Aziz Alfred, Xiao Chao Wu, Cockell Kevin A, Sarwar Gilani G, Cruz-Hernandez Cristina, Nimal Ratnayake W M
Nutrition Research Division, Food Directorate, Health Products and Food Branch, Health Canada, PL 2203E, 251 Sir Frederick Banting Driveway, Ottawa K1A 0K9, ON, Canada.
Br J Nutr. 2008 Sep;100(3):503-11. doi: 10.1017/S0007114508911521. Epub 2008 Jan 29.
This study tested the hypothesis that protein source is a factor determining the impact of the diet on lipid metabolism in hamsters. Twenty-eight hamsters of similar body weight were assigned for a period of 8 weeks to one of the following four diets (seven per group) containing either 20 % (w/w) casein (CAS), beef protein (BF), wheat gluten (WG) or soya protein (SOY). The fat composition of the diet was the same (15.5 % w/w) in all groups and provided SFA, MUFA and PUFA representative of the average Canadian diet. After an overnight fast, blood and liver were collected for the measurement of serum lipids, fatty acid composition of liver phospholipids and mRNA levels of selected genes involved in lipid metabolism. WG resulted in lower total cholesterol, HDL-cholesterol and non-HDL-cholesterol but, along with SOY, in higher mRNA levels of cholesterol 7 alpha-hydroxylase and LDL receptor. Furthermore, both WG and SOY resulted in lower 18 : 3n-3, 20 : 4n-6, total n-6 PUFA, 18 : 1n-9 and total MUFA, but higher 22 : 6n-3, total n-3 PUFA, 22 : 6n-3/18 : 3n-3 and 22 : 5n-3/18 : 3n-3 ratios in liver phospholipids, and higher hepatic Delta6-desaturase mRNA levels. These results show that the impact of dietary protein on lipid metabolism is source-dependent and associated with changes in mRNA abundances of key hepatic enzymes and receptors.
蛋白质来源是决定饮食对仓鼠脂质代谢影响的一个因素。将28只体重相近的仓鼠分配至以下四种饮食之一（每组7只），为期8周，这些饮食分别含有20%（w/w）的酪蛋白（CAS）、牛肉蛋白（BF）、小麦麸质（WG）或大豆蛋白（SOY）。所有组饮食中的脂肪组成相同（15.5% w/w），提供了代表加拿大平均饮食的饱和脂肪酸、单不饱和脂肪酸和多不饱和脂肪酸。禁食过夜后，采集血液和肝脏用于测定血清脂质、肝脏磷脂的脂肪酸组成以及参与脂质代谢的选定基因的mRNA水平。WG导致总胆固醇、高密度脂蛋白胆固醇和非高密度脂蛋白胆固醇水平较低，但与SOY一样，胆固醇7α-羟化酶和低密度脂蛋白受体的mRNA水平较高。此外，WG和SOY均导致肝脏磷脂中18 : 3n-3、20 : 4n-6、总n-6多不饱和脂肪酸、18 : 1n-9和总单不饱和脂肪酸水平较低，但22 : 6n-3、总n-3多不饱和脂肪酸、22 : 6n-3/18 : 3n-3和22 : 5n-3/18 : 3n-3比值较高，并且肝脏Δ6-去饱和酶mRNA水平较高。这些结果表明，膳食蛋白质对脂质代谢的影响取决于来源，并与关键肝脏酶和受体的mRNA丰度变化有关。
