低升糖指數飲食對於體重過重或肥胖女性體組成及脂質代謝之影響

Effect of Low Glycemic Index Diet on Body Composition and Lipid Metabolism of Overweight or Obese Women

本研究為給予體重過重或肥胖女性不同升糖指數 （Glycemic index, GI） 之食材介入，探討對於體組成及血脂之影響，並進一步了解其影響機制為何。實驗分成兩階段進行： （ 一） 招募15 位健康受試者，進行食材GI 值測定，選擇較低GI 值者為飲食介入期之介入食材 （ 二） 招募20 位過重或肥胖女性，給予不同GI 值食材，探討其對於體組成及脂質代謝之影響，此部分採隨機交叉試驗，分為正常飲食 （Normal diet, ND） 組與低升糖指數飲食 （Low-GI diet, LGI） 組。飲食介入期為6週，於飲食排空期後，兩組交換飲食進行相同流程。飲食介入期前後收集飲食記錄、採集空腹血液樣本以進行血脂、血糖、胰島素及相關脂質代謝酵素之蛋白質表現量等之分析，並以雙能量X光吸收儀 （dual energy X-ray absorptiometry, DEXA） 進行體位測量。結果顯示，飲食介入前後相比，LGI 組飲食中膳食纖維攝取量顯著增加；ND 組體重與身體質量指數 （body mass index, BMI） 顯著上升，而LGI 組臀圍、總膽固醇及低密度脂蛋白膽固醇濃度顯著下降，並且LGI 組中賀爾蒙敏感性脂解酶 （hormone-sensitive lipase, HSL） 蛋白質表現量顯著上升，上升幅度為193%。由此可知，給予過重或肥胖女性6 週低GI 值飲食介入，可顯著降低體內總膽固醇及低密度脂蛋白膽固醇濃度並且可提昇體內HSL 之蛋白質表現量。

The aim of this study was to investigate the effects of different glycemic index (GI) food intervention on the lipid profiles and body composition of overweight or obese women. The study was composed of two parts. In part 1, fifteen healthy subjects were recruited to measure the GI values of tested food. Low GI food were chosen to apply in the part 2. Part 2 was a randomized, cross-over and controlled　clinical trail. Twenty women were recruited. The included criteria were body mass index (BMI) higher than 24 kg/m2, and matched the either one mentioned below: fat mass ≧ 30% or waist circumference > 80 cm. After run-in period, subjects were divided into normal diet (ND) group or low-GI diet (LGI) group randomly; and the experimental period was lasted for 6-wk. A 2-wk wash-out period existed between each diet intervention. Diet records, body composition data by dual energy X-ray absorptiometry (DEXA) and fasting blood samples were collected before and at the end of each diet period for further analysis. In addition, the protein expressions of lipogenetic and lipolytic enzyme were measured. The results showed that the intake of dietary fiber increased over time in LGI group compared to that at 0 week. Body weight and BMI increased significantly over time in ND group, and the hip circumference decreased significantly over time in LGI group. In addition, the levels of total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) in plasma decreased significantly over time in LGI group. The protein expression of hormone-sensitive lipase (HSL) was upregulated markedly over time in LGI group. These results suggest that consumption of LGI grains for 6-wk could decrease blood TC and LDL-C levels and increase the protein expression of HSL in overweight or obese women.