Nutrition Reviews

Chew, Han Shi Jocelyn; Soong, Rou Yi; Teo, Yu Qing Jolene; Flølo, Tone Nygaard; Chong, Bryan; Yong, Cai Ling; Ang, Shi Han; Ho, Yishen; Chew, Nicholas W S; So, Jimmy Bok Yan; Shabbir, Asim

doi: 10.1093/nutrit/nuad163pmid: 38213191

ContextPolyphenols are plant-based compounds with potential anti-inflammatory, antioxidant, and anti-obesogenic properties. However, their effects on health outcomes remain unclear.ObjectiveTo evaluate the effects of polyphenols on anthropometric and cardiometabolic markers.Data SourcesSix electronic databases—namely, EMBASE, CINAHL, PubMed, Scopus, The Cochrane Library (reviews only), and Web of Science—were searched for relevant systematic reviews with meta-analyses (SRMAs).Data ExtractionThree reviewers performed the data extraction via a data-extraction Microsoft Excel spreadsheet.Data AnalysisAn umbrella review and meta-analysis of existing SRMAs was conducted. Eighteen SRMAs published from 2015 to 2023, representing 445 primary studies and 838 unique effect sizes, were identified. Meta-analyses were conducted using random-effects models with general inverse variance. Polyphenol-containing foods were found to significantly improve weight (-0.36 kg; 95% confidence interval [CI]: −0.62, 0.77 kg; P < 0.01, I2 = 64.9%), body mass index (−0.25 kg/m2; 95% CI: −0.34, −0.17 kg/m2; P < 0.001, I2 = 82.4%), waist circumference (−0.74 cm; 95% CI: −1.34, −0.15 cm; P < 0.01, I2 = 99.3%), low-density-lipoprotein cholesterol (−1.75 mg/dL; 95% CI: −2.56, −0.94; P < 0.001, I2 = 98.6%), total cholesterol (−1.23 mg/dL; 95% CI: −2.00, −0.46; P = 0.002, I2 = 94.6%), systolic blood pressure (−1.77 mmHg; 95% CI: −1.77, −0.93 mmHg; P < 0.001, I2 = 72.4%), diastolic blood pressure (−1.45 mmHg; 95% CI: −2.09, −0.80 mmHg; P < 0.001, I2 = 61.0%), fat percentage (−0.70%; 95% CI: −1.03, −0.36%; P < 0.001, I2 = 52.6%), fasting blood glucose (−0.18 mg/dL; 95% CI: −0.35, −0.01 mg/dL; P = 0.04, I2 = 62.0%), and C-reactive protein (CRP; including high-sensitivity-CRP [hs-CRP]) (−0.2972 mg/dL; 95% CI: −0.52, −0.08 mg/dL; P = 0.01, I2 = 87.9%). No significant changes were found for high-density-lipoprotein cholesterol (−0.12 mg/dL; 95% CI: −1.44, 0.69; P = 0.67, I2 = 89.4%) and triglycerides (−1.29 mg/dL; 95% CI: −2.74, 0.16; P = 0.08, I2 = 85.4%). Between-study heterogeneity could be explained by polyphenol subclass differences.ConclusionThe findings of this umbrella review support the beneficial effects of polyphenols on anthropometric and metabolic markers, but discretion is warranted to determine the clinical significance of the magnitude of the biomarker improvements.Systematic Review RegistrationInternational Prospective Register of Systematic Reviews no. CRD42023420206.

Golder, Janet E; Bauer, Judith D; Barker, Lisa A; Lemoh, Christopher N; Gibson, Simone J; Davidson, Zoe E

doi: 10.1093/nutrit/nuad157pmid: 38219216

BackgroundAssessment for vitamin C deficiency (VCD) is rarely undertaken in an acute hospital setting in high-income countries. However, with growing interest in VCD in community settings, there is emerging evidence investigating the prevalence and impact of VCD during hospitalization.ObjectivesIn this scoping review, the prevalence of VCD in adult hospitalized patients is explored, patient characteristics are described, and risk factors and clinical outcomes associated with VCD are identified.MethodsA systematic scoping review was conducted in accordance with the PRISMA-ScR framework. The Ovid MEDLINE, Ovid Embase, Scopus, CINAHL Plus, Allied and Complementary Medicine Database, and the Cochrane Library databases were searched for interventional, comparative, and case-series studies that met eligibility criteria, including adult hospital inpatients in high-income countries, as defined by the Organization for Economic Co-operation and Development, that reported VCD prevalence using World Health Organization reference standards. These standards define VCD deficiency as plasma or serum vitamin C level <11.4 µmol/L, wholeblood level <17 µmol/L, or leukocytes <57 nmol/108 cells.ResultsTwenty-three articles were included, representing 22 studies. The cumulative prevalence of VCD was 27.7% (n = 2494; 95% confidence interval [CI], 21.3-34.0). High prevalence of VCD was observed in patients with severe acute illness and poor nutritional status. Scurvy was present in 48% to 62% of patients with VCD assessed in 2 studies (n = 71). Being retired (P = 0.015) and using excessive amounts of alcohol and tobacco (P = 0.0003) were independent risk factors for VCD (n = 184). Age was not conclusively associated with VCD (n = 631). Two studies examined nutrition associations (n = 309); results were inconsistent. Clinical outcomes for VCD included increased risk of frailty (adjusted odds ratio, 4.3; 95%CI, 1.33–13.86; P = 0.015) and cognitive impairment (adjusted odds ratio, 2.93; 95%CI, 1.05–8.19, P = 0.031) (n = 160).ConclusionsVCD is a nutritional challenge facing the healthcare systems of high-income countries. Research focused on early identification and treatment of patients with VCD is warranted.Systematic Review RegistrationOpen Science Framework (https://doi.org/10.17605/OSF.IO/AJGHX).