The impact of cheese consumption on markers of cardiovascular risk in rats

Abstract

We examined the influence of cheddar cheese compared with beef meat/tallow and casein/canola oil diets on biomarkers of cardiovascular health, using male Sprague Dawley laboratory rats. The total omega 3 (ω3) fatty acid content of cheese was 50% higher than that of tallow, and 20% higher than that of canola oil diets. Diets were designed to simulate a ‘western style’ diet (high fat/low protein/low calcium). Diets were balanced for energy and major nutrients, and contained 17.6% (w/w) fat and 13.7% protein, except for the 50% cheese diet, which had higher total cholesterol and calcium. We observed significantly lower plasma total cholesterol and non-HDL (LDL, IDL VLDL) cholesterol concentrations (−46%) and higher plasma triglyceride concentrations (+50%) in the 50% cheese diet-fed rats than in the beef meat/tallow-fed rats. The amount of triglyceride in rat livers was about 30% higher in the casein+tallow and beef meat+tallow-fed rats than in the other treatments. Fatty acid content of the liver triglycerides showed lower 18:1 and higher ω3 fatty acids: 18:3 (α-linolenic), 20:5 (eicosapentaenoic) and 22:6 (docosahexaenoic) in the cheese-fed than the tallow-fed rats, these concentrations being equivalent to that of the canola oil-fed rats. Liver triglyceride arachidonic acid (20:4) concentration was comparable between the cheese and canola oil sources of fat, but lower in the tallow-fed rats. These concentrations could be interpreted as indicating a good balance between the ω3 and ω6 long-chain precursors of eicosanoids responsible for significant biological effects, and representing a healthier fatty acid profile in cheese-fed animals than with the other dietary treatment groups. Other markers examined showed no significant deleterious effects associated with cheese consumption. The evidence in this rat study suggests that the fat derived from cheese could offer some significant benefits to health, as shown by the long-chain ω3 fatty acid composition of liver triglycerides and their known benefits to health.