Differential Effects of Two Isoenergetic Meals Rich in Saturated or Monounsaturated Fat on Endothelial Function in Subjects With Type 2 Diabetes

Abstract

OBJECTIVE -To examine the acute effects of consumption of monounsaturated (MUFAs) and saturated fatty acids (SAFAs) on endothelial function in subjects with type 2 diabetes.RESEARCH DESIGN AND METHODS -A total of 33 participants were examined after consumption of two different isocaloric meals: one rich in MUFA and one rich in SAFA, in the form of extra-virgin olive oil and butter, respectively. Endothelial function was assessed by determination of flow-mediated dilatation (FMD).RESULTS -FMD did not change significantly after the MUFA-rich meal but declined after the SAFA-rich meal. The FMD during the experiment, expressed as incremental area under the curve, increased after the MUFA-rich meal by 5.2 Ϯ 2.5% and decreased after the SAFA-rich meal by 16.7 Ϯ 6.0% (⌬ ϭ Ϫ11.5 Ϯ 6.4%; P ϭ 0.008).CONCLUSIONS -Consumption of an SAFA-rich meal is harmful for the endothelium, while a MUFA-rich meal does not impair endothelial function in subjects with type 2 diabetes.

Metabolic Effects of Monounsaturated Fatty Acid–Enriched Diets Compared With Carbohydrate or Polyunsaturated Fatty Acid–Enriched Diets in Patients With Type 2 Diabetes: A Systematic Review and Meta-analysis of Randomized Controlled Trials

“…Our study only included studies that examined individuals with T2D or noninsulin-dependent diabetes; hence, it is unclear whether these metabolic benefits can be extended to individuals with impaired glucose tolerance or type 1 diabetes, although some studies suggest a similar benefit (3,64). Furthermore, we examined only metabolic risk factors that were consistently measured and reported in each study, but the benefits of a high-MUFA diet may also be mediated through effects on inflammation (65), endothelial function (66), and body fat distribution (67), which all warrant further research. Most of the trials in our analysis were conducted among Western populations, which may limit the generalizability of our findings to other populations.…”

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

“…In contrast, some studies have shown impairment in FMD with high MUFA meals [24e26,32] while others have shown no effect [30,32e34]. High SFA meals mainly from cream [9,10], butter [30], palm oil [28], palmstearin [35] or McDonalds take-away [27,31] have been shown to impair postprandial FMD while others have failed to show any effect with SFA from tallow fat [33] or palm kernel fat [36]. The postprandial effects of palmolein on vascular function have not yet been investigated.…”

“…The inconsistent findings previously reported could be in part explained by disparities in other meal components. Addition of anti-oxidant vitamins or food sources rich in polyphenols [23,25,30,37], protein (particularly those rich in L-arginine) [9,10,25] or omega-3 fatty acids [35] have been shown to counteract postprandial FMD suppression associated with ingestion of high-fat meals. The addition of 2.5 g L-arginine to a cream-based fat load prevented any deterioration in FMD that was shown with the high fat load alone [10].…”

SFAs do not impair endothelial function and arterial stiffness

“…In this context, it is relevant to consider the beneficial effects on FMD that have been reported in subjects given virgin olive oil (12, 14, 15, 24), which are now being attributed to its polyphenol content rather than its HM content. We were careful to standardize the vitamin E content of fats used in our study and used the same ratio of linoleic:linolenic acid in fat spreads.…”

“…Keogh et al (11) reported that FMD was impaired after a high-SFA (HS) diet compared with high-MUFA (HM), high-PUFA, or high-carbohydrate (HC) diets. Several studies have also reported that adherence to a Mediterranean style diet is associated with improvements in endothelial function (12–14), which have often been attributed to the consumption of virgin olive oil, which is rich in MUFAs. However, it has also been suggested that the effect on endothelial function is mediated by antioxidants in virgin olive oil (15).…”