SFAs do not impair endothelial function and arterial stiffness

Abstract

Background: It is uncertain whether saturated fatty acids (SFAs) impair endothelial function and contribute to arterial stiffening.

Objective: We tested the effects of replacing SFAs with monounsaturated fatty acids (MUFAs) or carbohydrates on endothelial function and arterial stiffness.

Design: With the use of a parallel-designed randomized controlled trial in 121 insulin-resistant men and women, we measured vascular function after 1 mo of consumption of a high-SFA (HS) diet and after 24 wk after random assignment to the HS diet or diets that contained <10% SFAs and were high in either MUFAs or carbohydrates. The primary outcome was a change in flow-mediated dilation (FMD), and secondary outcomes were changes in carotid to femoral pulse wave velocity (PWV) and plasma 8-isoprostane F2α-III concentrations.

Results: For 112 participants with data available for analysis on the specified outcomes, no significant differences were shown. FMD with the HS reference diet was 6.7 ± 2.2%, and changes (95% CIs) after 6 mo of intervention were +0.3 (-0.4, 1.1), -0.2 (-0.8, 0.5), and -0.1 (-0.6, 0.7) with HS, high-MUFA (HM), and high-carbohydrate (HC) diets, respectively. After consumption of the HS reference diet, the geometric mean (±SD) PWV was 7.67 ± 1.62 m/s, and mean percentages of changes (95% CIs) were -1.0 (-6.2, 4.3) with the HS diet, 2.7 (-1.4, 6.9) with the HM diet, and -1.0 (-5.5, 3.4) with the HC diet. With the HS reference diet, the geometric mean (±SD) plasma 8-isoprostane F2α-III concentration was 176 ± 85 pmol/L, and mean percentage of changes (95% CIs) were 1 (-12, 14) with the HS diet, 6 (-5, 16) with the HM diet, and 4 (-7, 16) with the HC diet.

Conclusion: The replacement of SFAs with MUFAs or carbohydrates in healthy subjects does not affect vascular function. This trial was registered at Current Controlled Trials (http://www.controlled-trials.com/ISRCTN) as ISRCTN 29111298.

FIGURE 1.

Consolidated Standards of Reporting Trials diagram showing flow of participants through the study. FMD was not measured in participants in the HM/LGI or HC/LGI groups. FMD, flow-mediated dilation; HC/HGI, high carbohydrate/high glycemic index; HC/LGI, high carbohydrate/low glycemic index; HM/HGI, high MUFA/high glycemic index; HM/LGI, high MUFA/low glycemic index; HS, high SFA; HS/HGI, high SFA/high glycemic index.