Background/Objectives: Diet composition is important for health, especially during critical periods such as pre-gestation (P), gestation (G), or lactation (S), due to its potential impact not only on the mother but on the offspring. The Mediterranean diet includes many healthy foods rich in fiber and/or polyphenols, such as whole grains, fruits, vegetables, beans, and nuts. The present preclinical study assesses the impact of a diet rich in fiber and polyphenols (HFP diet) during one of those three periods (P, G, or S, three weeks each) on the rat gene expression of the small intestine obtained at the end of the lactation period. Methods: This analysis was performed by the mRNA two step PCR amplification by random primers and poly-T, followed by library generation and HiSeq X-Ten Illumina sequencing (Seqplexing), and further confirmed by Real time PCR and ELISA. Results: The results showed a broad number of genes significantly modulated after the HFP diet compared to the reference diet, with a higher number of genes modulated when the supplementing period was closer to the analysis day (S > G > P). Notably, genes involved in immune signaling, intestinal absorption, and cell growth were among those more significantly affected by the HFP dietary intervention. The HFP diet influenced the expression of key genes such as ferritin, fatty acid synthase, apelin, and complement proteins, among others. There was a unique gene modified in all the intervention periods (Family with Sequence Similarity 117 Member A, Fam117A, which codifies a protein with unknown function), indicating that this molecule may participate critically in the effects induced by fiber and polyphenols during these periods. Conclusions: Overall, in rats, the influence of diet for a three-week period around birth is able to modulate the intestinal gene expression, and consequently, maternal health, which can eventually have an indirect impact on the offspring.

Maternal diet during lactation, pregnancy or even before can influence the health of the baby. The Mediterranean diet is the one with the highest level of evidence due to its richness in fiber and polyphenols, among other bioactive components. This study investigated the impact of a diet rich in fiber and polyphenols (HFP diet) supplemented during pregestation, gestation, and lactation at the intestinal level in both dams and their offspring. This diet had an intestinal impact in both pregnant rats and their offspring in terms of intestinal growth. Further research is required to elucidate the underlying mechanisms involved.

The Mediterranean diet (MD) is very rich in bioactive and immunomodulatory components. Some of these have demonstrated their protective activity in inflammation. The objective of this study was to evaluate the impact of a diet rich in fiber and polyphenols on an inflammatory process. The intervention was performed in two groups of 7-week-old rats, one receiving an experimental MD-like diet and another fed a reference diet (REF). At the end of the study, local inflammation was induced by injecting the rat’s paw with carrageenan. A lower paw volume was observed in = rats from the MD-like diet group.

Background/Objectives: Dietary fiber and polyphenols are recognized modulators of intestinal and immune homeostasis; however, evidence regarding their combined impact under physiological conditions remains limited. This study aimed to evaluate whether a diet enriched with fermentable fiber and polyphenols modulates mucosal and systemic immune biomarkers, as well as microbiota composition and function in healthy adult female rats. Methods: Wistar rats were fed either a reference diet (REF group) or a fiber- and polyphenol-enriched diet (FP group) for nine weeks. At the end of the intervention, plasma lipid profile, systemic and mucosal immune status (assessed by immunoglobulin (Ig) content in several compartments), cecal microbiota composition (determined by 16S rRNA sequencing), cecal short-chain fatty acids (SCFAs) and cecal Ig-coated bacteria, among other variables, were quantified. Results: The FP group exhibited a higher IgG concentration in plasma and elevated IgG2c levels in mucosal compartments compared with REF animals. The FP diet did not alter either intestinal morphology or hematologic and lipid variables; however, FP rats exhibited increased fecal moisture and reduced fecal pH. With regard to cecal microbiota, the FP group displayed higher microbial evenness, distinct β-diversity clustering, and shifts in the abundance of multiple genera. In addition, elevated cecal SCFA concentrations, particularly for acetate and propionate, were found in the FP group. Conclusions: Long-term intake of fermentable fiber and polyphenols promotes microbial fermentation and enhances humoral immunity without inducing structural or systemic physiological alterations. These findings support the role of plant-based foods in promoting immune and gut microbiota homeostasis under healthy conditions.