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1.
Physical Activity and Diet Shape the Immune System during Aging.
Weyh, C, Krüger, K, Strasser, B
Nutrients. 2020;(3)
Abstract
With increasing age, the immune system undergoes a remodeling process, termed immunosenescence, which is accompanied by considerable shifts in leukocyte subpopulations and a decline in various immune cell functions. Clinically, immunosenescence is characterized by increased susceptibility to infections, a more frequent reactivation of latent viruses, decreased vaccine efficacy, and an increased prevalence of autoimmunity and cancer. Physiologically, the immune system has some adaptive strategies to cope with aging, while in some settings, maladaptive responses aggravate the speed of aging and morbidity. While a lack of physical activity, decreased muscle mass, and poor nutritional status facilitate immunosenescence and inflammaging, lifestyle factors such as exercise and dietary habits affect immune aging positively. This review will discuss the relevance and mechanisms of immunoprotection through physical activity and specific exercise interventions. In the second part, we will focus on the effect of dietary interventions through the supplementation of the essential amino acid tryptophan, n-3 polyunsaturated fatty acids, and probiotics (with a special focus on the kynurenine pathway).
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2.
Vitamin D Effects on the Immune System from Periconception through Pregnancy.
Schröder-Heurich, B, Springer, CJP, von Versen-Höynck, F
Nutrients. 2020;(5)
Abstract
Vitamin D is a well-known secosteroid and guardian of bone health and calcium homeostasis. Studies on its role in immunomodulatory functions have expanded its field in recent years. In addition to its impact on human physiology, vitamin D influences the differentiation and proliferation of immune system modulators, interleukin expression and antimicrobial responses. Furthermore, it has been shown that vitamin D is synthesized in female reproductive tissues and, by modulating the immune system, affects the periconception period and reproductive outcomes. B cells, T cells, macrophages and dendritic cells can all synthesize active vitamin D and are involved in processes which occur from fertilization, implantation and maintenance of pregnancy. Components of vitamin D synthesis are expressed in the ovary, decidua, endometrium and placenta. An inadequate vitamin D level has been associated with recurrent implantation failure and pregnancy loss and is associated with pregnancy-related disorders like preeclampsia. This paper reviews the most important data on immunomodulatory vitamin D effects in relation to the immune system from periconception to pregnancy and provides an insight into the possible consequences of vitamin D deficiency before and during pregnancy.
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3.
Dietary Regulation of Immunity.
Lee, AH, Dixit, VD
Immunity. 2020;(3):510-523
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Abstract
Integrated immunometabolic responses link dietary intake, energy utilization, and storage to immune regulation of tissue function and is therefore essential for the maintenance and restoration of homeostasis. Adipose-resident leukocytes have non-traditional immunological functions that regulate organismal metabolism by controlling insulin action, lipolysis, and mitochondrial respiration to control the usage of substrates for production of heat versus ATP. Energetically expensive vital functions such as immunological responses might have thus evolved to respond accordingly to dietary surplus and deficit of macronutrient intake. Here, we review the interaction of dietary intake of macronutrients and their metabolism with the immune system. We discuss immunometabolic checkpoints that promote healthspan and highlight how dietary fate and regulation of glucose, fat, and protein metabolism might affect immunity.
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4.
Impact of Epigenetics on Complications of Fanconi Anemia: The Role of Vitamin D-Modulated Immunity.
