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.

Palmolein and olive oil consumed within a high protein test meal have similar effects on postprandial endothelial function in overweight and obese men: A randomized controlled trial

“…The intraobserver coefficient of variation for FMD in this operator's hands was 15% based on repeated scans performed on 10 healthy individuals on two separate occasions under similar circumstances prior to study commencement. This CV is similar to that reported in other laboratories in similar populations [17].…”

Saturated Fats Versus Polyunsaturated Fats Versus Carbohydrates for Cardiovascular Disease Prevention and Treatment

“…There is inconsistent evidence for effects of SFAs on vascular function as assessed by flow-mediated dilation (88, 139, 151). A summary of epidemiological, intervention, and meal test studies concluded that low-fat diets may be beneficial relative to diets high in SFAs or when MUFAs replace SFAs (174).…”

Nutrition and other lifestyle influences on arterial aging

“…Direct evidence for this in humans is limited and less consistent. Most reports do indicate that diets high in saturated fat reduce endothelial function (although primarily in middle-aged/older adults with pre-existing risk factors) (Fuentes et al, 2008; Keogh et al, 2005), but the influence of these diets on arterial stiffness is less clear; some have found that high fat diet increases stiffness, while others have observed no effects (Hall, 2009; Sanders et al, 2013). Thus, there is a clear need for future trials aimed at establishing the effects of suboptimal (e.g., Western) diet on arterial functions in humans with aging—especially because this is the diet consumed by most middle-aged/older adults in developed (and developing) countries.…”