The Zinc Taste Test is a method commonly used by alternative health practitioners to test for zinc deficiency that is not accurate, reliable or valid.
The Zinc Taste Test involves taking a challenge solution of zinc sulfate in purified water at a concentration of 2.5 gm/10ml and holding it in the mouth for 10 seconds. An immediate strong metallic taste is claimed to indicate adequate levels. If the zinc is not tasted, then it is claimed there is a deficiency. A slightly low level is claimed to be indicated by a mildly unpleasant taste. Commercial varieties of the test are widely available to purchase (eg, at Amazon)
Research on the Zinc Taste Test (ZTT):
Cliff J. d C. Harvey and Ashley Greaves (2021) in the Journal of Holistic Performance reviewed the research and concluded that:
Zinc taste tests are commonly used by complementary and alternative practitioners, pharmacies and in medical practices and research to determine zinc status and deficiency. However, despite this common use, evidence for the reliability and accuracy of this test for determining zinc status is lacking.
It is the position of the Holistic Performance Institute that unless further research can demonstrate accuracy and reliability of zinc taste testing, the use of this test in clinical practice should be avoided due to the potential to misdiagnose zinc deficiency and the risk of zinc overload. (link)
A 2012 review of the research by Tini Gruner and Rachel Arthur in The Journal of Alternative and Complementary Medicine concluded that:
To date, there are no tests that are both sensitive and specific that accurately assess marginal zinc status in humans. The ZTT, albeit widely used, does not fill this void, and further research is needed.(link)
- it is common to see claims for the reliability of the zinc taste test on alternative health practitioners’ websites. They never cite references for that and the test is not reliable.
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