Replacing cows' with sheep's dairy fat lowers plasma cholesterol concentration in participants consuming dairy fat-rich diets.

OBJECTIVE

To determine the effects on plasma cholesterol concentration of replacing cows' dairy fat with sheep's dairy fat.

DESIGN

Randomised crossover dietary intervention.

SETTING

General community, Dunedin, New Zealand.

SUBJECTS

Volunteer sample of 41 healthy adults with initial plasma cholesterol concentration between 4.8 and 7.8 mmol/l.

INTERVENTIONS

Participants were asked to follow a self-selected low-fat background diet throughout the study to which, during each of the 2, 3-week dairy diets, they were asked to add sheep's or cows' dairy products.

MAIN OUTCOME MEASURES

Energy and nutrient intakes, plasma triacylglycerol fatty acids, and plasma cholesterol.

RESULTS

Energy and nutrient intakes on the sheep-dairy and cow-dairy diets were very similar, with total, saturated, monounsaturated and polyunsaturated fat contributing 34, 18-19, 9, and 3% of total energy intake, respectively. Participants consumed approximately 50 g/day of dairy fat on each diet. Replacing cows' with sheep's dairy fat led to a 0.33 (0.11-0.56, 95% CI) mmol/l decrease (6%) in plasma total cholesterol concentration, from 5.53 (0.90, s.d.) to 5.20 (0.90) mmol/l. Plasma low-density lipoprotein (LDL) cholesterol was 0.18 (0.02-0.33) mmol/l lower on the sheep-dairy diet as was the concentration of plasma high-density lipoprotein (HDL) cholesterol, 0.11 (0.02-0.20) mmol/l. The LDL to HDL cholesterol ratio at the end of the sheep-dairy diet, 2.91 (1.10), was not significantly different (P>0.05) from the cow-dairy diet, 2.73 (0.83).

CONCLUSIONS

Within the context of a diet high in dairy fat (50 g/day), replacing cows' milk fat with sheep's milk fat leads to a small reduction in plasma cholesterol concentration, but no change in the ratio of LDL to HDL cholesterol.