Vitamin D, Gut Microbiota, and Cardiometabolic Diseases-A Possible Three-Way Axis

Vitamin D and Type 2 Diabetes Mellitus: Molecular Mechanisms and Clinical Implications-A Narrative Review

Vitamin D has been widely studied for its implications on type 2 diabetes mellitus, a chronic condition characterized by insulin resistance, inflammation, and metabolic dysfunction. This review explores the molecular mechanisms underpinning vitamin D's effects on glucose metabolism, inflammation, and adipogenesis, while assessing its potential clinical applications in type 2 diabetes. In its 1,25-dihydroxyvitamin D3 form, vitamin D modulates various metabolic processes, affecting proinflammatory cytokines and activating the AMPK pathway, inhibiting mTOR signaling, and promoting adipocyte differentiation. These effects enhance insulin sensitivity and reduce chronic inflammation, key contributors to metabolic dysfunction. In this context, the progression of prediabetes has been linked to vitamin D, which limits pathological progression and increases the likelihood of restoring a normal metabolic state, crucial in diabetes progression. Moreover, vitamin D has been reported to reduce the likelihood of developing diabetes by 15%, particularly in doses higher than the traditional recommendations for bone health. Despite promising evidence, discrepancies in study designs, serum vitamin D measurements, and population-specific factors highlight the need for standardized methodologies and personalized approaches. In conclusion, vitamin D has complementary therapeutic potential in treating type 2 diabetes, revealing gaps in research, such as optimal dosing and long-term effects across populations. Future studies should integrate molecular insights into clinical practice to optimize vitamin D's impact on metabolic health.

Valorizing Agro‐Food Waste for Nutraceutical Development: Sustainable Approaches for Managing Metabolic Dysfunction‐Associated Steatotic Liver Disease and Related Co‐Morbidities

This comprehensive investigation delves into the interconnectedness of different features of cardiometabolic syndrome, such as metabolic dysfunction‐associated steatotic liver disease (MASLD), atherosclerotic cardiovascular disease (ASCVD), and gut dysbiosis, highlighting the crucial role of nutraceuticals in their management and prevention. Given the significant overlap in the pathophysiology of these conditions, the treatment with nutraceuticals, especially those derived from agro‐food waste, offers a promising, sustainable, and innovative approach to healthcare. The 2030 Agenda for Sustainable Development and the One Health concept are key frameworks for selecting the most interesting supply chain for the production of nutraceuticals from agro‐food waste, ensuring environmental sustainability, and innovative agricultural practices. In this review, the therapeutic potential of kiwifruit and apples has been explored, detailing how their bioactive compounds, like polyphenols, fiber, pectin, kaempferol, phloretin, and phlorizin, may contribute to the management of MASLD, ASCVD, and gut dysbiosis. Various extraction methods for active ingredients, including chemical, water, and enzyme extractions, are analyzed for their respective benefits and drawbacks. By integrating scientific research, sustainable agricultural practices, and innovative extraction methods, we can develop effective strategies to combat these pervasive health issues. This holistic approach not only enhances individual health outcomes but also supports broader environmental and societal goals, promoting a healthier future for all.

Omega-3 Fatty Acid and Vitamin D Supplementations Partially Reversed Metabolic Disorders and Restored Gut Microbiota in Obese Wistar Rats

Obesity is a global public health issue linked to various comorbidities in both humans and animals. This study investigated the effects of vitamin D (VD) and omega-3 fatty acids (ω3FA) on obesity, gut dysbiosis, and metabolic alterations in Wistar rats. After 13 weeks on a standard (S) or High-Fat, High-Sugar (HFHS) diet, the rats received VD, ω3FA, a combination (VD/ω3), or a control (C) for another 13 weeks. The HFHS diet led to increased weight gain, abdominal circumference, glucose intolerance, insulin resistance, and gut dysbiosis. VD supplementation improved their fasting blood glucose and reduced liver damage, while ω3FA slowed BMI progression, reduced abdominal fat, liver damage, and intestinal permeability, and modulated the gut microbiota. The combination of VD/ω3 prevented weight gain, decreased abdominal circumference, improved glucose tolerance, and reduced triglycerides. This study demonstrates that VD and ω3FA, alone or combined, offer significant benefits in preventing obesity, gut dysbiosis, and metabolic alterations, with the VD/ω3 combination showing the most promise. Further research is needed to explore the mechanisms behind these effects and their long-term potential in both animal and human obesity management.

