Perhaps you have heard of a zinc tally test: a sip of a weak zinc solution, then a question about how it tastes. It is quick and simple, which is part of its appeal. Here is how it works, what it can and can't tell you, and what to do if you are worried your zinc is low.
What is the zinc tally test and how does it work?
Zinc supports your immune system, your skin, growth in childhood and pregnancy, and your senses of taste and smell. Your body can't make it, so it has to come from food. Healthdirect — Zinc deficiency
Low zinc has been linked with a duller sense of taste, and the zinc taste test builds on that idea: the less you can taste, the lower your zinc is assumed to be. It is commonly used by Australian naturopaths. Gruner and Arthur, systematic review
You hold a small amount of a weak zinc sulfate solution in your mouth for about ten seconds, then describe what you notice. Your answer is placed in one of four grades:
- no taste at all, as if it were water
- nothing at first, then a faint dry, mineral, furry or sweet taste after a few seconds
- a definite taste straight away that grows stronger
- a strong, unpleasant taste immediately
Zdilla and colleagues, test protocol
Why isn't it a diagnostic test?
A taste is a personal impression, not a measurement. An Australian systematic review found only three studies that compared the taste test with another zinc test, and their results were mixed. The authors concluded that the taste test does not reliably assess mildly low zinc. Gruner and Arthur, systematic review
The same review noted a few other problems:
- low zinc can dull taste, but it does not explain every case of reduced taste
- many other things change how something tastes
- the way the test is done varies a lot from its original design
Gruner and Arthur, systematic review
Smell is a good example. Taste and smell are closely connected, and smell can be affected by colds and other respiratory infections, a head injury or some medicines. Healthdirect — Anosmia
So a taste test result can start a conversation, but it can't confirm or rule out low zinc on its own.
What does a blood test add?
If your doctor thinks your zinc may be low, they may refer you for a blood test. It measures zinc directly, instead of relying on how something tastes. Healthdirect — Zinc deficiency
A blood test has limits too. It is not very reliable when a deficiency is mild. Healthdirect — Zinc deficiency Only about 1% of your body's zinc is in your blood plasma. That level is tightly controlled, so a mild deficiency often doesn't change it, while stress, injury or infection can lower it. NHMRC — Nutrient Reference Values: Zinc
That makes a blood result one useful piece of information rather than the whole answer. If your doctor does recommend a zinc supplement, they may organise a follow-up blood test. Please don't start one without talking to your doctor or pharmacist first: too much zinc can cause vomiting, diarrhoea and headaches, and can affect how well you absorb copper. Healthdirect — Foods high in zinc
Which foods contain zinc?
Most people get enough zinc from a balanced diet that includes some animal foods and a good range of plant foods. Good sources include:
- oysters, the richest source, and other seafood such as crab and sardines
- red meat and chicken
- eggs, milk and cheese
- nuts and seeds, including pumpkin seeds (pepitas)
- wholegrains such as oats
Healthdirect — Foods high in zinc
Your body absorbs zinc more easily from animal foods than from plant foods, so if you follow a plant-based diet, you may be more likely to run low. Healthdirect — Zinc deficiency Your needs may be higher if grains and legumes are your main staples. NHMRC — Nutrient Reference Values: Zinc
Low zinc is also more likely after an illness or surgery, during pregnancy, after 65, or with conditions that affect your digestive tract. Healthdirect — Foods high in zinc
When to see your GP
See your GP if you think you or your child may have low zinc, or if you are planning a pregnancy. Signs worth mentioning include:
- a rash that looks like eczema and doesn't settle with the usual treatment
- cuts and wounds that take longer than usual to get better
- hair loss
- getting infections more often
- slow growth or delayed puberty in a child
Healthdirect — Zinc deficiency
See your doctor, too, if your sense of smell hasn't come back after a few weeks. Healthdirect — Anosmia If a rash is your main concern, our eczema guide has questions to take along.
What can we talk about at Melbourne Wellness?
An initial naturopathy consultation includes a detailed health history and a look at what you eat day to day. We can help you see where zinc-containing foods could fit into meals you already enjoy, and note anything worth raising with your GP.
Questions you might bring along:
- Could my symptoms have a cause other than zinc?
- Would a blood test help in my case, and how should I prepare for it?
- Do any of my medicines or supplements matter here?
- Am I getting enough zinc if I eat mostly plants?
For a similar conversation about another nutrient, see our post on vitamin D and questions about testing.
