Last week I received an email from a local spa. I usually just delete this sort of thing without reading it but I decided to open it. Scrolling down, I saw them proudly offering zinc deficiency tests and asking us to “show our zinc face”. Apparently this $7 test diagnoses zinc deficiency through a simple taste test. If the substance tastes bitter then your zinc stores are adequate. If the substance is flavourless then you’re deficient in zinc. I had never heard of the zinc taste test before and it sounded a little suspicious to me. I did a little delving.
Of course google took me to a whole bunch of site of spas and naturopaths offering this fun easy zinc deficiency taste test. Searching a little more I found a study into the accuracy of the zinc taste test. According to the researchers, “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.” How does the zinc taste test work? Those who are deficient in zinc experience “diminished taste acuity”.
The problem with the test is primarily that there are other conditions, besides zinc deficiency, that can lead to diminished taste acuity. By accepting the results of the taste test, without confirming the diagnosis with their doctor, people may risk ignoring other underlying conditions and may unnecessarily self-medicate with zinc supplements.
While zinc deficiency is estimated to be quite common worldwide, about 30%, in “high-income” countries such as Canada and the US, estimates are between 3-11% of the population (1). Zinc is an important mineral for development, especially for sexual maturation, the immune system, and wound healing. However, extended, unnecessary or excessive zinc supplementation can increase the risk of deficiency of other minerals such as copper and can cause a whole host of other medical problems.
It concerns me that people may be taking this test, essentially self-diagnosing and self-treating. If you want to take the zinc taste test for fun at the spa, go for it. If the test indicates that you may be deficient in zinc, go see your doctor for confirmation and appropriate treatment options.