Effects on Cholesterol Balance and LDL Cholesterol in the Rat of a Soft-Ripened Cheese Containing Vegetable Oils
Alexandrine During, PhD, Nicole Combe, PhD, Stephane Mazette, MD, and Bernard Entressangles, PhD
Laboratoire de Lipochimie Alimentaire, Département de Biologie, Université de Bordeaux I, Talence Cedex, FRANCE E-mail: during@bhnrc.arsusda.gov
Objective: The purpose of this study was to examine effects of a modified soft-ripened cheese containing vegetable oils on cholesterol status, using the rat as the experimental model and the traditional soft-ripened cheese as the control.
Methods: Adult male Wistar rats ( 370 g) were divided into two dietary groups (20 rats/group) and fed either the standard diet (STD, containing traditional cheeses made from whole milk) or the experimental diet (EXP, containing modified cheeses made from the combination of skim milk with the following fat mixture: milk fat/oleic acid-enriched sunflower oil/soybean oil mixture). Lipids of the diets came solely from cheeses (14 g/100 g diet); the EXP diet contained (3-fold) less saturated fat, (2-fold) less cholesterol, and (15-fold) more phytosterols than the STD diet.
Results: Although serum triglyceride and total cholesterol concentrations were not affected by the type of diet, the EXP diet resulted in a significant reduction of LDL-cholesterol (31%, p<0.001) and a significant increase of HDL-cholesterol (11%, p<0.05), compared to the STD diet. Thus, a marked reduction (39%) of serum LDL/HDL cholesterol ratio was observed in the EXP group (p<0.001). In addition, the two quantitative balances (excreted/ingested) of cholesterol and total neutral steros (for which phytosterols were excluded) were significantly higher by 183% and 174%, respectively, for the EXP group, compared to the STD group (p<0.05). On another hand, rats fed the EXP diet excreted more cholesterol than they ingested dietary cholesterol (cholesterol balance > 1), indicating that those animals eliminated some endogenous cholesterol in their feces, while the opposite was true for rats fed the STD diet (cholesterol balance < 1). Finally, fecal bile salt concentration was not significantly different between the two dietary groups.
Conclusions: The partial substitution of milk fat by vegetable oils in soft-ripened cheese resulted in a decreased blood LDL/HDL cholesterol ratio and an increased fecal excretion of endogenous cholesterol and neutral sterols and, thus, markedly improved its nutritional qualities. Therefore, the consumption of the described modified cheese may meet the demand of subjects who wish to lower their risk for atherosclerosis and cardiovascular disease.