The Macadamia Nut Tree Produces Nutritious, Delicious Nuts that Are Useful in a Cholesterol Lowering Diet.

The macadamia nut tree is an evergreen rainforest tree of the proteaceae family. It is either a smallish tree, suitable for backyard gardens or commercial plantations, growing to about four metres in height (macadamia integrifolia) or a much taller tree (macadamia tetyraphylla) reaching eighteen metres or so. Both species produce hard shelled nuts, which are highly nutritious.

Indigenous to the rainforests of Eastern Australia, the trees’ healthy nuts are grown commercially with great success, but it took about seventy years, until 1953, to develop efficient processing equipment. One drawback to the processing of the crops, in the early days of the industry, was the extreme hardness of the shells surrounding the delicious round nuts. If you have tried to shell them yourself, you know what a very frustrating experience that can be.

macadamia nuts almost ready for harvestMacadamia nut tree, nuts almost ripe

However, once technologies for harvesting, processing and quality control had been developed and implemented, Australian macadamias became sought after world-wide, earning a reputation for consistent excellence.

Named after scientist, John McAdam, macadamias were well known to the indigenous inhabitants of the rainforest who enjoyed the nuts along with other rainforest foods available to them and sometimes traded them with early European settlers. Known to some groups as ‘kindal kindal’, to others as gyndl, jindilli or boombera, when fully ripe the nuts would drop to the ground, or be helped on their swift downward journey by various species of parrots.

mmacadamia nuts from domestic garden, ready for shelling and eatingMacadamia nuts gathered from a suburban garden

If picked when mature but before they drop, macadamia nuts need to be left to dry before they are cracked open as, otherwise, the still soft nut will adhere to the inside of the shell. If you have a macadamia nut tree growing in your backyard you can test the nuts for dryness, once picked, by shaking them. If you feel the vibrations and hear a sound of the nut rattling around in its shell, it is ready!

If you don’t have purpose-built nut crackers try cracking the shell just enough to prise it open so that you can then remove the nut undamaged. I used to do this in a normal workshop vice but a specially designed tool for home use is better!

Grown in fertile soils in areas of high rainfall, macadamia nut trees have shiny, dark green, spiky leaves and perfumed cream flowers, which are replaced by tiny nuts once the flowers are shed. Nuts mature in the Australian summer and through to Spring (February to September).

The outer husk, which surrounds the nut, is removed and the nuts in their shells allowed to dry for about three weeks or until the moisture content reaches approximately 1.5% and the nut shrinks away from its encasing shell.

Various styles are then developed, dry roasting being popular; my preference is for the raw nuts, with no salt or other flavor added. Quality control is of the utmost importance in this Australian industry, all macadamia products, which have a long shelf-life, being subjected to rigorous inspections and controls.

Macadamia oil is cold-pressed and has a wonderful aroma and taste whether used in salads or for cakes or stir-frys- and macadamia nut cookies! It is also a very useful component of skincare products.

Healthy Nuts

Macadamia nuts are very nutritious, having the highest amount of beneficial monounsaturated fat of all nuts and a good amount of essential amino acid proteins. They also contain carbohydrates and dietary fibre, calcium, potassium, sodium, phosphorus, selenium, magnesium, thiamine, riboflavin, folate, niacin, zinc and iron as well as vitamins B, C and E.

Research has shown that macadamia nuts are helpful in reducing total and LDL cholesterol levels when eaten regularly.

But a warning: some people are allergic to macadamia nuts, as they may be to other nuts. This caution obviously also applies to skincare products made using macadamia oil.

Macadamia nuts should never be given to dogs, for whom an ingestion of these human ‘treats’ could be fatal.

It is likely that macadamia nuts will soon be used mostly because of their health promoting properties as well as for their superb taste and crunchy texture. Their vitamin, mineral, fibre, monounsaturated fats and phytochemical content (an area of current scientific enquiry) acts positively on general health and is even useful in a weight reduction programme – now there’s a surprise for those who have thought that nuts were a guilty treat!

Of course if you choose to eat them deep fried (roasted in oil) or salt laden, then you haven’t done any basic research! If you are worried about the number of calories in nuts, just substitute them for other fatty snacks and you’ll be ahead in energy and general health by leaps and bounds.

Eaten raw as part of a well balanced diet low in saturated and trans fats, macadamia nuts have been shown to improve inflammation and reduce the risk of heart disease, high blood pressure, diabetes and some cancers. It seems that they do this through an interaction with body processes, as yet not well understood (at least not by me!).

Having read the results of various studies these are my generalised conclusions but if you want facts and figures it is best to do read findings of properly controlled and recorded research yourself.

Will you now be on the lookout for a beautiful macadamia nut tree perhaps growing somewhere near you?



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macadamia nuts hanging from tree

Macadamia nuts, almost ripe


the macadamia green covering splits to show the hard shell beneath

The hard shell of the macadamia nut, seen beneath its split outer covering, is very hard to crack.


macadamia leaves

Slightly spiky leaves of the macadamia tree


macadamias just picked

Freshly picked, glossy macadamia nuts


young macadamia tree

Young macadamia tree growing in a garden