Afternoon distraction: a high-saturated-fat meal and endotoxemia impact postmeal attention in a randomized crossover trial

Abstract

Background: Saturated-fat intake and endotoxemia can impair cognition. However, their acute impact on cognitive performance is unknown.

Objective: This study assessed the impact of 2 high-fat meals and endotoxemia on attention.

Methods: In this double-blind, randomized crossover trial, 51 women (n = 32 breast cancer survivors, n = 19 noncancer controls; mean ± SD age: 53 ± 8 y) completed the Continuous Performance Test (CPT) and had their blood drawn to assess endotoxemia markers LPS binding protein (LBP), soluble CD14 (sCD14), and the LBP to sCD14 ratio 1 h prior to eating either a high-saturated-fat meal or a high-oleic-sunflower-oil meal. Women again completed the CPT 5 h postmeal. At 1 to 4 wk later, women completed the same protocol but consumed the other meal.

Results: In adjusted models, women had more difficulty distinguishing target stimuli from distractors after consuming the high-saturated-fat meal than they did after the oleic-sunflower-oil meal (B = 4.44, SE = 1.88, P = 0.02). Women with higher baseline LBP had less consistent response times (B = 0.002, SE = 0.0008, P = 0.04). Those with higher LBP and LBP:sCD14 were less able to sustain their attention throughout the entire CPT, as reflected by their progressively slower (B = 0.002, SE = 0.0006, P = 0.003; and B = 2.43, SE = 0.090, P = 0.008, respectively) and more erratic (B = 0.003, SE = 0.0008, P < 0.0001; and B = 3.29, SE = 1.17, P = 0.006, respectively) response times. Additionally, women with higher baseline LBP or sCD14 were less able to maintain or increase response speeds at higher interstimulus intervals (B = 0.002, SE = 0.0006, P = 0.02; and B = 0.006, SE = 0.003, P = 0.03, respectively), indicating greater difficulty adapting to changing task demands. Significant meal type by LBP and LBP:sCD14 interactions emerged (P < 0.05), such that high LBP and LBP:sCD14 erased between-meal cognitive differences, uniformly impairing performance.

Conclusions: These results suggest that higher LBP, sCD14, and LBP:sCD14 and saturated-fat intake individually and jointly influence attention. Endotoxemia may override the relative cognitive benefit of healthier oil choices.This trial is registered at clinicaltrials.gov as NCT04247763.

Keywords: attention; endotoxemia; lipopolysaccharide binding protein; sCD14; saturated fat.

Copyright © The Author(s) on behalf of the American Society for Nutrition 2020.

Figures

FIGURE 1

Flow of participants through the randomized crossover trial.

FIGURE 2

As indicated by their higher scores, women were less able to distinguish targets from nontargets during the postmeal CPT after the high-saturated-fat meal than after the high-monounsaturated-fat meal, adjusting for their premeal performance (hierarchical linear model; P = 0.02, n = 51). CPT, Continuous Performance Test.

FIGURE 3

(A–H) Women with elevated endotoxemia, as indexed by LBP, sCD14, and LBP:sCD14, had poorer attention across 4 CPT testing occasions (hierarchical linear models; P < 0.05, n = 51). The outcome of panels C, D, and E is the standard error of response times, a common metric of response time variability that indexes attention. Only significant results are depicted. Slope estimates are included in figure. CPT, Continuous Performance Test; LBP, LPS binding protein; sCD14, soluble CD14.

FIGURE 4

Experimental meal type interacted with endotoxemia markers to predict postmeal CPT detectability (hierarchical linear models; P < 0.05, n = 51). The saturated-fat meal only had an attentional impact in the context of minimal endotoxemia. Elevated endotoxemia erased meal-related differences, as women with higher endotoxemia performed equally poorly regardless of meal type. The shaded area represents 95% CIs. Only significant results are depicted. Slope estimates (SE) for each panel are as follows: (A) sunflower oil: 0.0020 (0.00083); saturated fat: −0.0011 (0.00082); (B) sunflower oil: 2.0 (1.1); saturated fat: −2.1 (1.1); (C) sunflower oil: 0.59 (0.70); saturated fat: −1.22 (0.74). CPT, Continuous Performance Test; LBP, LPS binding protein; Pctl, percentile; sCD14, soluble CD14.