People who are depressed have lower concentrations of zinc in their peripheral blood compared with nondepressed individuals, a meta-analysis suggests.
"The pathophysiological relationships between zinc status and depression, and the potential benefits of zinc supplementation in depressed patients, warrant further investigation," write Walter Swardfager, PhD, from the Sunnybrook Research Institute, University of Toronto, Canada, and colleagues.
Their findings were published in the December 15 issue of Biological Psychiatry.
Link to Zinc Deficiency
"A growing body of evidence demonstrates that experimental zinc deficiency can induce depressive-like behavior in animals, which can be effectively reversed by zinc supplementation," the authors write. Furthermore, preliminary clinical trials have suggested that zinc added to antidepressant therapy may produce more rapid or more effective improvement in depressive symptoms.
Many, although not all, studies that have measured zinc concentrations of peripheral blood in depressed and nondepressed individuals during the past several decades have suggested that depression might be associated with lower zinc concentrations in various population samples, the researchers note.
The aim of this meta-analysis was to determine whether the clinical evidence collectively supports lower zinc concentrations in depressed patients compared with nondepressed individuals.
The analysis included 17 studies that measured peripheral blood–zinc concentrations in 1643 depressed patients and 804 control participants. Ten of these studies reported on psychiatric inpatients, and 7 reported on community samples. Of the participants, 34.4% were male; the mean age was 37.7 years.
The researchers found that mean peripheral blood–zinc concentrations were lower by approximately 1.85 µmol/L in depressed individuals compared with control participants (95% confidence interval [CI], -2.51 to -1.19; P < .00001).
More severe depression was associated with greater differences in zinc levels between depressed and control participants (P = .026).
Further, the authors report that effect sizes were larger in studies of inpatients (weighted mean difference [WMD], -2.543; 95% CI, -3.522 to -1.564; P < .0001) vs community samples (WMD, -.943; 95% CI, -1.563 to -.323; P = .003) and in studies with higher methodologic quality (WMD, -2.354; 95% CI, -2.901 to -1.807; P < .0001).
Biologically Plausible
"Although association studies cannot determine the direction of causation, a causal association between zinc status and depression is biologically plausible," the authors write.
"Zinc has antioxidant properties, helps to maintain endocrine homeostasis and immune function, and plays multiple roles in regulating the hippocampal and cortical glutamatergic circuits that subserve affective regulation and cognitive function. Thus, changes in zinc homeostasis might compromise neuroplasticity and contribute to long-term neuropsychological and psychiatric decline," they write.
Zinc also plays an important role in immune function. Lower serum levels of zinc have been associated with disturbances in fatty acid metabolism and in serum lipid levels, which might affect brain function and vascular health. Lower zinc levels have also been associated cardiovascular disease, a common comorbidity of major depressive disorder (MDD), the authors note.
The investigators point out limitations of their study. The quality and risk of bias "were uneven among studies included in this meta-analysis," they write.
Not all studies reported demographic data "sufficiently to be included in investigations of heterogeneity, the use of antidepressants and other concomitant medications were not consistently reported, and data on diet and alcohol use were often not reported," the authors write.
Limitations notwithstanding, the authors conclude that their results suggest that depression is associated with reduced concentrations of zinc in peripheral blood.
"The findings suggest the need to further investigate potential roles of zinc in the pathophysiology of depression, the potential utility of zinc and related biomarkers in monitoring MDD and its clinical sequelae, and potential benefits of zinc supplementation in MDD patients," they conclude.
The study was supported by the Ontario Mental Health Foundation. Dr. Swardfager was supported by fellowships from the Heart and Stroke Foundation Center for Stroke Recovery and the Toronto Rehabilitation Institute. Dr. Swardfager and the other authors report no relevant financial relationships.
Welcome to my collection of health articles. Most of them contain little nuggets of health wisdom that we can easily apply to our daily lives. As you can gather, I've been consuming all sorts of supplements over the years, most of them from iherb. They deliver on time (DHL), and prices are good. If you're a first-time buyer, use my code 'pot089' to enjoy up to $10 off.
Showing posts with label zinc. Show all posts
Showing posts with label zinc. Show all posts
Wednesday, 8 January 2014
Tuesday, 19 February 2013
Zinc helpful within 24 hours of cold symptoms
When given within 24 hours of onset of symptoms, zinc reduces the duration and severity of the common cold in healthy people, according to the results of a Cochrane systematic review reported online February 16 in the Cochrane Database of Systematic Reviews.
