No Difference in Lipemic Response or Endothelial Function Following Interesterified and Non-Interesterified Functionally Equivalent Fats: A Randomized Controlled Trial

Interesterified (IE) fats are now used as hard fats to replace harmful trans fats, however the cardiometabolic health impact of the most commonly consumed IE fat blends are unknown. The InterCardio study (NCT03438084) investigated the effect of the most commonly consumed IE spread versus functionally equivalent hard fats and a control oil, on postprandial lipemia (PPL) and acutely changing markers of endothelial function. A four-armed, double blind, randomized controlled trial in healthy males and females (n = 50) aged 35–75 years compared sequential test meals (0 h; 897 kcal, 50 g fat, 16 g protein, 88 g carbohydrate, 5 h; 550 kcal, 30 g fat, 15 g protein, 39 g carbohydrate) on postprandial plasma triacylglycerol (TG) concentrations, endothelial function (flow mediated dilation (FMD)), plasma nitrite concentrations and NADPH oxidase activity. Test fats were: a commercially available IE spread, a functionally equivalent non-IE spread, spreadable butter (SB), and a high-MUFA oil (rapeseed oil) as control. Melt curve data for the spreadable fats showed similar solid fat content at 37°C (IE; 0.3%, non-IE; 0.4%, SB; 0%). Blood was collected at fasting and regular intervals up to 8 hrs, and FMD was measured at fasting, 4.5 hrs and 7.5 hrs. All 4 test fats increased TG levels postprandially, reaching peak concentrations at 6 hrs. There was no significant treatment or treatment x time effects on plasma TAG concentrations (P = 0.684), nor incremental areas under the curves up to 4 and 8 hrs; mean iAUC0–8 h (95% CI) were 5.4 mmol/L.h (4.3, 6.4) for IE spread, 5.7 mmol/L.h (4.3, 6.8) for non-IE spread, 5.5 mmol/L.h (4.0, 7.0) for SB and 5.9 mmol/L.h (4.3,6.8) for rapeseed oil. There were no significant treatment effects on endothelial function, while nitrite concentrations and NADPH oxidase activity reduced postprandially. Mean NAPDH oxidase activity following IE spread, non-IE spread, SB and rapeseed oil at 6 h were 322, 333, 270, and 268 respectively. In the first study to investigate the acute effects of commercially relevant IE and non-IE spreads and SB, we report no adverse effect of IE fats on acutely changing cardiometabolic risk factors relative to a high-MUFA reference oil. The similar effects on endothelial function and postprandial lipemia is likely to be due to their similar solid fat content at body temperature. BBSRC.