Postprandial Fatty Acid Profile, but Not Cardiometabolic Risk Markers, Is Modulated by Dairy Fat Manipulation in Adults with Moderate Cardiovascular Disease Risk: The Randomized Controlled REplacement of SaturatEd fat in dairy on Total cholesterol (RESET) Study

Abstract

Background: Chronic consumption of dairy products with an SFA-reduced, MUFA-enriched content was shown to impact favorably on brachial artery flow-mediated dilatation (FMD). However, their acute effect on postprandial cardiometabolic risk biomarkers requires investigation.

Objective: The effects of sequential high-fat mixed meals rich in fatty acid (FA)-modified or conventional (control) dairy products on postprandial FMD (primary outcome) and systemic cardiometabolic biomarkers in adults with moderate cardiovascular risk (≥50% above the population mean) were compared.

Methods: In a randomized crossover trial, 52 participants [mean ± SEM age: 53 ± 2 y; BMI (kg/m2) 25.9 ± 0.5] consumed a high-dairy-fat breakfast (0 min; ∼50 g total fat: modified: 25 g SFAs, 20 g MUFAs; control: 32 g SFAs, 12 g MUFAs) and lunch (330 min; ∼30 g total fat; modified: 15 g SFAs, 12 g MUFAs; control: 19 g SFAs, 7 g MUFAs). Blood samples were obtained before and until 480 min after breakfast, with FMD assessed at 0, 180, 300, and 420 min. Data were analyzed by linear mixed models.

Results: Postprandial changes in cardiometabolic biomarkers were comparable between the different dairy meals, with the exception of a tendency for a 4% higher AUC for the %FMD response following the modified-dairy-fat meals (P = 0.075). Plasma total lipid FA analysis revealed that incremental AUC responses were 53% lower for total SFAs, 214% and 258% higher for total cis-MUFAs (predominantly cis-9 18:1), and trans-18:1, respectively, following the modified relative to the control dairy meals (all P < 0.0001).

Conclusions: In adults at moderate cardiovascular risk, acute consumption of sequential high-fat meals containing FA-modified dairy products had little impact on postprandial endothelial function or systemic cardiometabolic biomarkers, but a differential effect on the plasma total lipid FA profile, relative to conventional dairy fat meals.This trial was registered at clinicaltrials.gov as NCT02089035.

Keywords: endothelial function; monounsaturated fatty acids; postprandial lipemia; saturated fatty acids; sequential test meal protocol.

FIGURE 1

Flow of participants through the study. %FMD, percentage of flow-mediated dilatation response.

FIGURE 2

Time-course profiles of postprandial plasma total lipid FAs in response to sequential high-fat mixed-meal challenges (breakfast at 0 min and lunch at 330 min) rich in FA-modified or conventional dairy products (control) in adults at moderate cardiovascular risk for total SFAs (A), 14:0 (B), 15:0 (C), 16:0 (D), and 18:0 (E). Values are untransformed and unadjusted means ± SEMs, n = 47–48. The dotted lines represent the timing of the second meal (330 min). Linear mixed-model analysis was used to explore the effects of treatment and time, with an adjustment made in all cases for fixed effects of period, time, treatment, gender, age, and BMI. Participant was included as a random effect. P ≤ 0.01 was deemed significant to acknowledge multiplicity. FA, fatty acid.

FIGURE 3

Time-course profiles of postprandial plasma total lipid FAs in response to sequential high-fat mixed-meal challenges (breakfast at 0 min and lunch at 330 min) rich in FA-modified or conventional dairy products (control) in adults at moderate cardiovascular risk for cis-MUFAs (A), cis-9 18:1 (B), trans-MUFAs (C), trans-9 18:1 (D), trans-10 18:1 (E), and trans-11 18:1 (F). Values are untransformed and unadjusted means ± SEMs, n = 49. The dotted lines represent the timing of the second meal (330 min). Linear mixed-model analysis was used to explore the effects of treatment and time, with an adjustment made in all cases for fixed effects of period, time, treatment, gender, age, and BMI. Participant was included as a random effect. P ≤ 0.01 was deemed significant to acknowledge multiplicity. FA, fatty acid.