Silvia Maggini

Contribution of selected vitamins and trace elements to immune function.

Adequate intakes of vitamins and trace elements are required for the immune system to function efficiently. Micronutrient deficiency suppresses immune functions by affecting the innate T-cell-mediated immune response and adaptive antibody response, and leads to dysregulation of the balanced host response. This increases the susceptibility to infections, with increased morbidity and mortality. In turn, infections aggravate micronutrient deficiencies by reducing nutrient intake, increasing losses, and interfering with utilization by altering metabolic pathways. Insufficient intake of micronutrients occurs in people with eating disorders, in smokers (both active and passive), in individuals with chronic alcohol abuse, in patients with certain diseases, during pregnancy and lactation, and in the elderly. With aging a variety of changes are observed in the immune system, which translate into less effective innate and adaptive immune responses and increased susceptibility to infections. Antioxidant vitamins and trace elements (vitamins C, E, selenium, copper, and zinc) counteract potential damage caused by reactive oxygen species to cellular tissues and modulate immune cell function through regulation of redox-sensitive transcription factors and affect production of cytokines and prostaglandins. Adequate intake of vitamins B6, folate, B12, C, E, and of selenium, zinc, copper, and iron supports a Th1 cytokine-mediated immune response with sufficient production of proinflammatory cytokines, which maintains an effective immune response and avoids a shift to an anti-inflammatory Th2 cell-mediated immune response and an increased risk of extracellular infections. Supplementation with these micronutrients reverses the Th2 cell-mediated immune response to a proinflammatory Th1 cytokine-regulated response with enhanced innate immunity. Vitamins A and D play important roles in both cell-mediated and humoral antibody response and support a Th2-mediated anti-inflammatory cytokine profile. Vitamin A deficiency impairs both innate immunity (mucosal epithelial regeneration) and adaptive immune response to infection resulting in an impaired ability to counteract extracellular pathogens. Vitamin D deficiency is correlated with a higher susceptibility to infections due to impaired localized innate immunity and defects in antigen-specific cellular immune response. Overall, inadequate intake and status of these vitamins and minerals may lead to suppressed immunity, which predisposes to infections and aggravates malnutrition.

Selected vitamins and trace elements support immune function by strengthening epithelial barriers and cellular and humoral immune responses

Adequate intakes of micronutrients are required for the immune system to function efficiently. Micronutrient deficiency suppresses immunity by affecting innate, T cell mediated and adaptive antibody responses, leading to dysregulation of the balanced host response. This situation increases susceptibility to infections, with increased morbidity and mortality. In turn, infections aggravate micronutrient deficiencies by reducing nutrient intake, increasing losses, and interfering with utilization by altering metabolic pathways. Insufficient intake of micronutrients occurs in people with eating disorders, in smokers (active and passive), in individuals with chronic alcohol abuse, in certain diseases, during pregnancy and lactation, and in the elderly. This paper summarises the roles of selected vitamins and trace elements in immune function. Micronutrients contribute to the bodys natural defences on three levels by supporting physical barriers (skin/mucosa), cellular immunity and antibody production. Vitamins A, C, E and the trace element zinc assist in enhancing the skin barrier function. The vitamins A, B6, B12, C, D, E and folic acid and the trace elements iron, zinc, copper and selenium work in synergy to support the protective activities of the immune cells. Finally, all these micronutrients, with the exception of vitamin C and iron, are essential for antibody production. Overall, inadequate intake and status of these vitamins and trace elements may lead to suppressed immunity, which predisposes to infections and aggravates malnutrition. Therefore, supplementation with these selected micronutrients can support the bodys natural defence system by enhancing all three levels of immunity.

Immune-enhancing role of vitamin C and zinc and effect on clinical conditions.

Vitamin C concentrations in the plasma and leukocytes rapidly decline during infections and stress. Supplementation of vitamin C was found to improve components of the human immune system such as antimicrobial and natural killer cell activities, lymphocyte proliferation, chemotaxis, and delayed-type hypersensitivity. Vitamin C contributes to maintaining the redox integrity of cells and thereby protects them against reactive oxygen species generated during the respiratory burst and in the inflammatory response. Likewise, zinc undernutrition or deficiency was shown to impair cellular mediators of innate immunity such as phagocytosis, natural killer cell activity, and the generation of oxidative burst. Therefore, both nutrients play important roles in immune function and the modulation of host resistance to infectious agents, reducing the risk, severity, and duration of infectious diseases. This is of special importance in populations in which insufficient intake of these nutrients is prevalent. In the developing world, this is the case in low- and middle-income countries, but also in subpopulations in industrialized countries, e.g. in the elderly. A large number of randomized controlled intervention trials with intakes of up to 1 g of vitamin C and up to 30 mg of zinc are available. These trials document that adequate intakes of vitamin C and zinc ameliorate symptoms and shorten the duration of respiratory tract infections including the common cold. Furthermore, vitamin C and zinc reduce the incidence and improve the outcome of pneumonia, malaria, and diarrhea infections, especially in children in developing countries.

