The sense of taste is essential to the health and psychological well-being of an individual. Taste disorders can range from lack of taste, to distortion of taste, to reduced ability to taste. Any disorder in taste perception can lead to conditions like malnutrition and consumption of poisonous food substances. The cause may be due to disease, drugs, radiation treatment or aging, or it may be from unknown causes. Various treatment methods have been proposed, including the use of zinc supplements, pilocarpine, alpha lipoic acid, transcranial magnetic stimulation, ginkgo bilboa and acupuncture. The review found that zinc supplements may have some benefit, but the evidence was insufficient to draw firm conclusions.
What was the research?
A systematic review of the evidence to find out the best method for the management of taste disorders.
Who conducted the research
The research was conducted by a team led by Sumanth Kumbargere Nagraj, on behalf of the Cochrane Oral Health Group. Shetty Naresh, Kandula Srinivas, P Renjith George, Ashish Shrestha, David Levenson and Debra M Ferraiolo were also on the team.
What evidence was included in the review?
Data was extracted from nine randomised controlled trials (RCTs). A total of 566 people participated. Eight trials looked at zinc supplements and one trial assessed the effect of acupuncture.
What did the evidence say?
There was some evidence that zinc supplements could improve overall taste perception in people with idiopathic taste disorders (ie taste disorders with an unknown origin) or taste disorders resulting from a zinc deficiency. However, the evidence was not high quality. The trial using acupuncture showed some benefit for taste discrimination, however the results were based on one small trial with a low number of participants.
How good was the evidence?
The quality of evidence found in this review was of very low to moderate quality due to issues with the way in which some of the included studies were conducted.
What are the implications for clinicians and the general public?
There is insufficient evidence to conclude that either zinc supplements or acupuncture can improve the health-related quality of life in taste disorder patients, although there was some low or moderate quality evidence of benefit. More evidence is needed.
What should researchers look at in the future?
Further research should be undertaken in the management of taste disorders by conducting well planned RCTs with more clarity and uniformity in the variables. All the trials should evaluate improvement in taste acuity and taste discrimination; patient reported outcomes and objective testing should both be evaluated. Reports on clinical trials would be improved by following CONSORT group guidelines. Other than taste improvement, outcomes like health-related quality of life and improvement in nourishment should be considered in future trials.
Kumbargere Nagraj S, Naresh S, Srinivas K, Renjith George P, Shrestha A, Levenson D, Ferraiolo DM. Interventions for the management of taste disturbances. Cochrane Database of Systematic Reviews 2014, Issue 11. Art. No.: CD010470. DOI: 10.1002/14651858.CD010470.pub2.