The Interplay between Liver and Adipose Tissue in the Onset of Liver Diseases: Exploring the Role of Vitamin Deficiency

The deficiency of vitamins, a condition known as "hidden hunger", causes comprehensive pathological states. Research over the years has identified a relationship between liver diseases and hypovitaminosis or defects in vitamin metabolism. The exact mechanisms remain elusive; however, the crucial involvement of specific vitamins in metabolic functions, alongside the reclassification of liver disease as metabolic dysfunction-associated steatotic liver disease (MASLD), has prompted researchers to investigate the potential cause-effect dynamics between vitamin deficiency and liver disease. Moreover, scientists are increasingly investigating how the deficiency of vitamins might disrupt specific organ crosstalk, potentially contributing to liver disease. Although the concept of a dysmetabolic circuit linking adipose tissue and the liver, leading to liver disease, has been discussed, the possible involvement of vitamin deficiency in this axis is a relatively recent area of study, with numerous critical aspects yet to be fully understood. In this review, we examine research from 2019 to July 2024 focusing on the possible link between liver-adipose tissue crosstalk and vitamin deficiency involved in the onset and progression of non-alcoholic fatty liver disease (NAFLD). Studies report that vitamin deficiency can affect the liver-adipose tissue axis, mainly affecting the regulation of systemic energy balance and inflammation.

Impact of vitamins A, D, and homocysteine on cardiometabolic multimorbidity in Northwest China

OBJECTIVE

To investigate the impact of vitamin A (VA), vitamin D (VD), and homocysteine (Hcy) on cardiometabolic multimorbidity (CMM).

METHODS

This study is a cross-sectional study conducted in Ningxia Province, China. A total of 5000 participants aged 25-74 were recruited and divided into two groups based on the definition of cardiometabolic multimorbidity: the CMM group and the Non CMM group. Demographic, lifestyle, and laboratory data were collected to investigate the correlation between vitamin A, D, Hcy levels and CMM risk. The association was analyzed using multiple logistic regression and restricted cubic spline method.

RESULTS

CMM incidence increased with age, being higher in females (20.05%) compared to males, Hypertension was present in 96.20% of CMM cases. Reduced VD levels correlated with an elevated CMM risk (OR = 1.799, 95% CI: 1.466-2.238), showing an inverse dose-response relationship, even after adjusting for confounders (OR = 1.553, 95% CI: 1.233-1.956). However, VA and Hcy levels were not significantly associated with CMM risk. The inverse correlation between VD status and CMM risk was more pronounced in males, obese individuals, and those with normal blood lipid profiles (P < 0.05).

CONCLUSIONS

The risk of CMM increases with age, especially in women. Inadequate VD status increases vulnerability to CMM, suggesting that optimising VD reduces the risk of CMM.

Investigating the Effects and Mechanisms of Combined Vitamin D and K Supplementation in Postmenopausal Women: An Up-to-Date Comprehensive Review of Clinical Studies

Aging is a complex process and a significant risk factor for chronic diseases. Menopause, a component of aging in women, is associated with several important cardiometabolic conditions including metabolic syndrome, osteoporosis, and cardiovascular diseases. Menopausal women could benefit from preventative strategies that may decrease morbidity and mortality and improve their quality of life. Vitamins D and K are essential nutrients required for bone health, immune function, and reducing cardiovascular risks, yet their synergistic effect is less understood in aging women. This is the first comprehensive review to summarize the evidence found in randomized clinical trials of the beneficial effects of vitamin D and K co-treatment in postmenopausal women. In our literature search across key electronic databases such as Cochrane, PubMed, and Ovid, we identified 31 pertinent studies. Overall, significant findings indicate that the combined intake of vitamins D and K may positively affect cardiovascular and bone health in postmenopausal women, emphasizing the importance of maintaining a healthy diet rich in vegetables and fermented dairy products. Given the challenges in obtaining all necessary nutrients solely through the diet, vitamin D and K supplements are recommended for postmenopausal women to promote healthy aging and well-being.

