Flow-mediated dilatation is impaired by a high-saturated fat diet but not by a high-carbohydrate diet.
OBJECTIVE
It is unknown whether a low-fat diet, which may elevate triglycerides and lower high-density lipoprotein (HDL) cholesterol, harms the endothelium. Our aim was to determine whether a low-fat, high-carbohydrate (CARB) diet impaired endothelial vasodilation compared with high saturated fat (SFA), monounsaturated fat (MUFA), or polyunsaturated fat (PUFA) diets.


RESULTS
Forty healthy subjects were randomly crossed over to 4, 3-week isocaloric diets high in PUFA, MUFA, or SFA, containing at least 25 g of the relevant fat or a low-fat, CARB, high-glycemic load diet. Flow-mediated dilatation (FMD), fasting blood lipids, high sensitivity C-reactive protein, plasma intercellular, and vascular adhesion molecules plasma E- and P-selectin were measured after each intervention. SFA impaired FMD compared with all other diets (5.41+/-2.45% versus 10.80+/-3.69%; P=0.01). FMD did not change on CARB relative to MUFA or PUFA, despite 23% to 39% rises in triglyceride and 10% to 15% falls in HDL cholesterol. P-selectin was highest after SFA (121+/-52.7 ng/mL) versus MUFA (98+/-44.5 ng/mL; P=0.001) and PUFA (96+/-36.4 ng/mL; P=0.001).


CONCLUSIONS
High SFA caused deterioration in FMD compared with high PUFA, MUFA, or CARB diets. Inflammatory responses may also be increased on this diet.
Keogh
Jennifer B
JB
CSIRO Health Sciences and Nutrition, Adelaide BC, South Australia.
Grieger
Jessica A
JA
Noakes
Manny
M
Clifton
Peter M
PM
D000328:Adult; D000368:Aged; D001055:Apolipoproteins B / Q000097:blood; D050197:Atherosclerosis / Q000178:diet therapy* / Q000276:immunology / Q000503:physiopathology*; D015415:Biomarkers; D001783:Blood Flow Velocity; D001835:Body Weight; D001916:Brachial Artery / Q000502:physiology; D018592:Cross-Over Studies; D004040:Dietary Carbohydrates / Q000008:administration & dosage*; D004041:Dietary Fats / Q000008:administration & dosage*; D004435:Eating; D005227:Fatty Acids / Q000008:administration & dosage*; D005229:Fatty Acids, Monounsaturated / Q000008:administration & dosage; D005231:Fatty Acids, Unsaturated / Q000008:administration & dosage; D005260:Female; D006801:Humans; D007328:Insulin / Q000097:blood; D008297:Male; D008875:Middle Aged; D015596:Nutrition Assessment; D010349:Patient Compliance; D011673:Pulsatile Flow; D014280:Triglycerides / Q000097:blood; D014664:Vasodilation
D001055:Apolipoproteins B; D015415:Biomarkers; D004040:Dietary Carbohydrates; D004041:Dietary Fats; D005227:Fatty Acids; D005229:Fatty Acids, Monounsaturated; D005231:Fatty Acids, Unsaturated; D007328:Insulin; D014280:Triglycerides