Quick answer
New Zealand soils are naturally low in selenium, but Medsafe reports no clear evidence of widespread deficiency, thanks partly to selenium-supplemented livestock feed and imported grains and legumes. Supplements sold in New Zealand must not exceed 150 micrograms of selenium per daily dose. Selenium has a narrow safety margin, so more is not automatically better.
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New Zealand soils are naturally low in selenium, a long-recognised agricultural and nutritional feature of the country.
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Medsafe reports no clear evidence this has caused widespread selenium deficiency disease in New Zealanders.
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Dietary supplements sold in New Zealand must not exceed 150 micrograms of selenium per daily dose, by regulation.
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Selenium has a narrower safety margin than many minerals, so more is not automatically better.
Why is selenium linked to New Zealand soils specifically?
Selenium content in food largely reflects the soil it was grown in, and New Zealand's naturally low soil selenium has been documented since the mid-twentieth century, initially because of its effects on livestock rather than people. Pastoral farming practice now commonly accounts for this with animal supplementation.
For humans, the picture is more reassuring. Medsafe has noted that with current selenium supplementation of animals and poultry, plus imported plant foods such as wheat and legumes that tend to carry more selenium, most New Zealanders' selenium intake sits at or around recommended levels.
How is selenium regulated in New Zealand supplements?
Selenium is one of the minerals specifically addressed in the Dietary Supplements Regulations 1985, which set a maximum daily dose for an adult of 150 micrograms in any product sold as a dietary supplement in New Zealand. This exists because selenium has a comparatively narrow gap between an intake that supports normal function and one that can cause toxicity.
Medsafe has previously noted that labels on selenium supplements commonly recommend a daily dose in the 50 to 200 microgram range, while the regulatory ceiling for New Zealand-manufactured dietary supplements remains 150 micrograms. Always check the label of any product you buy rather than assuming a particular dose.
What does excess selenium look like?
Selenium toxicity is uncommon at typical dietary or supplement intakes, but it can occur with sustained high intakes, particularly from supplements or concentrated selenium-rich foods such as Brazil nuts eaten in large quantities. Reported signs include a garlic-like odour on the breath, fatigue, gastrointestinal upset, brittle nails or nail changes, hair loss, and nerve-related symptoms in more severe cases.
If you are already eating a varied diet that includes some imported grains, legumes, meat or seafood, be cautious about stacking multiple selenium-containing products, since totals can add up without you realising it.
People also ask
Frequently asked questions
Does living in New Zealand mean you are likely to be selenium deficient?
Not necessarily. While New Zealand soils are naturally low in selenium, Medsafe has reported no clear evidence of widespread selenium deficiency in New Zealanders, partly due to selenium-supplemented livestock feed and imported plant foods. This guide is general information, not a diagnosis of your own status.
What is the maximum selenium dose allowed in a New Zealand supplement?
Under the Dietary Supplements Regulations 1985, a dietary supplement sold in New Zealand must not provide more than 150 micrograms of selenium per daily dose for an adult. Always check the actual label of the product you are considering.
Can you take selenium alongside other supplements?
You can, but selenium can appear in multiple products such as multivitamins, specific mineral supplements and some formulas marketed for antioxidant support. Add up your total intake across everything you take, and speak with a pharmacist if you are unsure.
Evidence and further reading
This guide provides general education, not diagnosis or individual medical advice. Follow product labels and speak with an appropriately qualified health professional when you are pregnant, nursing, taking medication or managing a health condition.
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