Induction of autism-related behavior in male mice by early-life vitamin D deficiency: association with disruption of the gut microbial composition and homeostasis

Vitamin D deficiency (VDD) during early life emerges as a potential risk factor for autism spectrum disorder (ASD). Individuals with autism commonly exhibit lower vitamin D (VD) levels compared to the general population, and VD deficiency is prevalent during pregnancy and lactation. Moreover, gastrointestinal comorbidity, prevalent in ASD patients, correlates closely with disruptions in the gut microbiota and altered intestinal permeability. Therefore, it is fascinating and significant to explore the effects of maternal VD deficiency during pregnancy and lactation on the maturation of the gut microbiota of the offspring and its relevance to autism spectrum disorders. In this study, we established maternal pregnancy and lactation VD-deficient mouse models, employed shotgun macrogenomic sequencing to unveil alterations in the gut microbiome of offspring mice, and observed autism-related behaviours. Furthermore, fecal microbial transplantation (FMT) reversed repetitive and anxious behaviours and alleviated social deficits in offspring mice by modulating the gut microbiota and increasing short-chain fatty acid levels in the cecum, along with influencing the concentrations of claudin-1 and occludin in the colon. Our findings confirm that VDD during pregnancy and lactation is a risk factor for autism in the offspring, with disturbances in the structure and function of the offspring's gut microbiota contributing at least part of the effect. The study emphasises the importance of nutrition and gut health early in life. Simultaneously, this study further demonstrates the effect of VDD on ASD and provides potential ideas for early prevention and intervention of ASD.

Vitamin D intervention as a curative measure for glucose intolerance in obese children and adolescents: a systematic review on randomized control trials

Vitamin D deficiency is associated with obesity and its associated metabolic disorders, as specified in many epidemiological studies. The assertion that vitamin D can mitigate insulin insensitivity in obese children and adolescents lacks adequate empirical substantiation. Thus, the study utilized some clinical trials on vitamin D interventions to examine the impact of vitamin D supplementation on insulin resistance in obese children and adolescents. The literature was extracted by applying the PRISMA method through electronic databases such as Scopus, Science Direct, Medline, the Cochrane Library, and PubMed from 2012 to 2022. All the articles were in English, and the inclusion criteria for each article were based on the study design and the anthropometric and biochemical parameters of the subjects. A total of 572 research articles were acquired, out of which only seven closely adhered to the inclusion criteria of the study. The studies in this systematic review are based on randomized control trials. The age range of the children in this study spans from 2 to 19 years, and the follow-up period ranges from 3 to 12 months. The range of daily vitamin D doses provided varied from 2000 to 10,000 IU. The results indicate that four randomized controlled trials have demonstrated a positive impact on glycemic parameters, such as insulin levels, fasting blood sugar, and insulin resistance, in the subjects following vitamin D treatment. However, the three trials did not provide sufficient evidence to support a statistically significant effect.

CONCLUSION

The present review highlights that a significant proportion of the studies incorporated in the analysis demonstrate that the administration of vitamin D may be a preventive measure in ameliorating insulin resistance among pediatric patients with obesity, but it is advisable to implement a prolonged intervention with a substantial sample size and perform micro-level analysis at the gene level to evaluate the impact of vitamin D treatment.

WHAT IS KNOWN

• Childhood obesity and its associated metabolic disorder is a concerned global problem. • Several studies showed an association of vitamin D deficiency with adiposity- induced metabolicdisorders which are still controversial. This study focused on finding interlink between vitamin Dsupplementation with obesity induced insulin resistance in children and adolescents.

WHAT IS NEW

• This study supports that high dosage of Vitamin D in long term may be protective against insulinresistance in obese paediatric individuals. • A new factor is also reported in the study that vitamin D may alter the composition of gut microbiotawhich represents a compelling approach to the therapeutic management of obesity and diabetes.

Modulation of the Gut Microbiota by Nutrition and Its Relationship to Epigenetics

The intestinal microbiota is a community of microorganisms inhabiting the human intestines, potentially influencing both physiological and pathophysiological processes in the human body. Existing evidence suggests that nutrients can influence the modulation of the gut microbiota. However, there is still limited evidence regarding the effects of vitamin and mineral supplementation on the human gut microbiota through epigenetic modification. It is plausible that maintaining an adequate dietary intake of vitamin D, iron, fibre, zinc and magnesium may have a beneficial effect on alleviating inflammation in the body, reducing oxidative stress, and improving the condition of the intestinal microbiota through various epigenetic mechanisms. Moreover, epigenetics involves alterations in the phenotype of a cell without changing its fundamental DNA sequence. It appears that the modulation of the microbiota by various nutrients may lead to epigenetic regulation. The correlations between microbiota and epigenetics are potentially interdependent. Therefore, the primary objective of this review is to identify the complex relationships between diet, gut microbiota, and epigenetic regulation. These interactions could play a crucial role in systemic health.

