Dietary Intake of Polyphenols Enhances Executive/Attentional Functioning and Memory with an Improvement of the Milk Lipid Profile of Postpartum Women from Argentina

Abstract

Puerperium may lead to memory and executive/attentional complaints that interfere with women's daily life. This might be prevented by dietary compounds, such as neuroprotective polyphenols. Their bioactivity depends on their effects on lipid metabolism in different tissues, such as the brain, fat, and breast. Thus, a polyphenol-related cognitive improvement may be associated with changes of lipids in human milk, which are key for infant neurodevelopment. A cross-sectional study was conducted on 75 postpartum women from Córdoba (Argentina), involving several neuropsychological tests. Diet was registered to identify polyphenol intake and food pattern adherence, with sociodemographic and other psychological variables (insomnia, stress, subjective cognitive complaints) being also studied. Triacylglycerols, cholesterol, and their oxidative forms were analyzed as milk biomarkers. Multivariate statistical methods were applied. Results confirmed that women who consumed polyphenols presented better executive/attentional performance (i.e., higher correct responses, conceptual level responses, complete categories, verbal fluency; lower attentional interferences, and perseverative errors) and word retention with lower interference. Polyphenols were positively associated with milk lipids, which were higher in women with better cognition. Furthermore, they had lower oxidized triacylglycerols. In conclusion, polyphenolic intake during postpartum may improve executive/attentional functioning, memory, and milk lipid profile.

Keywords: Rey Auditory Verbal Learning Test; Stroop Test; Wisconsin Card Sorting Test; breast feeding; diet; language tests; lipids; mental health; oxidative stress; polyphenols.

Figure 1

Directed acyclic graph of the relationship among polyphenol intake, cognition, and human milk lipids in postpartum Argentinian women. Green squares indicate the independent (dietary polyphenol intake and cognition) and dependent variables (human milk lipids); red squares indicate minimal sufficient adjustment variables; the bold arrow indicates the relationship between the independent and dependent variables; thin arrows indicate other causal relationships.

Figure 2

Daily dietary polyphenolic intake in postpartum women from Córdoba, Argentina (n = 75), with data being expressed as mean and standard errors.

Figure 3

HJ-Biplot representation (axis 1–2) for clusters of polyphenols consumed above 20 mg/d (a) and between 5 and 20 mg/d (b) by Argentinian postpartum women.

Figure 4

Wisconsin Card Sorting Test (WCST) scores according to polyphenolic intake clusters (>20 mg/d). ANCOVA models were carried out with Fisher’s post hoc contrast and adjusted by educational level, postpartum days, parity, dietary indices (macronutritional, phytochemical, and energetic), and insomnia. C1: n = 34; C2: n = 24; C3: n = 17. D = Cohen’s d for effect size; * p < 0.05.

Figure 5

Postpartum women’s performance in the Rey Auditory Verbal Learning Test (RAVLT), Stroop Color and Word Test (SCWT), and Verbal Fluency Task (VFT) according to polyphenolic intake clusters (>20 mg/d). ANCOVA models were adjusted by educational level, postpartum days, parity, dietary indices (macronutritional, phytochemical and energetic), and insomnia, with a Fisher’s post hoc contrast. C1: n = 34; C2: n = 24; C3: n = 17. d = Cohen’s d for effect size; * p < 0.05.

Figure 6

Postpartum women’s performance in the Wisconsin Card Sorting Test (WCST), Rey Auditory Verbal Learning Test (RAVLT), and Stroop Color and Word Test (SCWT) according to polyphenolic intake clusters (5 to 20 mg/d). ANCOVA models were adjusted by educational level, postpartum days, parity, dietary indices (macronutritional, phytochemical, and energetic), and insomnia, with a Fisher’s post hoc contrast. C1: n = 33; C2: n = 29; C3: n = 13. d = Cohen’s d for effect size; * p < 0.05.

Figure 7

HJ-Biplot representation for clusters in the main plane (axis 1–2) for the executive/attentional functioning (a) and memory (b) in Argentinian postpartum women. SCWT = Stroop color and word test; I = Interference; C = Color; W = Word; W/C = Word-Color; WCST = Wisconsin card sorting test; TC1 °C = Trials to complete first category; %NPE = Percentage of non-perseverative errors; %TE = Percentage of total errors; GS = Global score; TA = Trials administered; FMS = Failure to maintain set; %PR = Percentage of perseverative responses; %PE = Percentage of perseverative errors; CR = Correct responses; CLR = Conceptual level responses; CA = Categories achieved; %CLR = Percentage of conceptual level responses; LL = Learning to learn; VFT:ELA = Verbal fluency task, excluded letter A; RHR = recency hit rate; MHR = middle hit rate; TA1 = Trial A1; IT = interference trial (B); PIT = post-interference trial (A6); PHR = primacy hit rate; R = recognition; DR = delayed recall; MEI = memory efficiency index; F = forgetting; %F = percentage of forgetting; L = Learning; CTL = Corrected total learning; ΣA1–5 = sum trials A1 to A5; IR, immediate recall; VF-P, verbal fluency letter P; VF-F, verbal fluency letter F; VF-Animals, verbal fluency Animals; PrI = proactive interference; ReI = retroactive interference; TA5 = trial A5; E = evocation; Ret = retention; IE = Intrusion errors; ER = errors of repetitions; FS = forgetting speed; VFT = verbal fluency task; LF = letter F; LP = letter P; S = semantic.