be dependent on colonic fermentation.