title: Camellia sinensis in asymptomatic hyperuricemia: A meta-analysis of tea or tea extract effects on uric acid levels.
abstract: Flavanols of Camellia sinensis exhibit uric acid (UA) lowering effect, through the modulation of both xanthine oxidase and urate excretion. In order to investigate the potential benefit of Camellia Sinenis products in asymptomatic hyperuricemia, a meta-analysis of long-term Randomized Controlled Trials (RCT) with tea or tea extract has been conducted. From 20 human intervention studies selected only 5 RCT (13 interventions) were suitable for meta-analysis (n = 472). The current "normal" range set for hyperuricemia fails to identify patients with potential metabolic disorders. Therefore on the basis of the literature data, we fixed cut-off limits for UA baseline levels of 4.5 mg/dl for women, 6.1 mg/dl for men, and 5.5 mg/dl for studies involving mixed populations. Statistically significant effects were not found, but subgroup analysis revealed that the Pooled Estimate effect was different in subjects with baseline levels under [MD (95% CI): 0.1078 (-0.0528 to 0.2684)] and over the cut-off [MD (95% CI): -0.0239 (0.3311 to 0.2833)]. However, due to the low number of RCT and to the lack of data on bioavailability, it is difficult to draw any firm conclusion and more studies are needed to establish if tea flavanols could be useful in asymptomatic hyperuricemia treatment.
authors: a Department of Physiology and Pharmacology "V. Erspamer," "Sapienza" University of Rome , Rome , Italy.
authors: Ilaria
authors: I
authors: Peluso
authors: a Department of Physiology and Pharmacology "V. Erspamer," "Sapienza" University of Rome , Rome , Italy.
authors: Alessia
authors: A
authors: Teichner
authors: a Department of Physiology and Pharmacology "V. Erspamer," "Sapienza" University of Rome , Rome , Italy.
authors: Husseen
authors: H
authors: Manafikhi
authors: a Department of Physiology and Pharmacology "V. Erspamer," "Sapienza" University of Rome , Rome , Italy.
authors: Maura
authors: M
authors: Palmery
mesh_terms: D000975:Antioxidants / Q000009:adverse effects / Q000627:therapeutic use; D058070:Asymptomatic Diseases; D028241:Camellia sinensis / Q000737:chemistry* / Q000382:microbiology; D002318:Cardiovascular Diseases / Q000097:blood / Q000178:diet therapy / Q000503:physiopathology; D019587:Dietary Supplements / Q000009:adverse effects; D019317:Evidence-Based Medicine; D005285:Fermentation; D005511:Food Handling; D006801:Humans; D033461:Hyperuricemia / Q000209:etiology / Q000517:prevention & control*; D009765:Obesity / Q000097:blood / Q000178:diet therapy / Q000503:physiopathology; D018384:Oxidative Stress; D010936:Plant Extracts / Q000009:adverse effects / Q000627:therapeutic use*; D018515:Plant Leaves / Q000737:chemistry / Q000382:microbiology; D016032:Randomized Controlled Trials as Topic; D015203:Reproducibility of Results; D012907:Smoking / Q000009:adverse effects / Q000097:blood; D013662:Tea / Q000009:adverse effects / Q000737:chemistry / Q000382:microbiology; D014527:Uric Acid / Q000037:antagonists & inhibitors / Q000097:blood
chemical_list: D000975:Antioxidants; D010936:Plant Extracts; D013662:Tea; D014527:Uric Acid
keywords: Long-term intervention; meta-analysis; urate transport; uric acid; xanthine oxidase