Zinc supplements
"This review strengthens the evidence for zinc as a treatment for the common cold," said lead author Dr. Meenu Singh, from the Post Graduate Institute of Medical Education and Research in Chandigarh, India, in a news release. "However, at the moment, it is still difficult to make a general recommendation, because we do not know very much about the optimum dose, formulation or length of treatment."
To evaluate the effect of zinc on common cold symptoms, the reviewers searched CENTRAL (2010, Issue 2), which contains the Acute Respiratory Infections Group's Specialised Register, MEDLINE (1966 to May week 3, 2010), and EMBASE (1974 to June 2010). Inclusion criteria were randomized, double-blind, placebo-controlled trials in which zinc was used for 5 or more consecutive days to treat the common cold, or for 5 or months or longer for prevention. Data were independently extracted and trial quality examined by 2 reviewers.
The search identified 13 therapeutic trials enrolling a total of 966 participants, and 2 preventive trials enrolling a total of 394 participants, that met selection criteria. Zinc intake was associated with a significant decrease in duration of common cold symptoms (standardized mean difference [SMD], −0.97; 95% confidence interval [CI], −1.56 to −0.38; P = .001), as well as in severity (SMD, −0.39; 95% CI, −0.77 to −0.02; P = .04).
The proportion of participants symptomatic after 7 days of treatment was lower in the zinc group vs the control group (odds ratio [OR], 0.45; 95% CI, 0.2 - 1.00; P = .05). The zinc group also fared better than the control group in incidence rate ratio (IRR) for development of a cold (IRR, 0.64; 95% CI, 0.47 - 0.88; P = .006), school absence (P = .0003), and prescription of antibiotics (P < .00001).
However, overall adverse events were higher in the zinc group (OR, 1.59; 95% CI, 0.97 - 2.58; P = .06), as were bad taste (OR, 2.64; 95% CI, 1.91 - 3.64; P < .00001) and nausea (OR, 2.15; 95% CI, 1.44 - 3.23; P = .002).
"Our review only looked at zinc supplementation in healthy people," Dr. Singh said. "But it would be interesting to find out whether zinc supplementation could help asthmatics, whose asthma symptoms tend to get worse when they catch a cold."
Limitations of this review also include those inherent in the individual studies, such as placebo-blinding adequately described in only 6 trials, and allocation concealment unclear in 5 studies.
"[U]nlike trials relying on experimentally-induced rhinoviral colds, findings from large community-based trials will address issues relating to the diversity of and generalisability to the common cold," the review authors conclude. "In addition, given its toxicological profile, the potential for zinc to induce adverse effects at the doses participants are required to take also needs to be determined."
Source: http://www.medscape.com/viewarticle/737654
Zinc supplements
"This review strengthens the evidence for zinc as a treatment for the common cold," said lead author Dr. Meenu Singh, from the Post Graduate Institute of Medical Education and Research in Chandigarh, India, in a news release. "However, at the moment, it is still difficult to make a general recommendation, because we do not know very much about the optimum dose, formulation or length of treatment."
To evaluate the effect of zinc on common cold symptoms, the reviewers searched CENTRAL (2010, Issue 2), which contains the Acute Respiratory Infections Group's Specialised Register, MEDLINE (1966 to May week 3, 2010), and EMBASE (1974 to June 2010). Inclusion criteria were randomized, double-blind, placebo-controlled trials in which zinc was used for 5 or more consecutive days to treat the common cold, or for 5 or months or longer for prevention. Data were independently extracted and trial quality examined by 2 reviewers.
The search identified 13 therapeutic trials enrolling a total of 966 participants, and 2 preventive trials enrolling a total of 394 participants, that met selection criteria. Zinc intake was associated with a significant decrease in duration of common cold symptoms (standardized mean difference [SMD], −0.97; 95% confidence interval [CI], −1.56 to −0.38; P = .001), as well as in severity (SMD, −0.39; 95% CI, −0.77 to −0.02; P = .04).
The proportion of participants symptomatic after 7 days of treatment was lower in the zinc group vs the control group (odds ratio [OR], 0.45; 95% CI, 0.2 - 1.00; P = .05). The zinc group also fared better than the control group in incidence rate ratio (IRR) for development of a cold (IRR, 0.64; 95% CI, 0.47 - 0.88; P = .006), school absence (P = .0003), and prescription of antibiotics (P < .00001).
