Metals: Balancing Act in Health and Disease

Dear Colleagues,

Essential metals play a fundamental role in human health, acting as cofactors and regulators in metabolic pathways, cellular growth, organ development, and immune function. Their biological effects depend on a delicate balance between adequate intake, bioavailability—which is strongly influenced by interactions among metals and with other dietary components—and excessive exposure. Variability in metal concentrations in dietary sources, including food and drinking water, as well as differences in nutritional practices and environmental exposures, can significantly affect metal status, leading to deficiency, adequacy, or toxicity. Both extremes may be associated with adverse health outcomes.

Regions affected by deficiencies in essential metals often overlap geographically with areas experiencing a growing burden of chronic non-communicable diseases, such as obesity and diabetes, and their related comorbidities. Understanding how metal homeostasis interacts with metabolic health is therefore critical for the development of prevention and therapeutic strategies.

While water filtration and purification systems effectively reduce exposure to potentially harmful metals, they may inadvertently decrease intake of essential elements. This dual impact highlights the need for careful evaluation of water treatment practices and their long-term implications for human nutrition and health, particularly in specific population subgroups and regions where drinking water contributes substantially to essential metal intake.

On the other hand, the increasing and often unsupervised use of metal-containing dietary supplements raises concerns regarding excessive metal intake, exposure to harmful metals due to inadequate quality control, and interactions with other dietary components. For example, high consumption of calcium supplements can interfere with the intestinal absorption and bioavailability of iron, zinc, and magnesium, potentially exacerbating deficiencies despite adequate dietary intake. These interactions are particularly relevant for vulnerable populations, including individuals with metabolic disorders, infants, older adults, and those following restricted or specialized diets.

We invite researchers to contribute original research articles, epidemiological and interventional studies, biomonitoring data, and comprehensive reviews addressing the complex balance of metals in health and disease. Contributions focusing on mechanistic and translational research are especially encouraged. Topics of interest include, but are not limited to, studies spanning exposure, internal dose, mechanisms, and clinical outcomes related to metal balance in health and disease, including:

1. Essential versus toxic metals, thresholds, nutritional status, nonlinear dose–response relationships, and metabolic regulation;
2. Essential and toxic metals in the food chain;
3. Sources of metal exposure (e.g., environmental contamination of the food chain, dietary contaminants);
4. Metallomics, metal speciation, and multi-element profiling, including the identification of novel biomarkers of exposure and effect, and the evaluation of their clinical relevance;
5. Lifelong, low-dose, mixed metal exposures, and the exposome, particularly in relation to cardiometabolic risk and life course health;
6. Metal homeostasis and metabolic diseases (including obesity, diabetes, and steatotic liver disease) or other chronic non-communicable conditions;
7. Interactions between metal exposure and the gut microbiome, endocrine signaling, immune and inflammatory pathways, and other mechanistic systems;
8. Metals in biological aging, including epigenetic alterations, aging biomarkers, and long-term health outcomes.

Dr. Maria João Martins
Dr. Agostinho Almeida
Dr. Helena Carmo
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 250 words) can be sent to the Editorial Office for assessment.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Nutrients is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2900 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

• essential and toxic metals
• metal–nutrient interactions
• metal sources and bioavailability
• metallomics
• non-communicable diseases
• gut microbiome
• inflammation
• oxidative stress
• biomarkers
• biological aging