Nutrition at the Intersection between Gut Microbiota Eubiosis and Effective Management of Type 2 Diabetes

Nutrition is one of the most influential environmental factors in both taxonomical shifts in gut microbiota as well as in the development of type 2 diabetes mellitus (T2DM). Emerging evidence has shown that the effects of nutrition on both these parameters is not mutually exclusive and that changes in gut microbiota and related metabolites such as short-chain fatty acids (SCFAs) and branched-chain amino acids (BCAAs) may influence systemic inflammation and signaling pathways that contribute to pathophysiological processes associated with T2DM. With this background, our review highlights the effects of macronutrients, carbohydrates, proteins, and lipids, as well as micronutrients, vitamins, and minerals, on T2DM, specifically through their alterations in gut microbiota and the metabolites they produce. Additionally, we describe the influences of common food groups, which incorporate varying combinations of these macronutrients and micronutrients, on both microbiota and metabolic parameters in the context of diabetes mellitus. Overall, nutrition is one of the first line modifiable therapies in the management of T2DM and a better understanding of the mechanisms by which gut microbiota influence its pathophysiology provides opportunities for optimizing dietary interventions.

Microbial metabolites as modulators of host physiology

The gut microbiota is increasingly recognised as a key player in influencing human health and changes in the gut microbiota have been strongly linked with many non-communicable conditions in humans such as type 2 diabetes, obesity and cardiovascular disease. However, characterising the molecular mechanisms that underpin these associations remains an important challenge for researchers. The gut microbiota is a complex microbial community that acts as a metabolic interface to transform ingested food (and other xenobiotics) into metabolites that are detected in the host faeces, urine and blood. Many of these metabolites are only produced by microbes and there is accumulating evidence to suggest that these microbe-specific metabolites do act as effectors to influence human physiology. For example, the gut microbiota can digest dietary complex polysaccharides (such as fibre) into short-chain fatty acids (SCFA) such as acetate, propionate and butyrate that have a pervasive role in host physiology from nutrition to immune function. In this review we will outline our current understanding of the role of some key microbial metabolites, such as SCFA, indole and bile acids, in human health. Whilst many studies linking microbial metabolites with human health are correlative we will try to highlight examples where genetic evidence is available to support a specific role for a microbial metabolite in host health and well-being.

The imprecision of micronutrient requirement values: the example of vitamin D

Food, not nutrients, is the fundamental unit in nutrition. Nutrient requirement values and recommended daily intakes have long been determined and organized in tables by several regulators. These figures, however, overlook the complexity of mixing different foods in a diet and the mediation by human gut microbiota on digestion, metabolism, and health. The microbiome molecular mechanisms and its potential influence on nutrient requirements are far from clear. Guidelines should depend on the sort of intake, along with the dietary habits, rather than focusing on single nutrients. Despite many decades of attempts to investigate the proximate nutrient composition of foods consumed by different world populations, there are still neither standardization of food composition databases nor harmonized dietary intake methods of assessment of nutrients. No all-inclusive attempt was yet made to emphasize the requirements of the various micronutrients, phytonutrients, and non-nutrients on gut microbiota and vice versa, and thereafter reflected into dietary guidelines. New multifaceted methods have been advanced to reevaluate the way nutrients and nutrient requirements are assessed within the intricate biological systems. Our main goal here was to enhance the fact that existing food guidelines hold inherent strengths and limitations but fail, in many aspects, namely, in not taking into account essential geographical, ethnic and cultural differences, and the different stages of life, infant nutrition, and the microbiota impact on several micronutrient requirements. Vitamin D is given as an illustration on present inaccuracy of its requirements. Defining dietary reference intakes is therefore an ongoing process specific for each population.

