Sa. Morgan et al., A LOW-FAT DIET SUPPLEMENTED WITH MONOUNSATURATED FAT RESULTS IN LESS HDL-C LOWERING THAN A VERY-LOW-FAT DIET, Journal of the American Dietetic Association, 97(2), 1997, pp. 151-156
Objective The purpose of this study was to compare the effects of a ve
ry-low-fat diet with a low-fat diet supplemented with monounsaturated
oil on plasma lipid levels in subjects with hypercholesterolemia. Desi
gn The 8-week study was divided into one 2-week baseline diet and two
3-week intervention periods in a randomized crossover design. Setting
The study was conducted in an outpatient setting at the Deakin Institu
te of Human Nutrition, Deakin University, Geelong, Australia. Subjects
Twenty-four free-living subjects with hypercholesterolemia participat
ed in and completed the study. Intervention After a 2-week baseline pe
riod of a self-selected diet, subjects were assigned to one of two die
tary interventions: a very-low-fat (10% of energy from fat), high-carb
ohydrate diet or a low-fat (26% of energy from fat) diet supplemented
with olive oil and an olive oil-based margarine. Main outcome measures
Lipid measurements included total cholesterol, low-density Lipoprotei
n cholesterol, high-density lipoprotein cholesterol, and triglyceride
concentrations. Plasma cholesteryl esters were measured to monitor com
pliance. Statistical analyses A paired t test was used to assess diffe
rences between treatment periods for each subject. The dependence of t
he difference between treatment periods on the covariates of age, sex,
initial cholesterol concentration, and energy intake was analyzed usi
ng repeated measures and analysis of covariance. Results The low-fat d
iet supplemented with monounsaturated fat resulted in significantly le
ss high-density Lipoprotein cholesterol lowering than the very-low-fat
diet (P=.005). Both interventions resulted in significant reductions
in both low-density Lipoprotein cholesterol and total cholesterol comp
ared with the baseline diet. Applications This study suggests that a l
ow-fat diet enriched with olive oil provides advantages over a very-lo
w-fat diet in the control of serum lipoproteins among persons with hyp
ercholesterolemia.