Velleuer, E, Carlberg, C
Nutrients. 2020;(5)
Abstract
Fanconi anemia (FA) is a rare disorder with the clinical characteristics of (i) specific malformations at birth, (ii) progressive bone marrow failure already during early childhood and (iii) dramatically increased risk of developing cancer in early age, such as acute myeloid leukemia and squamous cell carcinoma. Patients with FA show DNA fragility due to a defect in the DNA repair machinery based on predominately recessive mutations in 23 genes. Interestingly, patients originating from the same family and sharing an identical mutation, frequently show significant differences in their clinical presentation. This implies that epigenetics plays an important role in the manifestation of the disease. The biologically active form of vitamin D, 1α,25-dihydroxyvitamin D3 controls cellular growth, differentiation and apoptosis via the modulation of the immune system. The nuclear hormone activates the transcription factor vitamin D receptor that affects, via fine-tuning of the epigenome, the transcription of >1000 human genes. In this review, we discuss that changes in the epigenome, in particular in immune cells, may be central for the clinical manifestation of FA. These epigenetic changes can be modulated by vitamin D suggesting that the individual FA patient's vitamin D status and responsiveness are of critical importance for disease progression.
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5.
Inadequacy of Immune Health Nutrients: Intakes in US Adults, the 2005-2016 NHANES.
Reider, CA, Chung, RY, Devarshi, PP, Grant, RW, Hazels Mitmesser, S
Nutrients. 2020;(6)
Abstract
A well-functioning immune system is essential for human health and well-being. Micronutrients such as vitamins A, C, D, E, and zinc have several functions throughout the immune system, yet inadequate nutrient intakes are pervasive in the US population. A large body of research shows that nutrient inadequacies can impair immune function and weaken the immune response. Here, we present a new analysis of micronutrient usual intake estimates based on nationally representative data in 26,282 adults (>19 years) from the 2005-2016 National Health and Nutrition Examination Surveys (NHANES). Overall, the prevalence of inadequacy (% of population below estimated average requirement [EAR]) in four out of five key immune nutrients is substantial. Specifically, 45% of the U.S. population had a prevalence of inadequacy for vitamin A, 46% for vitamin C, 95% for vitamin D, 84% for vitamin E, and 15% for zinc. Dietary supplements can help address nutrient inadequacy for these immune-support nutrients, demonstrated by a lower prevalence of individuals below the EAR. Given the long-term presence and widening of nutrient gaps in the U.S.-specifically in critical nutrients that support immune health-public health measures should adopt guidelines to ensure an adequate intake of these micronutrients. Future research is needed to better understand the interactions and complexities of multiple nutrient shortfalls on immune health and assess and identify optimal levels of intake in at-risk populations.
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6.
Development of child immunity in the context of COVID-19 pandemic.
Kloc, M, Ghobrial, RM, Kuchar, E, Lewicki, S, Kubiak, JZ
Clinical immunology (Orlando, Fla.). 2020;:108510
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Abstract
Children, because of having an immature immune system, are usually more prone than the adults to the microbial infections and have more severe symptoms, which is especially true for the newborns, and very young children. However, the review of clinical data from the current COVID-19 pandemic indicates otherwise. We discuss here what are the main features and components of children's immune system, the role of maternal transmission of immunity, and what are the possible explanations for the seemingly lower infection rate and severity of COVI-19 in children.
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7.
Understanding immune variation for improved translational medicine.
Duffy, D
Current opinion in immunology. 2020;:83-88
Abstract
The goal of translational medicine is to use an improved understanding of human biology to develop new clinical approaches. Immune responses are highly variable from one person to another, with this variability strongly impacting clinical outcome. Variable immunity can determine differential risks for infection, for development of autoimmunity, and for response to therapeutic interventions. Therefore, a better understanding of the causes of such differences has huge potential to improve patient management through precision medicine strategies. Variability in immunity is determined by intrinsic (e.g. age, sex), extrinsic (e.g. environment, diet), and genetic factors. There is a growing consensus that genetics factors account for 20-40% of immune variability between individuals. The remaining unexplained variability is likely due to direct environmental influences, as well as specific gene-environmental interactions, which are more challenging to quantify and study. However, population based cohort studies with systems immunology approaches are now providing new understanding into these associations.
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Modulation of the Gut Microbiota by Olive Oil Phenolic Compounds: Implications for Lipid Metabolism, Immune System, and Obesity.
