Dear Colleagues,

In recent years, there has been a growing scientific shift toward understanding diet not merely as a source of nutrients, but as a complex biological system interacting dynamically with human physiology. Traditional and region-specific diets, often shaped by environmental constraints and empirical knowledge, represent valuable models for investigating such interactions within contemporary biomedical frameworks.

This Topical Collection (TC) aims to explore the health-related biological dimensions of traditional dietary patterns through a strictly scientific lens. The focus is not on cultural, gastronomic, or heritage narratives -those have their place elsewhere- but on measurable, mechanistic, and translational aspects of nutrition. Emphasis is placed on the compositional, functional, and microbiological properties of foods, and their interactions with human biological systems.

A distinctive feature of this TC is the integration of oral health as a primary biological interface. The oral cavity constitutes the first point of contact between diet and the human organism, serving as a dynamic environment for microbial colonization, biochemical transformation, and immune signaling. Emerging evidence positions the oral ecosystem, particularly saliva and the oral microbiome, as a critical mediator of diet-health interactions and a promising source of early biomarkers for both oral and systemic conditions. Despite this, it remains underrepresented in nutrition research, a gap this collection explicitly seeks to address.

Submissions are invited that address, but are not limited to, the following areas:

• Nutritional composition and bioactive profiles of traditional and regional foods;
• Functional compounds and their mechanistic roles in health and disease;
• Fermentation processes and food-associated microbiota;
• Diet–microbiome interactions beyond the gut, including oral, salivary, and mucosal environments;
• Modulation of the oral microbiome and salivary biomarkers through diet;
• Oral–systemic health connections mediated by dietary factors;
• Functional foods within preventive and translational nutrition frameworks;
• Identification and validation of dietary biomarkers in oral biofluids.

Within this framework, traditional dietary systems from specific regions may be included as scientifically grounded case studies, provided that their investigation is based on analytical, microbiological, or clinical methodologies.

For example, Pontic Greek cuisine may be examined in terms of:

• Nutritional composition and functional properties;
• Fermented food products and their microbial ecology;
• Potential modulation of oral and systemic health pathways.

Importantly, such regional approaches are not treated as cultural narratives but as biological and translational models, comparable to other traditional dietary systems (e.g., Mediterranean, Nordic, or Asian dietary patterns) when investigated through strong scientific methodologies. Submissions that combine methodological rigor with interdisciplinary relevance are particularly encouraged.

Prof. Dr. Theodoros Varzakas
Dr. Maria Antoniadou
Collection Editors