Effects of Low-Fat and High-Fat Meals, with and without Dietary Fiber, on Postprandial Endothelial Function, Triglyceridemia, and Glycemia in Adolescents

Abstract

The consumption of fiber-rich foods may negate the deleterious effects of high-fat meals on postprandial triglyceridemia and endothelial function. Despite supportive data in adults, little is known about the effects of high-fat and high-fiber foods on cardiovascular health parameters in pediatric populations. In this crossover trial, male and female adolescents (n = 10; 14.1 + 2.6 years; range 10-17 years) consumed (1) low-fat, low-fiber, (2) low-fat, high-fiber, (3) high-fat, low-fiber, and (4) high-fat, high-fiber breakfast meals in randomized order, each following an overnight fast. Baseline and 4 h post-meal blood was obtained for determination of glucose, insulin and triglyceride concentrations. Endothelial function was assessed via brachial artery flow-mediated dilation (FMD). Postprandial FMD was not significantly changed after any meal. However, regression analyses revealed a significant inverse relationship between the change in 4 h triglyceride concentration and change in 4 h FMD for the high-fat, low-fiber meal (β = -0.087; 95% CI = -0.138 to -0.037; p = 0.001) that was no longer significant in the high-fat, high-fiber meal (β = -0.044; 95% CI = -0.117 to 0.029; p = 0.227). Interpretation of these analyses must be qualified by acknowledging that between-meal comparison revealed that the two regression lines were not statistically different (p = 0.226). Addition of high-fiber cereal to the high-fat meal also reduced 4 h postprandial triglyceride increases by ~50% (p = 0.056). A high-fiber breakfast cereal did not attenuate postprandial glucose and insulin responses after consumption of a low-fat meal. While further work is needed to confirm these results in larger cohorts, our findings indicate the potential importance of cereal fiber in blunting the inverse relationship between postprandial hypertriglyceridemia and FMD after consumption of a high-fat meal in adolescents.

Keywords: cardiovascular disease; flow-mediated dilation; glycemia; insoluble fiber; insulin; pediatric; vascular; youth.

Conflict of interest statement

C.M.W. and G.A.G. serve as members of a scientific advisory board for Ardent Mills, L.L.C. G.A.G. serves as a member of the scientific advisory boards for the Wheat Foods Council and the Grain Foods Foundation.

Figures

Figure 1

Blood glucose concentrations over time in response to the four meals. Dashed lines represent individual subject responses. Solid line represents mean response for all subjects. See text and Table 3 for statistical comparisons.

Figure 2

Glycemic response as area under curve (AUC) over 4 h in response to the four meals. Boxes for each meal represent the interquartile range. Minimum and maximum values are indicated at the tips of each vertical line. The median for each meal is depicted by the horizontal line within each box. See Table 4 for statistical comparisons between meals.

Figure 3

Plasma insulin concentrations over time in response to four meals. Dashed lines represent individual subject responses. Solid line represents mean response for all subjects. See text and Table 5 for statistical comparisons between meals.

Figure 4

Plasma insulin as area under curve (AUC) over 4 h, in response to the four meals. Boxes for each meal represent the interquartile range. Minimum and maximum values are indicated at the tips of each vertical line. The median for each meal is depicted by the horizontal line within each box. See Table 6 for statistical comparisons between meals.

Figure 5

Plasma triglyceride responses to the four meals. Dashed lines represent individual subject responses. Solid line represents mean response for all subjects.

Figure 6

Change in plasma triglycerides over 4 h in response to the four meals. Minimum and maximum values are indicated at the tips of each vertical line. The median for each meal is depicted by the horizontal line within each box. See Table 7 for statistical comparisons.

Figure 7

Endothelial function, as measured by flow-mediated dilation (FMD), following the four meals. Dashed lines represent responses for each individual. Solid line represents the mean response (±SD). FMD was not different across time points for all meals.

Figure 8

Attenuating effects of including a high-fiber cereal with a high-fat, low-fiber breakfast meal on the association between the change in 4 h plasma triglyceride concentration and change in 4 h FMD. For high-fat, low-fiber: β = −0.087 (95% CI = −0.138 to −0.037; p = 0.001). For high-fat, high-fiber: β = −0.044 (95% CI = −0.117 to 0.029; p = 0.227). Direct comparison of the two regression lines indicated that the slopes were not different from one another (p = 0.226).