Did you know New Zealand soils are lacking in certain minerals? – by Brett Friedman

Did you know New Zealand soils are lacking in certain minerals? We look at conditions specific to New Zealand and how to make sure you are getting enough of these nutrients, written by Brett Friedman


From the dramatic high country of the South Island to the sub-tropical north, New Zealand boasts some of the most beautiful, lush and unique vegetation in the world. Our native trees, ferns, shrubs and diverse range of lush grasses have all adapted to the unique growing conditions.

While varying from region to region, poor-quality volcanic soils cover most of the country. New Zealand soils also tend to be naturally acidic due to the lack of natural lime and the acidifying effects of organic matter from the natural forests that cover much of the landscape.

Our relatively short farming history combined with good farming practices and an abundance of organic matter mean our soils are rich in organic material, however the reality is that they can also be lacking in certain important minerals. As a result, the produce that grows in these soils can also be deficient in these same nutrients.

What nutrients are we talking about here? Well while there is of course regional variation, various studies have shown New Zealand soils to be deficient in selenium, iodine, zinc, chromium and boron – all minerals essential for the functioning of the human body.

Besides soil quality, it is worth noting that changing eating habits – such as our increased consumption of highly processed, nutrient-low ‘convenience’ foods – are also impacting on nutrient intake.

So let’s take a closer look at some of these nutrients to find out why they are so important and what you can do to make sure you are getting enough of them.


It is well known that the concentration of selenium in New Zealand soils is low. It is a trace mineral and important antioxidant for the body. Antioxidants are molecules that support healthy cell function and metabolism. In addition to this basic function, selenium also supports healthy tissue elasticity, works together with vitamin E to help support healthy heart and liver function, supports thyroid hormone conversion and supports healthy immune function by assisting in antibody production.

Livestock and poultry feeds are supplemented with selenium and so if you’re eating meat from local commercially-farmed animals, then you should be getting enough of this mineral from these sources. Other important dietary sources include imported Brazil nuts, tuna, sunflower seeds, oysters, whole grain cereals and savoury yeast. Selenium supplements are also an excellent way to support your selenium levels.


This important mineral is involved in hundreds of different enzyme reactions in the body. It is also important for healthy immune support, cell growth and unction and insulin production. Zinc is found in highest amounts in foods such as seafood and red meat, so vegans and vegetarians are possibly most at risk of not obtaining enough of this mineral from their diets. Increased consumption of refined grains combined with excess calcium supplementation may also increase the requirement for zinc. Increasing your intake of animal proteins may boost your zinc levels, while zinc supplements are also a good way to achieve this.


Iodine is a mineral that is important for thyroid gland function where it is required for the synthesis of the thyroid hormones. These hormones stimulate the body’s basal metabolic rate, increase oxygen consumption and heat production, and influence the activity of most organs. Iodine is also important for supporting a healthy pregnancy. Iodine deficiency has become a global problem and in an attempt to remedy this, governments have introduced iodised salt into food legislation. However, many kiwis have opted to use natural rock salts and sea salt which have much lower levels of iodine.

The iodine content of food will vary depending on the region in which it is found, but the best food sources include seaweed (kelp) and marine fish. If you grow your own fruits and veggies, adding kelp to your soil is an excellent way to boost the iodine levels of your own produce. One may also consider iodine supplements in the form of potassium iodide or natural kelp.

Brett Friedman Nutritional Medicine Consultant for Wondermins
Advanced Diploma of Nutritional Medicine (Naturopathy; Nutrition), MSc.(Med) Genetic Oncology, BSc.(Hons) Microbiology


Always read the label and use as directed. Vitamins and minerals are supplementary to and not a replacement for a balanced diet. If symptoms persist, see your healthcare professional. Wondermins, Auckland. NA 10330.