Interactions of Nutrition and Infection: The Role of Micronutrient Deficiencies in the Immune Response to Pathogens and Implications for Child Health

Dietary magnesium intake affects the association between dietary vitamin A and depression: a cross-sectional study

Introduction

Depression represents a significant global health burden, ranking as one of the leading causes of disability worldwide, and nutrition plays a key role in mental health. Vitamin A, essential for immune and neurological function, has shown conflicting associations with depression. Magnesium, essential for neurotransmission and neuroprotection, is associated with a reduced risk of depression. Importantly, magnesium is required for the activation of enzymes involved in vitamin A metabolism, suggesting a potential interaction between these nutrients in depression. However, this interaction remains poorly understood. This study investigates how magnesium intake modifies the relationship between vitamin A and depression, with the aim of elucidating their combined effects and informing personalized dietary strategies for depression prevention.

Research design and methods

Data for this study were extracted from the National Health and Nutrition Examination Survey (NHANES) conducted between 2005 and 2016, involving a total of 60,936 participants. The final analysis included 25,277 adults aged ≥20 years (Female: 12,581, Male:12,696), excluding pregnant women, individuals under 20, and those with incomplete data. Depression was assessed using the Patient Health Questionnaire-9 (PHQ-9), supplemented by self-reporting questionnaires. Dietary intake was assessed via a recall interview at the mobile examination center (MEC). Dietary vitamin A intake, treated as a continuous variable, was categorized based on the median intake value. Stratified analyses were conducted based on sex and magnesium intake levels (Female: low: <310 mg/day; high: ≥310 mg/day; Male: low: <400 mg/day; high: ≥400 mg/day).

Results

Our cross-sectional study showed that in women with low magnesium intake, higher vitamin A intake was associated with a reduced risk of depression (OR: 0.83, 95% CI: 0.76-0.92, p < 0.001), whereas no significant association was observed in the high magnesium group. Men did not show such an interaction. There was also a significant interaction between vitamin A levels and magnesium intake in reducing the incidence of depression (p-value for interaction = 0.145).

Conclusion

Our study suggests that a sex-specific interaction between dietary magnesium and vitamin A in modulating depression risk. This interaction highlights the potential role of combined nutritional interventions in depression management. Further randomized controlled trials are warranted to confirm these findings.

Two-phase linear relationship of Vitamin D and Vitamin A among children aged 0-14 years: a cross-sectional study

Background

Vitamin D and Vitamin A are crucial for children's immune function, bone health, and cellular growth, but their interrelationship and the impact of various factors remain poorly understood.

Objective

To explore the relationship between Vitamin D and Vitamin A levels in children and identify any critical thresholds.

Methods

A cross-sectional study was conducted from 2018 to 2021 in Ningbo, Zhejiang, China. Participants were children aged 0 to 14 years attending community health service centers for routine health check-ups. Multivariate linear regression analysis was conducted to ascertain the association between serum Vitamin D and Vitamin A levels. A smooth curve fitting approach was employed to analyze the dose-response relationship between Vitamin D and Vitamin A.

Results

A total of 4,752 participants were included. The study revealed significant variations in baseline Vitamin D and Vitamin A levels across different deficiency categories. Mean Vitamin D levels were lowest in the severe deficiency group (4.9 ng/mL) and highest in the normal group (34.8 ± 9.8 ng/mL), while mean Vitamin A levels were lowest in the deficiency group (226.6 ± 72.2 ng/mL) and highest in the normal group (263.3 ± 74.0 ng/mL). The study revealed a two-phase linear relationship with a significant threshold effect at a Vitamin D level of 28.289 ng/mL. Below this threshold, the association between Vitamin D and Vitamin A was strong (β = 2.935, 95% CI: 2.173, 3.696), while above the threshold, the association was significantly weaker (β = 0.737, 95% CI: 0.413, 1.061). The likelihood ratio test confirmed the significance of this threshold effect (p < 0.001).

Conclusion

The study concludes that a significant threshold at 28.289 ng/mL Vitamin D marks a point beyond which the association with Vitamin A levels plateaus, highlighting the importance of this threshold for optimizing vitamin status in children.

A New Conceptual Framework for Enhancing Vaccine Efficacy in Malnourished Children

Background

Malnourished children in low- and middle-income countries (LMICs) often exhibit reduced vaccine efficacy, particularly for oral vaccines like polio and rotavirus, due to impaired immune responses. Nutritional deficiencies, such as in vitamin A and zinc, along with environmental factors like poor sanitation, exacerbate this issue. Existing research has explored the individual impacts of malnutrition on vaccine outcomes, but a comprehensive framework that integrates nutritional, immune, and environmental factors has been lacking.