Effects of a multi-vitamin/mineral supplement on cognitive function and fatigue during extended multi-tasking

A significant minority of the population consume multi‐vitamins/minerals for their putative health benefits, including potentially beneficial effects on cognitive performance, fatigue and mood. The current study investigated the effect of supplementation with a multi‐vitamin/mineral on fatigue and cognitive function in healthy females.

Vitamin C and Immune Function

Vitamin C is an essential micronutrient for humans, with pleiotropic functions related to its ability to donate electrons. It is a potent antioxidant and a cofactor for a family of biosynthetic and gene regulatory enzymes. Vitamin C contributes to immune defense by supporting various cellular functions of both the innate and adaptive immune system. Vitamin C supports epithelial barrier function against pathogens and promotes the oxidant scavenging activity of the skin, thereby potentially protecting against environmental oxidative stress. Vitamin C accumulates in phagocytic cells, such as neutrophils, and can enhance chemotaxis, phagocytosis, generation of reactive oxygen species, and ultimately microbial killing. It is also needed for apoptosis and clearance of the spent neutrophils from sites of infection by macrophages, thereby decreasing necrosis/NETosis and potential tissue damage. The role of vitamin C in lymphocytes is less clear, but it has been shown to enhance differentiation and proliferation of B- and T-cells, likely due to its gene regulating effects. Vitamin C deficiency results in impaired immunity and higher susceptibility to infections. In turn, infections significantly impact on vitamin C levels due to enhanced inflammation and metabolic requirements. Furthermore, supplementation with vitamin C appears to be able to both prevent and treat respiratory and systemic infections. Prophylactic prevention of infection requires dietary vitamin C intakes that provide at least adequate, if not saturating plasma levels (i.e., 100–200 mg/day), which optimize cell and tissue levels. In contrast, treatment of established infections requires significantly higher (gram) doses of the vitamin to compensate for the increased inflammatory response and metabolic demand.

Acute effects of different multivitamin mineral preparations with and without guarana on mood, cognitive performance and functional brain activation

Previous work has identified the positive effects of the acute administration of a multivitamin-guaraná preparation during an effortful executive/working memory task. Here, we aimed to differentiate the effects of multivitamins with and without guaraná and to examine the neural substrates of such effects using functional magnetic resonance imaging (fMRI). Following a double-blind, placebo-controlled, randomised, balanced crossover design, 20 participants (mean age 29 ± 5.54 years) consumed multivitamin preparations with or without guaraná (Berocca® Performance and Boost, respectively) and a placebo. Thirty minutes post-treatment, they underwent neurocognitive assessment, consisting of a 10 min Cognitive Demand Battery, with mood ratings taken immediately before and after the battery. Five additional participants underwent post-treatment fMRI scanning during Rapid Visual Information Processing and Inspection Time activation tasks. The multivitamin with guaraná treatment was associated with significantly enhanced Serial Threes performance and self-rated contentment. fMRI revealed that both multivitamin treatments increased activation in areas associated with working memory and attentional processing, with the effect being greater in the multivitamin with guaraná condition. These data confirm the acute benefits of multivitamins with guaraná on mood and cognitive performance. Furthermore, they demonstrate for the first time increased brain activation from multivitamin preparations both with and without guaraná, as measured using fMRI.

The effect of a single dose of multivitamin and mineral combinations with and without guaraná on functional brain activity during a continuous performance task

Objectives: Relatively few studies have explored the possibility of acute cognitive effects of multivitamin ingestion. This report explores the acute brain electrophysiological changes associated with multivitamin and mineral supplementation, with and without guaraná, using the steady-state visually evoked potential (SSVEP). Methods: Based on the known SSVEP correlates of A-X continuous performance task (CPT) performance, and sensitivity to acute psychopharmacological manipulations, the A-X CPT was adopted as a task paradigm to explore treatment-related neurophysiological changes in attentional processing. Twenty healthy non-smoking adults aged 21–39 years (mean age = 28.35 years, SD = 5.52) took part in this double-blind, placebo-controlled, randomized, balanced crossover design study. Results: The study demonstrated both transient and tonic changes in the SSVEP response during completion of the A-X CPT following multivitamin and mineral treatment both with and without guaraná. Transient changes in SSVEP response in prefrontal regions were observed after a single dose of a multivitamin and mineral preparation indicative of enhanced activity within brain regions engaged by the attentional demands of the task. This pattern of change in frontal regions was correlated with improved behavioural performance after treatment with the multivitamin and mineral combination. Where tonic shifts in SSVEP response were investigated, multivitamin and mineral treatment was associated with a pattern of increased inhibition across posterior regions, with enhanced excitatory processing in prefrontal regions. In contrast, multivitamin and mineral treatment with additional guaraná showed a tonic shift towards greater excitatory processes after a single treatment, consistent with the caffeine content of this treatment. Discussion: While preliminary in nature, these findings suggest a single multivitamin/mineral dose is sufficient to impact on functional brain activity in task-related brain regions.