Farràs, M, Martinez-Gili, L, Portune, K, Arranz, S, Frost, G, Tondo, M, Blanco-Vaca, F
Nutrients. 2020;(8)
Abstract
There is extensive information of the beneficial effects of virgin olive oil (VOO), especially on cardiovascular diseases. Some VOO healthy properties have been attributed to their phenolic-compounds (PCs). The aim of this review is to present updated data on the effects of olive oil (OO) PCs on the gut microbiota, lipid metabolism, immune system, and obesity, as well as on the crosstalk among them. We summarize experiments and clinical trials which assessed the specific effects of the olive oil phenolic-compounds (OOPCs) without the synergy with OO-fats. Several studies have demonstrated that OOPC consumption increases Bacteroidetes and/or reduces the Firmicutes/Bacteroidetes ratio, which have both been related to atheroprotection. OOPCs also increase certain beneficial bacteria and gut-bacteria diversity which can be therapeutic for lipid-immune disorders and obesity. Furthermore, some of the mechanisms implicated in the crosstalk between OOPCs and these disorders include antimicrobial-activity, cholesterol microbial metabolism, and metabolites produced by bacteria. Specifically, OOPCs modulate short-chain fatty-acids produced by gut-microbiota, which can affect cholesterol metabolism and the immune system, and may play a role in weight gain through promoting satiety. Since data in humans are scarce, there is a necessity for more clinical trials designed to assess the specific role of the OOPCs in this crosstalk.
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Microbiota and Diabetes Mellitus: Role of Lipid Mediators.
Salazar, J, Angarita, L, Morillo, V, Navarro, C, Martínez, MS, Chacín, M, Torres, W, Rajotia, A, Rojas, M, Cano, C, et al
Nutrients. 2020;(10)
Abstract
Diabetes Mellitus (DM) is an inflammatory clinical entity with different mechanisms involved in its physiopathology. Among these, the dysfunction of the gut microbiota stands out. Currently, it is understood that lipid products derived from the gut microbiota are capable of interacting with cells from the immune system and have an immunomodulatory effect. In the presence of dysbiosis, the concentration of lipopolysaccharides (LPS) increases, favoring damage to the intestinal barrier. Furthermore, a pro-inflammatory environment prevails, and a state of insulin resistance and hyperglycemia is present. Conversely, during eubiosis, the production of short-chain fatty acids (SCFA) is fundamental for the maintenance of the integrity of the intestinal barrier as well as for immunogenic tolerance and appetite/satiety perception, leading to a protective effect. Additionally, it has been demonstrated that alterations or dysregulation of the gut microbiota can be reversed by modifying the eating habits of the patients or with the administration of prebiotics, probiotics, and symbiotics. Similarly, different studies have demonstrated that drugs like Metformin are capable of modifying the composition of the gut microbiota, promoting changes in the biosynthesis of LPS, and the metabolism of SCFA.
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10.
Vitamin D's Effect on Immune Function.
Martens, PJ, Gysemans, C, Verstuyf, A, Mathieu, AC
Nutrients. 2020;(5)
Abstract
Ever since its discovery by Windhaus, the importance of the active metabolite of vitamin D (1,25-dihydroxyvitamin D3; 1,25-(OH)2D3) has been ever expanding. In this review, the attention is shifted towards the importance of the extra-skeletal effects of vitamin D, with special emphasis on the immune system. The first hint of the significant role of vitamin D on the immune system was made by the discovery of the presence of the vitamin D receptor on almost all cells of the immune system. In vitro, the overwhelming effect of supra-physiological doses of vitamin D on the individual components of the immune system is very clear. Despite these promising pre-clinical results, the translation of the in vitro observations to solid clinical effects has mostly failed. Nevertheless, the evidence of a link between vitamin D deficiency and adverse outcomes is overwhelming and clearly points towards avoidance of vitamin D deficiency especially in early life.