Maternal Extra Virgin Olive Oil Supplementation Enhances Offspring Immune Function: A Preclinical Study

Abstract

Maternal diet influences offspring development, immune function, and intestinal health. This study investigates the effects of maternal supplementation with a key component of the Mediterranean Diet, extra virgin olive oil (EVOO), on the immune health of offspring at the end of lactation. Lewis rat dams received either refined olive oil (ROO), EVOO, or water (REF) during gestation and lactation. Plasma immunoglobulin G2c (IgG2c) concentration was elevated in pups born to EVOO-supplemented mothers, indicating enhanced immune development. Histological analysis of the small intestine revealed more goblet cells in the EVOO group, indicating a potential positive effect on the intestinal barrier function. In vitro assays showed that EVOO metabolites did not display cytotoxicity and had improved barrier integrity under a stress stimulus. These findings suggest that maternal EVOO supplementation may have beneficial effects on immune and intestinal development and health in offspring.

Keywords: extra virgin olive oil; immune system; maternal supplementation; offspring.

Figure 1

Plasma adiponectin and leptin levels at the end of the sucking period. Adiponectin (A) and leptin (B) levels and their ratio (C) in REF, ROO, and EVOO groups. Spearman correlations between pups’ plasma and their weight and between pups’ plasma and both dams’ plasma and mammary gland (D). Results are expressed as mean ± standard error of the mean (SEM) (n = 12–15 pups/group). Statistical differences: * p < 0.05 vs. REF group. Spearman’s correlation coefficient is represented in the heat map following the color in the legend. Bold frames represent correlations with statistical significance (p < 0.05).

Figure 2

Effect of maternal supplementation on the Ig profile in pups’ plasma. Plasma IgA (A), IgM (B), and IgG (C) from REF, ROO, and EVOO groups. IgG subtypes (D) and their relative proportion (E). Analysis of the Th1/Th2 ratio at the end of suckling (F). Analysis of non-parametric multidimensional scaling (NMDS) for the Ig profiles based on the Bray–Curtis distance (G). Spearman correlations between dams’ plasma and pups’ plasma (H) and between breast milk and pups’ plasma (I). Results (A–D) are expressed as mean ± standard error of the mean (SEM) (n = 12–15). Statistical differences: * p < 0.05 vs. REF # p < 0.05 vs. ROO. The Spearman correlation coefficient is represented in the heat map following the color in the legend. Bold frames represent correlations with statistical significance (p < 0.05).

Figure 3

Gene expression of Toll-like receptors (TLRs) (A), maturation biomarkers (B), and IgA (C) at the end of the suckling period in the small intestine. Results are expressed with respect to the REF group, which corresponded to 100% of transcription (dashed line) (n = 9 pups/group). IgA concentration (D) in small intestine and Ig-coated bacteria (E) in cecal content. Results are expressed as mean ± standard error of the mean (SEM) (n = 18–36). Statistical differences: * p < 0.05 vs. REF group; # p < 0.05 vs. ROO group.

Figure 4

Effect of ROO and EVOO on the small intestine of the three groups of pups at the end of the suckling period. Gene expression of intestinal mucins (A) and tight junctions (B), calculated with respect to REF, which corresponded to 100% transcription (dashed line) (n = 9 pups/group). Height (C), width (D), area of the villi (E), number of Goblet cells/villi (F), crypt depth (G), and ratio of villi height–crypt depth (H) of the three groups. Results in (C–H) are expressed as mean ± standard error of the mean (SEM) (n = 18–36 pups/group). Statistical differences: * p < 0.05 vs. REF group; # p < 0.05 vs. ROO group. Representative images of histological sections of the medial intestine with periodic acid–Schiff (PAS) (I) and hematoxylin–eosin staining (J). Goblet cells with densely stained granules can be observed along the villi (I). Scale bar = 200 μm for 10×.

Figure 5

LDH activity as an indicator of cell membrane integrity (A). Measurement of TEER values in Caco-2 cells at different time points (1 h, 2 h, 3 h) during incubation with hippuric acid (HPP), homovanillic acid (HV), and hydroxyphenyl acetic acid (HFA) (B). Results are expressed as a percentage, with the value at time 0 set to 100%. Statistical differences: * p < 0.05 vs. C+. # p < 0.05 vs. C-. C-, control conditions (medium); C+, positive control (H₂O₂, 3 mM).