THE INFLUENCE OF DAIRY-PRODUCTS ON PLASMA URIC-ACID IN WOMEN

Elevated levels of plasma uric acid have been linked to increased risk of cardiovascular diseases and their complications. As dairy proteins have been found to decrease plasma uric acid without increasing glome rular filtration rate, a sample of postmenopausal women living in Mont real was studied to investigate the nature of this relationship. Parti cipants (158 Roman Catholic nuns) were randomly assigned to one of two test diets for a period of four weeks: the dairy foods group (n = 81) consumed approximately 30 grams of dairy protein daily and the dairy- free diet group (n = 77) ate no dairy foods at all. Subjects completed two one-day food records, a core questionnaire and a dairy foods diet history; blood specimens were obtained, and blood pressure, height an d weight were measured. Average nutrient intakes differed as a consequ ence of the test diets, with significantly greater intakes of protein, fat, saturated fat, monounsaturated fat, potassium and calcium (p < 0 .01) in the dairy group after the study period, and lower dietary leve ls of protein, cholesterol, calcium and retinol (p < 0.01) in the dair y-free group. Plasma uric acid was unchanged after the dietary interve ntion in the dairy group, but increased by 7.8 mu mol/l (p = 0.03) in subjects on the dairy-free diet; however, diastolic blood pressure dec reased in response to calcium (beta = -22.9, SE = 10.0, p = 0.02) amon g those whose diet included dairy foods. The study results suggest tha t proteins of dairy origin may play a role in stabilising or lowering plasma uric acid, and that calcium or other components found in milk p roducts may also reduce diastolic blood pressure. While these findings have implications for dietary prevention to decrease cardiovascular r isk in postmenopausal women, further investigations should examine the se mechanisms in men over the age of 50 to ascertain whether a similar response would occur.