Sweet potato [Ipomoea batatas (L.) Lam. "Tainong 57"] starch improves insulin sensitivity in high-fructose diet-fed rats by ameliorating adipocytokine levels, pro-inflammatory status, and insulin signaling.
The aim of this study was to investigate the effects of low-glycemic index (GI) sweet potato starch on adipocytokines, pro-inflammatory status, and insulin signaling in the high-fructose diet-induced insulin-resistant rat. We randomly divided 24 insulin-resistant rats and 16 normal rats into two groups fed a diet containing 575 g/kg of starch: a low-GI sweet potato starch (S) or a high-GI potato starch (P). The four experimental groups were labeled as follows: insulin-resistant P (IR-P), insulin-resistant S (IR-S), normal P (N-P) and normal S (N-S). After 4 wk on the experimental diets, an intraperitoneal glucose tolerance test (IPGTT) was conducted, and the homeostasis model assessment (HOMA), adipocytokines, pro-inflammatory cytokines levels, and insulin signaling-related protein expression were measured. The homeostasis model assessment values were significantly lower in the IR-S than in the IR-P group, suggesting that insulin sensitivity was improved among sweet potato starch-fed rats. Levels of tumor necrosis factor-α, interleukin-6, resistin, and retinol binding protein-4 were significantly lower in the IR-S versus the IR-P group, indicating an improvement of pro-inflammatory status in sweet potato starch-fed rats. The sweet potato starch diet also significantly enhanced the protein expression of phospho-Tyr-insulin receptor substrate-1 and improved the translocation of glucose transporter 4 in the skeletal muscle. Our results illustrated that sweet potato starch feeding for 4 wk can improve insulin sensitivity in insulin-resistant rats, possibly by improving the adipocytokine levels, pro-inflammatory status, and insulin signaling.
School of Nutrition and Health Sciences, Taipei Medical University.
Ya-Yen
YY
Chen
Ming-Hoang
MH
Lai
Hsin-Yu
HY
Hung
Jen-Fang
JF
Liu
D000818:Animals; D004032:Diet; D004040:Dietary Carbohydrates / Q000378:metabolism / Q000494:pharmacology / Q000627:therapeutic use; D005632:Fructose / Q000009:adverse effects; D005951:Glucose Tolerance Test; D051275:Glucose Transporter Type 4 / Q000378:metabolism; D038321:Glycemic Index; D007249:Inflammation / Q000097:blood / Q000517:prevention & control*; D007328:Insulin / Q000378:metabolism*; D055504:Insulin Receptor Substrate Proteins / Q000378:metabolism; D007333:Insulin Resistance / Q000502:physiology; D015850:Interleukin-6 / Q000097:blood; D027723:Ipomoea batatas / Q000737:chemistry*; D008297:Male; D010936:Plant Extracts / Q000494:pharmacology / Q000627:therapeutic use; D035281:Plant Tubers; D051381:Rats; D017207:Rats, Sprague-Dawley; D052243:Resistin / Q000097:blood*; D054839:Retinol-Binding Proteins, Plasma / Q000378:metabolism; D015398:Signal Transduction; D013213:Starch / Q000378:metabolism / Q000494:pharmacology / Q000627:therapeutic use*; D014409:Tumor Necrosis Factor-alpha / Q000097:blood
D004040:Dietary Carbohydrates; D051275:Glucose Transporter Type 4; D007328:Insulin; D055504:Insulin Receptor Substrate Proteins; D015850:Interleukin-6; D010936:Plant Extracts; C532035:Rbp4 protein, rat; D052243:Resistin; D054839:Retinol-Binding Proteins, Plasma; D014409:Tumor Necrosis Factor-alpha; D005632:Fructose; D013213:Starch