Evergreen macadamia trees grow in North Australia.
5000 years ago, Aboriginal Australians already knew of macadamia’s healing and nourishing properties, and they deemed the nuts sacred. Macadamia trees got their modern name only in 1857, when a German botanist Frederick Muller named them after the renowned Australian chemist and political figure John MacAdam. In 1880s the first macadamia plantations appeared in Australia, but they weren’t large, and macadamia remained an exotic and expensive treat for quite a while longer. In 1920s macadamia nuts were planted in the Hawaii and soon they became famous first on the islands, then in the continental US, and later—all over the world. Today the Hawaii are the biggest supplier of macadamia nuts.
Macadamia nuts are fairly expensive. The trees bear fruit 7 years after they were planted, and the yield from one tree is not very large.
There are several types of macadamia trees, and the only nuts that humans can eat belong to Macadamia integrifolia and Macadamia ternifolia — all the rest are toxic, because they contain cyanogenic glycosides, similar to those found in apricot pits and almond.
Dog lovers should note that macadamia nuts can be dangerous for their pets — even the ones that people can eat without a problem are toxic for dogs.
Macadamia poisoning is followed by cramps and sharp pain in the stomach and joints. Fortunately, most symptoms disappear on their own within a couple of days.
Macadamia nuts are close to cashew in taste and nutritional properties, while macadamia oil is more similar to the fat of sea mammals and some furry animals.
Cosmetic professionals often nickname it ‘vegetable mink oil’ because of this similarity—the real mink oil hasn’t been used for skin care in a long time now for ethical reasons. What makes these oils so similar is palmitoleic acid, also known as omega-7 acid. Macadamia oil contains up to 22% of it, and mink oil—up to 18%, which means that the former has an even stronger impact on the skin. Palmitoleic acid is produced in small quantities by the skin’s sebaceous glands, and its synthesis decreases with age, making the sebum less soft and nutritious. The change in the sebum composition is one of the main reasons of the skin’s dryness and hypersensitivity developing with age. Similar changes occur in the sebaceous glands when oily or problem skin is being treated too aggressively—the skin continues producing the sebum, but it becomes more fluid and stops retaining moisture on the skin’s surface.
Macadamia oil helps the skin compensate for the omega-7 deficiency. It is especially beneficial for the skin that’s starting to age or needs rehabilitation after acid or retinoid-based treatment.
As for unsaturated fatty acids, macadamia oil contains up to 55% of oleic acid, but only 1–3% of linoleic acid, which makes it different from regular nut and seed oils—grape seed, sunflower and almond. Macadamia oil contains more saturated fatty acids than the abovementioned oils—up to 20%, which makes it unusually thick and rich. As other oils, macadamia oil contains vitamins and minerals.
It is not very rich in vitamins E and C, so it doesn’t have acute antioxidant properties — it is not so protective as it is restoring. Niacin in the oil enhances microcirculation in the skin — another good reason to include it into the ageing skin care routine. And the mineral composition is uncommon and quite rich: among other things macadamia oil contains copper, zinc and iron, which stimulate the skin’s healing and regeneration.
Macadamia has quite a high contents of proteins — up to 10% which also enhances the rehabilitation of damaged skin and even helps restore the syntheses of the deep skin structural proteins (collagen and elastin).
Macadamia oil is recommended for restoring the skin after UV damage and even to treat photosensitivity disease. And on top of this macadamia oil has a curious effect on the hair—it smoothes it out from roots to ends, making it thicker and more elastic. On the whole, macadamia oil or the ‘vegetable mink oil’ can be named a ‘winter oil’ saving the skin from the wind and the frost and helping it restore after the summer vacation. Macadamia oil rarely causes allergic reactions, although of course the possibility cannot be entirely ruled out.