Objective

This article proposes a new conceptual framework that integrates nutritional status, immune function, and environmental context to explain the reduced vaccine efficacy in malnourished populations. The study highlights practical interventions to improve vaccine outcomes in these vulnerable populations.

Methods

A comprehensive literature review was conducted, focusing on vaccine efficacy in malnourished children, with data drawn from cross-sectional surveys, program evaluations, and peer-reviewed studies. Key interventions, including vitamin A supplementation, flexible immunization schedules, and environmental health programs, were analyzed for their impact on improving seroconversion rates.

Results

The review confirms that malnourished children exhibit significantly lower seroconversion rates for vaccines like oral polio and rotavirus, with a 30-40% reduction in efficacy for OPV and up to a 50% reduction for rotavirus. Nutritional interventions, particularly vitamin A supplementation, increased seroconversion rates by up to 30%, while flexible vaccination schedules and environmental improvements further enhanced vaccine responses in severely malnourished populations.

Conclusion

This framework addresses a critical gap in the literature by offering a holistic approach that integrates nutrition, immunization, and environmental health. Global health organizations, such as WHO and UNICEF, must prioritize the integration of nutrition and immunization programs, alongside environmental health initiatives, to reduce the burden of vaccine-preventable diseases in malnourished populations. Future research should focus on longitudinal studies to assess the long-term impact of these integrated interventions.

A systematic review and meta-analysis of the association between neglected tropical diseases and malnutrition: more research needed on diseases other than intestinal parasites, leishmaniasis and leprosy

Background. According to the World Health Organization, neglected tropical diseases (NTDs) affect over two billion people worldwide. While the links between nutrition and many diseases have become clear over recent decades, NTDs have lagged behind and the linkage with nutrition is largely unknown. We conducted this systematic review with meta-analysis to determine the current knowledge on the association between NTDs and malnutrition. Methodology. PubMed, Embase, Scopus and African Journals Online databases were searched using predefined search terms. We included all original articles with a case-control design and at least one NTD. The studies had to compare nutritional parameters between infected cases and control participants. Articles that did not report original data were excluded. The quality of the studies was assessed using the Newcastle-Ottawa scale. Pooled estimates were conducted using the random effect model. The publication bias of the studies was determined by funnel plots. Q and I 2 statistics were used to assess the heterogeneity of the studies. Results. After screening 1294 articles, only 16 qualified for the systematic review and 12 for meta-analysis. These predominately had a focus on soil-transmitted helminthiasis (ascariasis, hookworm diseases and trichuriasis) and schistosomiasis, with a minority concerning leishmaniasis and leprosy. Pooled estimates showed an association between intestinal parasites and stunting in children [odds ratio (OR) = 1.38, 95% confidence interval (CI): 1.14-1.66, I 2 = 0%, tau2 = 0]. We also identified a moderate association established between serum iron deficiency (OR = 4.67, 95% CI: 1.91-11.44, tau2 = 0) and intestinal parasites. Conclusions/significance. Of the 20 NTDs, the links between diet and disease have been explored for only 4. There is a paucity of data from low- and middle-income countries and least-developed countries where the NTD burden is high. Therefore, more research into the role of malnutrition in NTDs other than intestinal parasites, leishmaniasis and leprosy is needed.

Absolute and functional iron deficiency: Biomarkers, impact on immune system, and therapy

Iron is essential for numerous physiological processes and its deficiency often leads to anemia. Iron deficiency (ID) is a global problem, primarily affecting reproductive-age women and children, especially in developing countries. Diagnosis uses classical biomarkers like ferritin or transferrin saturation. Recent advancements include using soluble transferrin receptor (sTfR) or hepcidin for improved detection and classification of absolute and functional iron deficiencies, though mostly used in research. ID without anemia may present symptoms like asthenia and fatigue, even without relevant clinical consequences. ID impacts not only red-blood cells but also immune system cells, highlighting its importance in global health and immune-related comorbidities. Managing ID, requires addressing its cause and selecting appropriate iron supplementation. Various improved oral and intravenous products are available, but further research is needed to refine treatment strategies. This review updates on absolute and functional iron deficiencies, their relationships with the immune system and advancements in diagnosis and therapies.