Milk product and constituent protein effects on plasma and hepatic lipids and systolic blood pressure of normotensive rats

Abstract

The effects of diets containing casein (C), whey protein concentrate (W), skim milk protein concentrate (MPC), and yogurt powder (Y) on plasma total cholesterol, triacylglycerides and HDL-cholesterol (HDL-C), hepatic total lipids and cholesterol levels were studied in normotensive Wistar rats. Systolic blood pressure (SBP) was recorded weekly from 6 to 10 weeks of age. Diet effects were compared to animals fed soy protein isolate (S) and rat chow (RC) diets. Animals were meal fed until 10 weeks of age, when blood and liver tissue samples were collected. All groups exhibited similar growth rates. Animals fed C, W, MPC and S diets exhibited similar plasma triacylglycerides and total cholesterol levels, which were higher ( p ≤ 0·05) than in Y and RC animals. HDL-C was higher ( p ≤ 0·05) in C, W and MPC fed animals, than those fed Y or RC. HDL-C in S fed animals only approached a significantly ( p ≤ 0·07) lower amount compared to C, W and MPC fed animals. Hepatic total lipids and cholesterol were not significantly ( p > 0·05) different between groups. The small changes in plasma lipids observed in animals fed dairy products had little effect on SBP in normotensive rats.