However, overall adverse events were higher in the zinc group (OR, 1.59; 95% CI, 0.97 - 2.58; P = .06), as were bad taste (OR, 2.64; 95% CI, 1.91 - 3.64; P < .00001) and nausea (OR, 2.15; 95% CI, 1.44 - 3.23; P = .002).
"Our review only looked at zinc supplementation in healthy people," Dr. Singh said. "But it would be interesting to find out whether zinc supplementation could help asthmatics, whose asthma symptoms tend to get worse when they catch a cold."
Limitations of this review also include those inherent in the individual studies, such as placebo-blinding adequately described in only 6 trials, and allocation concealment unclear in 5 studies.
"[U]nlike trials relying on experimentally-induced rhinoviral colds, findings from large community-based trials will address issues relating to the diversity of and generalisability to the common cold," the review authors conclude. "In addition, given its toxicological profile, the potential for zinc to induce adverse effects at the doses participants are required to take also needs to be determined."
Source: http://www.medscape.com/viewarticle/737654
Thursday, 24 May 2012
Zinc May Shorten Cold Symptoms in Adults, but Not Children
Oral zinc formulations may lessen the duration of cold symptoms in adults, but not in children, according to the findings of a meta-analysis.
Michelle Science, MD, from the Hospital for Sick Children, Toronto, Ontario, Canada, and colleagues published their findings online May 7 in the Canadian Medical Association Journal.
Of the 17 included trials, 8 trials involving patients with naturally acquired colds revealed that zinc reduced the duration of cold symptoms compared with placebo (mean difference, −1.65 days; 95% confidence interval [CI], −2.50 to −0.81 days), albeit with significant heterogeneity (I 2, 95%). Subgroup analysis revealed a statistically significant interaction between adults and children (P < .0001), as zinc reduced the duration of cold symptoms in adults (mean difference, −2.63; 95% CI, −3.69 to −1.58), but not in children (mean difference, −0.26; 95% CI, −0.78 to 0.25), with slightly lower heterogeneity (adults, I 2, 82%; children, I 2, 84%).
The authors noted that a previous meta-analysis reported the efficacy of zinc against common cold symptoms, but that significant heterogeneity was reported for the primary outcome. "The efficacy of zinc therefore remains uncertain, because it is unknown whether the variability among studies was due to methodologic diversity (i.e., risk of bias and therefore uncertainty in zinc's efficacy) or differences in study populations or interventions (i.e., zinc dose and formulation)," the authors write.
After a search of the MEDLINE, Embase, Cochrane, CINAHL, and AMED databases, the authors included randomized controlled trials that evaluated the efficacy of oral zinc as a single agent against placebo or no treatment with no restrictions placed on participant age, language, or year of publication. The authors excluded trials that evaluated intranasally administered zinc or orally administered zinc in combination with other modalities.
Additional subgroup analysis revealed a significant interaction for zinc formulation (P = .003), as zinc acetate (mean difference, −2.67; 95% CI, −3.96 to −1.38), but not zinc gluconate (mean difference, −1.72; 95% CI, −3.89 to 0.44) or zinc sulfate (mean difference, −0.31; 95% CI, −0.89 to 0.28), reduced the duration of symptoms compared with placebo. Regarding adverse events, only bad taste (8 trials; risk ratio [RR], 1.65; 95% CI, 1.27 - 2.16) and nausea (9 trials; RR, 1.64; 95% CI, 1.19 - 2.27) were more frequently observed in patients treated with zinc.
The limitations of the study included the large level of unexplained heterogeneity, the potentially ineffective blinding related to the taste of the placebo, the funding of all included studies by industry, and the performance of most studies in developed countries.
The authors indicated that uncertainty remains regarding the efficacy of zinc against common cold symptoms. "Although oral zinc treatment may attenuate the symptoms of the common cold, large high-quality trials enrolling adults and children are needed," the authors write. "Until further evidence becomes available, there is only a weak rationale for physicians to recommend zinc for the treatment of the common cold."
Source: http://www.medscape.com/viewarticle/763394?sssdmh=dm1.782072&src=nldne
Michelle Science, MD, from the Hospital for Sick Children, Toronto, Ontario, Canada, and colleagues published their findings online May 7 in the Canadian Medical Association Journal.
