Taste and smell losses in normal aging and disease

Objective.-To review the scientific literature on the alterations in the senses of taste and smell in the elderly, including causes, diagnosis, prognosis, and treatment. Data Sources.-Original reports and reviews obtained through MEDLINE searches from 1966 through June 1997 using the MeSH headings of '''taste,'' ''taste buds,'' ''qaste disorders,'' ''taste thresholds,'' ''smell,'' ''odors,'' ''aged,'' and ''aging.'' Articles frequently cited in reference lists were also included. Study Selection.-All articles were reviewed, tabulated, and summarized. Data Extraction.-Criteria for extraction included data quality and validity, statistical treatment of the data, venue of publication, and relevance to clinical care. Conclusion.-Losses of taste and smell are common in the elderly and result from normal aging, certain disease states (especially Alzheimer disease), medications, surgical interventions, and environmental exposure. Deficits in these chemical senses cannot only reduce the pleasure and comfort from food, but represent risk factors for nutritional and immune deficiencies as well as adherence to specific dietary regimens. Chemosensory decrements can lead to food poisoning or overexposure to environmentally hazardous chemicals that are otherwise detectable by taste and smell. Use of flavor-enhanced food can increase enjoyment of food and have a positive effect on food intake and immune status.