Multivitamin Supplementation Supports Immune Function andAmeliorates Conditions Triggered By Reduced Air Quality

Our bodies are normally well protected against continual attack from pathogens and noxious insult by a complex and integrated immune system. However, daily bombardment from indoor and outdoor air pollutants can compromise immune function and ultimately lead to infection (e.g. acute respiratory tract infections, diarrhoea) and conditions such as sick building syndrome (with mucosal, skin and general symptoms). All of us may be affected by reduced air quality, although certain factors increase the risk of impaired immunity (e.g. young or advancing age, exposure to tobacco smoke, close proximity to areas of high air pollution, office work, commuting). A major exogenous factor modulating immune function is nutrition; even subclinical deficiencies in various nutrients can have adverse effects on the immune system, which may be exacerbated by environmental threats. In particular, the oxidant-antioxidant balance (vital for communication within the immune system) may be affected. Dietary supplementation can help to restore immune function to the normal range, and an antioxidant-containing multivitamin supplement has been shown to ameliorate the symptoms of sick building syndrome, acute respiratory tract infections and diarrhoea. This review looks at the impact of reduced air quality on the oxidant-antioxidant balance and the role of selected micronutrients (vitamins A, D, E, C, B6, B12, folate and the trace elements copper, iron, selenium and zinc) and multivitamin supplementation.

The Effects of Supplementation with a Vitamin and Mineral Complex with Guaraná Prior to Fasted Exercise on Affect, Exertion, Cognitive Performance, and Substrate Metabolism: A Randomized Controlled Trial

Exercise undertaken in a fasted state can lead to higher post-exercise mental fatigue. The administration of a vitamin and mineral complex with guaraná (MVM + G) has been shown to attenuate mental fatigue and improve performance during cognitively demanding tasks. This placebo-controlled, double-blind, randomized, balanced cross-over study examined the effect of MVM + G consumed prior to morning exercise on cognitive performance, affect, exertion, and substrate metabolism. Forty active males (age 21.4 ± 3.0 year; body mass index (BMI) 24.0 ± 2.4 kg/m2; maximal oxygen consumption (V̇O2max) 57.6 ± 7.3 mL/min/kg) completed two main trials, consuming either MVM + G or placebo prior to a 30-min run at 60% V̇O2max. Supplementation prior to exercise led to a small but significant reduction in Rating of Perceived Exertion (RPE) during exercise compared to the placebo. The MVM + G combination also led to significantly increased accuracy of numeric working memory and increased speed of picture recognition, compared to the placebo. There were no significant effects of supplementation on any other cognitive or mood measures or on substrate metabolism during exercise. These findings demonstrate that consuming a vitamin and mineral complex containing guaraná, prior to exercise, can positively impact subsequent memory performance and reduce perceived exertion during a moderate-intensity run in active males.

Immune-enhancing role of vitamin C and zinc and effect on clinical conditions

Vitamin C concentrations in the plasma and leukocytes rapidly decline during infections and stress. Supplementation of vitamin C was found to improve components of the human immune system such as antimicrobial and natural killer cell activities, lymphocyte proliferation, chemotaxis, and delayed-type hypersensitivity. Vitamin C contributes to maintaining the redox integrity of cells and thereby protects them against reactive oxygen species generated during the respiratory burst and in the inflammatory response. Likewise, zinc undernutrition or deficiency was shown to impair cellular mediators of innate immunity such as phagocytosis, natural killer cell activity, and the generation of oxidative burst. Therefore, both nutrients play important roles in immune function and the modulation of host resistance to infectious agents, reducing the risk, severity, and duration of infectious diseases. This is of special importance in populations in which insufficient intake of these nutrients is prevalent. In the developing world, this is the case in lowand middle-income countries, but also in subpopulations in industrialized countries, e.g. in the elderly. A large number of randomized controlled intervention trials with intakes of up to 1 g of vitamin C and up to 30 mg of zinc are available. These trials document that adequate intakes of vitamin C and zinc ameliorate symptoms and shorten the duration of respiratory tract infections including the common cold. Furthermore, vitamin C and zinc reduce the incidence and improve the outcome of pneumonia, malaria, and diarrhea infections, especially in children in developing countries. PMID: 16373990 DOI: 10.1159/000090495 [Indexed for MEDLINE] Format: Abstract 1 Author information PubMed Full text links Immune-enhancing role of vitamin C and zinc and effect on clin... https://www.ncbi.nlm.nih.gov/pubmed/16373990 1 of 2 2/13/18, 7:33 PM