Taste acuity in response to zinc supplementation in older Europeans

Northern Ireland Centre for Food and Health, University of Ulster, Coleraine BT52 1SA, UK.
British Journal Of Nutrition (Impact Factor: 3.34). 02/2008; 99(1):129-36. DOI: 10.1017/S0007114507781485
Source: PubMed

ABSTRACT Taste acuity declines with age and may be dependent upon Zn status. The aim of the present double-blind, randomised controlled intervention trial has been to determine taste acuity in response to Zn supplementation (placebo, or 15 or 30 mg Zn/d). Healthy older European adults aged 70-87 years were recruited within Italy (Rome) (n 108) and France (Grenoble) (n 91) to the European Commission-funded Zenith project. A signal detection theory approach was adopted for taste assessment. The data were converted to R indices and analysed by repeated-measures ANOVA controlling for baseline taste acuity as well as serum and erythrocyte Zn. Serum Zn increased post-intervention, indicating compliance with the intervention. Results differed across geographical region. Salt taste acuity was greater in response to Zn (30 mg) than placebo post-intervention among those recruited in Grenoble. There was no apparent change in acuity for sweet, sour or bitter taste in response to Zn. Supplemented Zn may have potential to enhance salt taste acuity in those over the age of 70 years. Further research is required to determine if enhanced salt taste acuity is reflected in the eating experiences of older individuals.


