Exchanging carbohydrates for monounsaturated fats in energy-restricted diets: effects on metabolic profile and other cardiovascular risk factors.
OBJECTIVE
To investigate whether improvements in cardiovascular risk factors, as observed in energy-balance conditions after exchanging carbohydrates (CHO) for monounsaturated (MUFA) fats, are also observed in energy-restricted conditions.


METHODS
Longitudinal, clinical intervention study using two types of energy-restricted diets (-30% of initial energy intake) with similar levels of saturated and polyunsaturated fats: a high CHO diet (55% of energy from CHOs, 10% from MUFAs) and a high MUFA diet (40% of energy from CHOs, 25% from MUFAs).


METHODS
A total of 32 overweight subjects (nine males, 23 females, BMI: 26-45 kg/m(2)).


METHODS
Body weight, serum lipids, fasting plasma insulin and phospholipid fatty acid composition of red blood cells were measured at baseline and after 8 weeks. Various oxidative status parameters (plasma lipid hydroperoxides, total plasma antioxidant capacity, plasma uric acid and vitamin E) and serum-induced smooth muscular cell (SMC) proliferation were also measured at these time points.


RESULTS
Weight loss (1.1 kg/week over the first 4 weeks and 6.7 kg at week 8) was not significantly affected by the diet composition. Both diets reduced significantly total serum cholesterol, but the MUFA-rich diet showed better effects on fasting serum triacylglycerol (TG) than the CHO-rich diet: 1.18 vs 1.51 mmol/l for the MUFA-rich diet (after vs before, P<0.05) and 1.42 vs 1.62 for the CHO-rich diet. After 8 weeks, plasma vitamin E concentrations were positively associated with the oleic acid level of red blood cell phospholipids and showed opposite variations in both diets (increase with the MUFA-rich diet and decrease with the CHO-rich diet). Relative changes in SMC proliferation induced by sera were negatively associated with the ratio oleic:linoleic acid of red blood cell phospholipids and were significantly higher with the CHO-rich diet.


CONCLUSIONS
The MUFA-rich diet showed better effects on serum TG than the CHO-rich diet, even with energy restriction and weight loss. The results suggest also a protective effect of oleic acid on oxidative stress and SMC proliferation, two other important cardiovascular risk factors.
Colette
C
C
Laboratory of Human Nutrition and Atherogenesis, University Institute of Clinical Research, Montpellier, Cedex, France. colette@iurc1.iurc.montp.inserm.fr
Percheron
C
C
Pares-Herbute
N
N
Michel
F
F
Pham
T-C
TC
Brillant
L
L
Descomps
B
B
Monnier
L
L
D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D002478:Cells, Cultured; D008076:Cholesterol, HDL / Q000378:metabolism; D008078:Cholesterol, LDL / Q000378:metabolism; D004040:Dietary Carbohydrates / Q000378:metabolism*; D004041:Dietary Fats / Q000378:metabolism*; D005229:Fatty Acids, Monounsaturated / Q000378:metabolism*; D005231:Fatty Acids, Unsaturated / Q000378:metabolism; D005260:Female; D006801:Humans; D007328:Insulin / Q000097:blood; D008137:Longitudinal Studies; D008297:Male; D032389:Myocytes, Smooth Muscle / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D015431:Weight Loss / Q000502:physiology*
D001786:Blood Glucose; D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D004040:Dietary Carbohydrates; D004041:Dietary Fats; D005229:Fatty Acids, Monounsaturated; D005231:Fatty Acids, Unsaturated; D007328:Insulin