High Trans-Fat but not Saturated Fat Beverage Causes an Acute Reduction in Vascular Endothelial Function and Insulin Sensitivity in Humans

A diet high in trans-fatty acids (TFA) is associated with increased cardiovascular disease risk, mediated in part from dyslipidemia, endothelial dysfunction and insulin resistance. A high-fat meal causes a transient (3-4 hrs postprandial) reduction in endothelial function and insulin sensitivity, but studies are often confounded by meals high in carbohydrate, saturated fatty acids (SFAs) and/or TFAs. We hypothesized that a beverage high in TFA (but low in carbohydrate, SFA) would cause a larger acute reduction in endothelial function (brachial artery flow-mediated dilation, FMD) and insulin sensitivity compared with SFA (but low in carbohydrate, TFA). Healthy non-obese adults (n=11; 9M/2F; age=47±3 yrs) ingested a warm beverage (520kcal, 56g total fat, 5g carbohydrate), high in either TFA (42%TFA, 23%SFA; partially hydrogenated soybean oil), SFA (88%SFA, 0.2%TFA; coconut oil) or placebo (2g total fat, 5g carbohydrate) in a randomized, cross-over study. TFA (0.19±0.02 to 0.06±0.03mm, P<0.01), but not SFA (...