Available from: Heather Parr, Apr 08, 2014
  • [Show abstract] [Hide abstract]
    ABSTRACT: Background The sense of taste is very much essential to the overall health of the individual. It is a necessary component to enjoying one’s food, which in turn provides nutrition to an individual. Any disturbance in taste perception can hamper the quality of life in such patients by influencing their appetite, body weight and psychological well-being. Taste disorders have been treated using different modalities of treatment and there is no consensus for the best intervention. Hence this Cochrane systematic review was undertaken. Objectives To assess the effects of interventions for the management of patients with taste disturbances. Search methods We searched the Cochrane Oral Health Group Trials Register (to 5 March 2014), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 1, 2014), MEDLINE via OVID (1948 to 5 March 2014), EMBASE via OVID (1980 to 5 March 2014), CINAHL via EBSCO (1980 to 5 March 2014) and AMED via OVID (1985 to 5 March 2014). We also searched the relevant clinical trial registries and conference proceedings fromthe International Association of Dental Research/American Association of Dental Research (to 5 March 2014), Association for Research in Otolaryngology (to 5 March 2014), the US National Institutes of Health Trials Register (to 5 March 2014), metaRegister of Controlled Trials (mRCT) (to 5March 2014), World Health Organization’s International Clinical Trials Registry Platform (WHO ICTRP) (to 5 March 2014) and International Federation of Pharmaceutical Manufacturers and Associations (IFPMA) Clinical Trials Portal (to 5 March 2014). Selection criteria We included all randomised controlled trials (RCTs) comparing any pharmacological agent with a control intervention or any nonpharmacological agent with a control intervention. We also included cross-over trials in the review. Data collection and analysis Two authors independently, and in duplicate, assessed the quality of trials and extracted data. Wherever possible, we contacted study authors for additional information. We collected adverse events information from the trials. Main results We included nine trials (seven parallel and two cross-over RCTs) with 566 participants.We assessed three trials (33.3%) as having a low risk of bias, four trials (44.5%) at high risk of bias and two trials (22.2%) as having an unclear risk of bias. We only included studies on taste disorders in this review that were either idiopathic, or resulting from zinc deficiency or chronic renal failure. Of these, eight trials with 529 people compared zinc supplements to placebo for patients with taste disorders. The participants in two trials were children and adolescents with respective mean ages of 10 and 11.2 years and the other six trials had adult participants. Out of these eight, two trials assessed the patient reported outcome for improvement in taste acuity using zinc supplements (RR 1.45, 95% CI 1.0 to 2.1; very low quality evidence). We included three trials in the meta-analysis for overall taste improvement (effect size 0.44, 95% CI 0.23 to 0.65; moderate quality evidence). Two other trials described the results as taste acuity improvement and we conducted subgroup analyses due to clinical heterogeneity.One trial described the results as taste recognition improvement for each taste sensation and we analysed this separately.We also analysed one cross-over trial separately using the first half of the results. None of the zinc trials tested taste discrimination. Only one trial tested taste discrimination using acupuncture (effect size 2.80, 95% CI -1.18 to 6.78; low quality evidence). Out of the eight trials using zinc supplementation, four reported adverse events like eczema, nausea, abdominal pain, diarrhoea, constipation, decrease in blood iron, increase in blood alkaline phosphatase, and minor increase in blood triglycerides. No adverse events were reported in the acupuncture trial. None of the included trials could be included in the meta-analysis for health-related quality of life in taste disorder patients. Authors’ conclusions We found very low quality evidence that was insufficient to conclude on the role of zinc supplements to improve taste perception by patients, however we found moderate quality evidence that zinc supplements improve overall taste improvement in patients with zinc deficiency/idiopathic taste disorders. We also found low quality evidence that zinc supplements improve taste acuity in zinc deficient/ idiopathic taste disorders and very low quality evidence for taste recognition improvement in children with taste disorders secondary to chronic renal failure. We did not find any evidence to conclude the role of zinc supplements for improving taste discrimination, or any evidence addressing health-related quality of life due to taste disorders. We found low quality evidence that is not sufficient to conclude on the role of acupuncture for improving taste discrimination in cases of idiopathic dysgeusia (distortion of taste) and hypogeusia (reduced ability to taste).We were unable to draw any conclusions regarding the superiority of zinc supplements or acupuncture as none of the trials compared these interventions.
    Cochrane database of systematic reviews (Online) 11/2014; November(11). DOI:10.1002/14651858.CD010470.pub2 · 5.94 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: This study investigated the relationship between taste sensitivity, the frequency and the preference for eating foods rich in zinc, dietary habits, and restrained eating among Japanese female undergraduate students. Forty-three subjects be-tween the ages of 20 and 22 participated in this study. After a taste-sensitivity test for sweetness and saltiness the stu-dents completed a food list indicating the intake frequency and preference of foods rich in zinc and their eating habits. The students were divided into four groups: high salt-taste sensitivity (SA-HG), low salt-taste sensitivity (SA-LG), high sweet-taste sensitivity (SW-HG), and low sweet-taste sensitivity (SW-LG). Individuals in the SA-HG group ate more foods rich in zinc and were more concerned with their health than those in the SA-LG group. Further, the SW-LG group ate more convenience foods than the SW-HG group. High salt-taste sensitivity could be predicted by eating more but less preference of foods rich in zinc, less snacking, and greater regularity of meals. On the other hand there is a signifi-cant positive relationship between the frequencies of eating and preference for foods rich in zinc. This means the results were inconsistent, further research is needed to clarify this point.
    Food and Nutrition Sciences 01/2012; 03(03). DOI:10.4236/fns.2012.33044
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Alterations in trace element homeostasis could be involved in the pathology of dementia, and in particular of Alzheimer's disease (AD). Zinc is a structural or functional component of many proteins, being involved in numerous and relevant physiological functions. Zinc homeostasis is affected in the elderly, and current evidence points to alterations in the cellular and systemic distribution of zinc in AD. Although the association of zinc and other metals with AD pathology remains unclear, therapeutic approaches designed to restore trace element homeostasis are being tested in clinical trials. Not only could zinc supplementation potentially benefit individuals with AD, but zinc supplementation also improves glycemic control in the elderly suffering from diabetes mellitus. However, the findings that select genetic polymorphisms may alter an individual's zinc intake requirements should be taken into consideration when planning zinc supplementation. This review will focus on current knowledge regarding pathological and protective mechanisms involving brain zinc in AD to highlight areas where future research may enable development of new and improved therapies.
    Genes & Nutrition 01/2014; 9(1):379. DOI:10.1007/s12263-013-0379-x · 3.42 Impact Factor