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Dietetics, Nutrition and Biological Sciences

Permanent URI for this collectionhttps://eresearch.qmu.ac.uk/handle/20.500.12289/23

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Start date: 2020Subject: search.filters.subject.Meta-analysis

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    Effect of N-Acetylcysteine on Positive and Negative Syndrome Scale associated with Schizophrenia: A Meta-Analysis
    (Mashhad University of Medical Sciences, 2020-10) Ghaderi, Amir; Bussu, Anna; Tsang, Catherine; Jafarnejad, Sadegh
    Background and objective: N-acetylcysteine (NAC), a precursor of L-cysteine with antioxidant, anti-inflammatory and neurotropic effects, is a promising agent in alleviating symptoms associated with schizophrenia. However, the role of NAC on parameters of Positive and Negative Syndrome Scale (PANSS) remain uncertain. This systematic review and meta-analysis explored the effect of NAC on parameters of PANSS in patients with chronic schizophrenia. Methods: We searchedPubmed/MEDLINE™, PsycNET™, PsycLIT™, Scopus™ and Google Scholar™ for studies on the effect of NAC on PANSS in patients with schizophrenia from inception to March 2019. We adopted medical and non-medical subjects headings (MeSH, non-MeSH) and several keywords, including “NAC”, “N-acetylcysteine”, “N-acetyl cysteine”, “Acetylcysteine”, “N-Acetyl-L-cysteine”, “schizophrenia”, “psychotic disorder”, “psychosis”, “schizoaffective” and “dementia praecox”. Results: We identified seven trials with274 patients meeting the inclusion criteria, with follow up between 8-52 weeks, and NAC supplementation between 1200-3600 mg/day. Significant improvements in PANSS were identified following NAC for total (SMD=-0.61, 95% CI = -0.91, -0.31 ; P<0.001), general (SMD = -0.58; 95% CI = -0.90, -0.26; P=0.0004); and negative (SMD = -0.56; 95% CI = -0.92, -0.21; P = 0.001) scores, respectively. No significant heterogeneity was found among studies. Significant reductions were observed following sub-group analysis in trials ≤ 24 weeks duration, with appreciable effect size for total (SMD= -0.83), general (SMD= -0.67) and negative (SMD=-1.09) scores. Conclusion: Supplementation of NAC was effective in alleviating PANSS symptoms associated with schizophrenia in trials ≤ 24 weeks duration. The use of NAC as an adjunct seems promising and further investigation is warranted to determine its precise role.
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    Potential blood pressure lowering effect of L-citrulline supplementation in at risk populations: a meta-analysis
    (Emerald, 2022-05-10) Jafarnejad, Sadegh; Tsang, Catherine; Amin, Negin
    Purpose This paper aims to investigate the effect of L-citrulline supplementation on blood pressure (BP) in middle-aged and elderly populations. Design/methodology/approach Three electronic databases, namely, Google Scholar, PubMed and Scopus, were searched from 1990 to November 2020. Random effects model analysis was applied for quantitative data synthesis, and 6 trials with 150 participants were identified and included in the analysis. Findings Results showed an overall non-significant effect of L-citrulline supplementation on both systolic BP (SBP) and diastolic BP (DBP) in middle-aged and elderly participants. However, stratified analysis indicated a significant reduction in SBP (SMD: −0.41, 95% CI: −0.84, 0.02; p = 0.06, heterogeneity p = 0.41; I2 = 10%) but not in DBP (SMD:−0.15, 95% CI: −0.57, 0.28; p = 0.51, heterogeneity p = 0.60; I2 = 0%), following longer-term (= 8 weeks) supplementation of L-citrulline. Additionally, higher doses of L-citrulline (= 6 grams) showed a marginally significant reduction in DBP (SMD: −0.38, 95% CI: −0.78, 0.02; p = 0.06, heterogeneity p = 0.50; I2 = 0%). Originality/value In conclusion, a higher dosage and longer duration of supplementation with L-citrulline may have potential BP lowering effects in populations at an increased risk of hypertension
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    Effect of Polyphenol Supplementation on Memory Functioning in Overweight and Obese Adults: A Systematic Review and Meta-Analysis
    (MDPI, 2024-02-06) Farag, Sara; Tsang, Catherine; Al-Dujaili, Emad A. S.; Murphy, Philip N.
    Negative health consequences of obesity include impaired neuronal functioning and cell death, thus bringing the risk of impaired cognitive functioning. Antioxidant properties of polyphenols offer a possible intervention for overweight people, but evidence for their effectiveness in supporting cognitive functioning is mixed. This review examined evidence from randomized controlled trials concerning the effect of polyphenols on tasks requiring either immediate or delayed retrieval of learned information, respectively, thus controlling for differences in cognitive processes and related neural substrates supporting respective task demands. Searches of the PubMed/Medline, PsycInfo, and Scopus databases identified 24 relevant primary studies with N = 2336 participants having a BMI ≥ 25.0 kg/m2. The participants’ mean age for the 24 studies exceeded 60 years. Respective meta-analyses produced a significant summary effect for immediate retrieval but not for delayed retrieval. The present findings support a potential positive effect of chronic supplementation with polyphenols, most notably flavonoids, on immediate retrieval in participants aged over 60 years with obesity being a risk factor for cognitive impairment. We recommend further investigation of this potential positive effect in participants with such risk factors. Future research on all populations should report the phenolic content of the supplementation administered and be specific regarding the cognitive processes tested.