Of the 17 included trials, 8 trials involving patients with naturally acquired colds revealed that zinc reduced the duration of cold symptoms compared with placebo (mean difference, −1.65 days; 95% confidence interval [CI], −2.50 to −0.81 days), albeit with significant heterogeneity (I 2, 95%). Subgroup analysis revealed a statistically significant interaction between adults and children (P < .0001), as zinc reduced the duration of cold symptoms in adults (mean difference, −2.63; 95% CI, −3.69 to −1.58), but not in children (mean difference, −0.26; 95% CI, −0.78 to 0.25), with slightly lower heterogeneity (adults, I 2, 82%; children, I 2, 84%).
The authors noted that a previous meta-analysis reported the efficacy of zinc against common cold symptoms, but that significant heterogeneity was reported for the primary outcome. "The efficacy of zinc therefore remains uncertain, because it is unknown whether the variability among studies was due to methodologic diversity (i.e., risk of bias and therefore uncertainty in zinc's efficacy) or differences in study populations or interventions (i.e., zinc dose and formulation)," the authors write.
After a search of the MEDLINE, Embase, Cochrane, CINAHL, and AMED databases, the authors included randomized controlled trials that evaluated the efficacy of oral zinc as a single agent against placebo or no treatment with no restrictions placed on participant age, language, or year of publication. The authors excluded trials that evaluated intranasally administered zinc or orally administered zinc in combination with other modalities.
Additional subgroup analysis revealed a significant interaction for zinc formulation (P = .003), as zinc acetate (mean difference, −2.67; 95% CI, −3.96 to −1.38), but not zinc gluconate (mean difference, −1.72; 95% CI, −3.89 to 0.44) or zinc sulfate (mean difference, −0.31; 95% CI, −0.89 to 0.28), reduced the duration of symptoms compared with placebo. Regarding adverse events, only bad taste (8 trials; risk ratio [RR], 1.65; 95% CI, 1.27 - 2.16) and nausea (9 trials; RR, 1.64; 95% CI, 1.19 - 2.27) were more frequently observed in patients treated with zinc.
The limitations of the study included the large level of unexplained heterogeneity, the potentially ineffective blinding related to the taste of the placebo, the funding of all included studies by industry, and the performance of most studies in developed countries.
The authors indicated that uncertainty remains regarding the efficacy of zinc against common cold symptoms. "Although oral zinc treatment may attenuate the symptoms of the common cold, large high-quality trials enrolling adults and children are needed," the authors write. "Until further evidence becomes available, there is only a weak rationale for physicians to recommend zinc for the treatment of the common cold."
Source: http://www.medscape.com/viewarticle/763394?sssdmh=dm1.782072&src=nldne
Monday, 5 March 2012
Zinc decreases mortality in children with pneumonia
In a study conducted in Africa, children aged 6 to 59 months who had severe pneumonia had reduced mortality when receiving zinc in addition to standard antibiotics, a new study has found. In addition, the reduction in mortality was greater among HIV-infected than non-HIV-infected children.
Maheswari G. Srinivasan, from the Department of Pediatrics and Child Health at the School of Medicine, Makerere University College of Health Sciences, Kampala, Uganda, and colleagues reported the findings in an article published online February 8 in BMC Medicine.
"Given these results, zinc could be considered for use as adjunct therapy for severe pneumonia, especially among Highly Active Antiretroviral Therapy naïve HIV infected children in our environment," the authors conclude.
According to the researchers, acute respiratory tract infections is the most common cause of morbidity and mortality in children younger than 5 years of age, and the "burden of acute lower respiratory tract infections is 2 to 10 times more common in developing than in developed countries."
The results with zinc supplementation in this setting have been mixed. "One randomized controlled study from Bangladesh showed that zinc adjunct therapy accelerated recovery of children with severe pneumonia," the authors note, "but other studies have shown no effect," and "no studies have assessed the impact of zinc adjunct therapy on case fatality of children with pneumonia."
To evaluate this issue, the researchers randomly assigned children aged 6 to 59 months who had severe pneumonia to receive either zinc once daily for 7 days (n = 176; 20 mg for children aged 12 months or older and 10 mg for younger children) or a placebo once daily for 7 days (n = 176).
Children also received standard antibiotics for severe pneumonia and were assessed every 6 hours for oxygen saturation, respiratory rate, and temperature.