Neuroimmunological Effect of Vitamin D on Neuropsychiatric Long COVID Syndrome: A Review

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of the coronavirus disease 2019 (COVID-19). COVID-19 is now recognized as a multiorgan disease with a broad spectrum of manifestations. A substantial proportion of individuals who have recovered from COVID-19 are experiencing persistent, prolonged, and often incapacitating sequelae, collectively referred to as long COVID. To date, definitive diagnostic criteria for long COVID diagnosis remain elusive. An emerging public health threat is neuropsychiatric long COVID, encompassing a broad range of manifestations, such as sleep disturbance, anxiety, depression, brain fog, and fatigue. Although the precise mechanisms underlying the neuropsychiatric complications of long COVID are presently not fully elucidated, neural cytolytic effects, neuroinflammation, cerebral microvascular compromise, breakdown of the blood-brain barrier (BBB), thrombosis, hypoxia, neurotransmitter dysregulation, and provoked neurodegeneration are pathophysiologically linked to long-term neuropsychiatric consequences, in addition to systemic hyperinflammation and maladaptation of the renin-angiotensin-aldosterone system. Vitamin D, a fat-soluble secosteroid, is a potent immunomodulatory hormone with potential beneficial effects on anti-inflammatory responses, neuroprotection, monoamine neurotransmission, BBB integrity, vasculometabolic functions, gut microbiota, and telomere stability in different phases of SARS-CoV-2 infection, acting through both genomic and nongenomic pathways. Here, we provide an up-to-date review of the potential mechanisms and pathophysiology of neuropsychiatric long COVID syndrome and the plausible neurological contributions of vitamin D in mitigating the effects of long COVID.

Dietary Patterns, Gut Microbiota Remodeling, and Cardiometabolic Disease

The cardiovascular and metabolic disorders, collectively known as cardiometabolic disease (CMD), are high morbidity and mortality pathologies associated with lower quality of life and increasing health-care costs. The influence of the gut microbiota (GM) in dictating the interpersonal variability in CMD susceptibility, progression and treatment response is beginning to be deciphered, as is the mutualistic relation established between the GM and diet. In particular, dietary factors emerge as pivotal determinants shaping the architecture and function of resident microorganisms in the human gut. In turn, intestinal microbes influence the absorption, metabolism, and storage of ingested nutrients, with potentially profound effects on host physiology. Herein, we present an updated overview on major effects of dietary components on the GM, highlighting the beneficial and detrimental consequences of diet-microbiota crosstalk in the setting of CMD. We also discuss the promises and challenges of integrating microbiome data in dietary planning aimed at restraining CMD onset and progression with a more personalized nutritional approach.

Editorial of Special Issue "The Role of Vitamin D in Human Health and Diseases 2.0"

Vitamin D performs a differentiating, metabolic and anti-inflammatory function, through genomic, non-genomic and mitochondrial mechanisms of action [...].

Role of Vitamins in Cardiovascular Health: Know Your Facts-Part 2

Cardiovascular disease (CVD) is a major cause of morbidity/mortality world-wide, hence preventive interventions are crucial. Observational data showing beneficial CV effects of vitamin supplements, promoted by self-proclaimed experts, have led to ~50% of Americans using multivitamins; this practice has culminated into a multi-billion-dollar business. However, robust evidence is lacking, and certain vitamins might incur harm. This two-part review focuses on the attributes or concerns about specific vitamin consumption on CVD. The evidence for indiscriminate use of multivitamins indicates no consistent CVD benefit. Specific vitamins and/or combinations are suggested, but further supportive evidence is needed. Data presented in Part 1 indicated that folic acid and certain B-vitamins may decrease stroke, whereas niacin might raise mortality; beta-carotene mediates pro-oxidant effects, which may abate the benefits from other vitamins. In Part 2, data favor the anti-oxidant effects of vitamin C and the anti-atherogenic effects of vitamins C and E, but clinical evidence is inconsistent. Vitamin D may provide CV protection, but data are conflicting. Vitamin K appears neutral. Thus, there are favorable CV effects of individual vitamins (C/D), but randomized/controlled data are lacking. An important caveat regards the potential toxicity of increased doses of fat-soluble vitamins (A/D/E/K). As emphasized in Part 1, vitamins might benefit subjects who are antioxidant-deficient or exposed to high levels of oxidative-stress (e.g., diabetics, smokers, and elderly), stressing the importance of targeting certain subgroups for optimal results. Finally, by promoting CV-healthy balanced-diets, we could acquire essential vitamins and nutrients and use supplements only for specific indications.