Among the children receiving zinc, 7 (4.0%) died compared with 21 patients (11.9%) in the placebo group. This represented nearly a 70% reduction in mortality risk in favor of zinc supplementation (relative risk [RR] reduction, 0.67; 95% confidence interval [CI], 0.24 - 0.85).
The greatest risk reduction was seen in HIV-infected children. Among HIV-infected children, case fatality was 7 of 27 children in the placebo group vs 0 of 28 children in the zinc group (RR, 0.1; 95% CI, 0.0 - 1.0).
In contrast, in HIV-uninfected children, no difference in case fatality was observed with zinc vs placebo: case fatality was 7/127 (5.5%) with placebo vs 5/129 (3.9%) among HIV-uninfected children receiving zinc (RR, 0.7; 95% CI, 0.2 - 2.2).
Maheswari G. Srinivasan, from the Department of Pediatrics and Child Health at the School of Medicine, Makerere University College of Health Sciences, Kampala, Uganda, and colleagues reported the findings in an article published online February 8 in BMC Medicine.
"Given these results, zinc could be considered for use as adjunct therapy for severe pneumonia, especially among Highly Active Antiretroviral Therapy naïve HIV infected children in our environment," the authors conclude.
According to the researchers, acute respiratory tract infections is the most common cause of morbidity and mortality in children younger than 5 years of age, and the "burden of acute lower respiratory tract infections is 2 to 10 times more common in developing than in developed countries."
The results with zinc supplementation in this setting have been mixed. "One randomized controlled study from Bangladesh showed that zinc adjunct therapy accelerated recovery of children with severe pneumonia," the authors note, "but other studies have shown no effect," and "no studies have assessed the impact of zinc adjunct therapy on case fatality of children with pneumonia."
To evaluate this issue, the researchers randomly assigned children aged 6 to 59 months who had severe pneumonia to receive either zinc once daily for 7 days (n = 176; 20 mg for children aged 12 months or older and 10 mg for younger children) or a placebo once daily for 7 days (n = 176).
Children also received standard antibiotics for severe pneumonia and were assessed every 6 hours for oxygen saturation, respiratory rate, and temperature.
Among the children receiving zinc, 7 (4.0%) died compared with 21 patients (11.9%) in the placebo group. This represented nearly a 70% reduction in mortality risk in favor of zinc supplementation (relative risk [RR] reduction, 0.67; 95% confidence interval [CI], 0.24 - 0.85).
The greatest risk reduction was seen in HIV-infected children. Among HIV-infected children, case fatality was 7 of 27 children in the placebo group vs 0 of 28 children in the zinc group (RR, 0.1; 95% CI, 0.0 - 1.0).
In contrast, in HIV-uninfected children, no difference in case fatality was observed with zinc vs placebo: case fatality was 7/127 (5.5%) with placebo vs 5/129 (3.9%) among HIV-uninfected children receiving zinc (RR, 0.7; 95% CI, 0.2 - 2.2).
According to the researchers, the excess risk with placebo was substantially greater among HIV-positive children than in HIV-negative children (absolute risk reduction, 26/100 children vs 2/100 children, respectively; P = .006).
They estimated that 13 patients needed to be treated to avert 1 death, and that children who received the placebo were 3 times more likely to die compared with those who received zinc.
"There are two key findings in this study: overall, zinc supplementation in these children significantly decreased case fatality, but did not reduce the time to normalization of the parameters for disease severity," the authors conclude.
According to the researchers, zinc supplementation might increase the immune response by boosting phagocytosis and averting apoptosis of T lymphocytes in HIV-infected patients.
They add that zinc deficiency (present in from 20% to 69% of children in this setting) "compromises immunity through a number of mechanisms, such as T cell dysfunction and dysregulation of intracellular killing."
They estimated that 13 patients needed to be treated to avert 1 death, and that children who received the placebo were 3 times more likely to die compared with those who received zinc.
"There are two key findings in this study: overall, zinc supplementation in these children significantly decreased case fatality, but did not reduce the time to normalization of the parameters for disease severity," the authors conclude.
According to the researchers, zinc supplementation might increase the immune response by boosting phagocytosis and averting apoptosis of T lymphocytes in HIV-infected patients.
They add that zinc deficiency (present in from 20% to 69% of children in this setting) "compromises immunity through a number of mechanisms, such as T cell dysfunction and dysregulation of intracellular killing."
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