Wattle
The seeds of the Acacia (Acacia spp.) have been gathered for food by Indigenous Australians for tens of thousands of years. Also called wattle, the Acacia is a genus of plants in the legume family known also in Africa and the Mediterranean since the time of Herodotus, where the wood was harvested for shipbuilding, the bark for ropemaking, the leaves as an animal fodder and the branches for firewood.1 In Australia, Acacia is the second largest genus of plants containing over 700 species and many of them produce an abundance of seeds that were valued in some parts as a staple crop.2
People have inhabited this country for over 50,000 years and used fire to manage the landscape in a mosaic pattern of low-level burns. This pattern was determined in part by the fertility of the soil, where the better soils were used for food production, while the worst were left as forests.3 Burning the landscape favours plants such as Acacia whose seeds require fire to germinate, something that is evident in landscapes following bushfires where the first plants to grow are usually wattles.
When you ride the boundaries of a farm, cutting away the saplings that grow through the fences, you can often see stands of these wattles with shiny trunks covered by weeping sap. If you look closely you discover that the sap oozes from holes in the bark caused by an insect infestation. This indicates that the wattle is stressed by growing in very poor soil, or is suffering from a shortage of water.
Poor soils are a feature of Australia’s ancient eroded landscape and nutrient deficiencies can be a problem for trees as well as the animals and people living on it. The soils are commonly deficient in iodine and other trace minerals such as boron or selenium which can make animals sicken, and eating them will perpetuate the problem. Hypothyroidism is in fact a common problem in Australia.
Calcium and magnesium imbalances are also common, made worse by the use of artificial fertilisers that acidify the soil. This acidity locks up trace minerals such as copper, boron, cobalt, sulphur, magnesium, zinc and potassium which are essential cofactors in numerous biochemical processes. You can identify this problem in paddocks by the presence of certain dominant plants which prefer acidic soil: bracken, capeweed, blackberry, thistle and nettle.4
Dolomite or lime can be used to remedy such an imbalance by applying it to the soil or putting it in animal licks, along with other trace minerals, and a friend of mine likes to tell the story that when she was pregnant she had an irresistible urge to eat dolomite tablets. As you would expect, such periodic cravings often come when there is an increased demand for nutrients, and can be at the root of such debilitating conditions as post-natal depression.
Nutrient deficiency causes physiological stress and reduces immune defences. While mostly due to unsatisfactory dietary choices today, historically it was caused by an unfamiliarity with the landscape and native plants, inappropriate farming practices, and an inability to store fresh foods due to a lack of refrigeration. The white colonial settlers lived on a staple diet of white flour, refined sugar, tinned or salted meat, jam and tea, and their poor condition astonished the dentist Dr Weston Price in the 1930s who studied the stature, teeth and dental arches of many peoples around the world. In contrast to the settlers, Dr Price was impressed by the Aboriginals he found still living a traditional lifestyle, whom he thought an example of physical perfection.5
Scurvy was a common condition suffered by the white settlers despite an abundance of available fruit, berries, legumes and vegetables such as warrigal greens, purslane, sow thistle and other nutritious foods eaten by the Aboriginals. These kind of foods enabled the Aboriginals to subsist on the land while living to an advanced age, although accurate historic records for their longevity were not kept due to the government policy of the time which denied previous land title and use. This policy excluded Indigenous Australians from their traditional lands, forced them to resettle for protection from confrontations with settlers, and then neglected them. By the time the government policy changed from one of mere preservation to active assimilation, and accurate records of the Aborigines were kept, their diet was already comprised largely of the ‘displacing foods’ of the colonists which Dr Price considered the leading cause of the general state of physical degeneration he noticed all around the world. The situation has little improved for Aboriginal people who currently live in urban areas, centralised communities, rural towns or on cattle stations, with a life expectancy almost twenty years less than other Australians.6
Acacia seeds from more than thirty species were collected from trees, off the ground, or out of the nests of seed-gathering insects living around the trees.7 The seeds were usually removed from the pods by beating with a stick or yandying, and then ground on a rock together with water to make a paste. The paste was then either eaten raw or formed into a dough and cooked on the coals of a fire in order to make a type of unleavened bread called damper.8
Seeds from Acacias, as well as grass seeds and yams, contributed a significant part of the protein in the diet in Central Australia because of their abundance and seasonal reliability, while coastal tribes sometimes disdained them in favour of the protein obtained from marine creatures. Commonly found wattles with edible seeds include mulga (Acacia aneura), dogwood (Acacia coriacea), witchetty bush (Acacia kempeana), strap wattle (Acacia holosericea) and bramble wattle (Acacia victoriae).7 The seeds contain high amounts of protein, carbohydrate, and about 10% unsaturated fat. They are high in energy while the fibre comes in the form of slowly-absorbed starch which is ideal for regulating the bowel.2
The diet was not, however, largely vegetarian like that of the people of the Mediterranean, because the desert people ate a considerable quantity of small mammals, lizards, birds and grubs, yet legumes often had to be relied on for survival. Even so, replacing nutritious legumes and grass seeds with wheat flour, something apparent in even remote settlements, has meant the loss of a nutrient-dense food. People consuming such convenience foods also lose the exercise needed to gather the wild bushfood, a disastrous combination associated with the development of degenerative diseases such as obesity, diabetes and heart disease. Community stores in these settlements now provide upwards of 90% of the dietary intake, as do supermarkets in any urban part of Australia, where most people get their food.9
Wattle seeds also contain anti-nutrients, a description we give to substances which inhibit the absorption of vital nutrients during digestion, or are actually toxic in some way. These might be inhibitors of enzymes or constituents such as phytates which sequester minerals like iron and iodine and so reduce absorption. Wattle seeds are fortunately low in phytates but high in protease inhibitors which can nevertheless be deactivated by soaking them overnight. Roasting also reduces the level of protease inhibitors, phytates and oxalate, making wattle seed a good protein source for urban people imitating a palaeolithic diet.10
The Aboriginals also eat the gum oozing from the bark of the wattle, mulga and other Acacias. This sweet gum is collected from the trees and then formed into balls, but it can also be combined with nectar, as well as the starchy secretions of insects, and used to make drinks. These sweet secretions are formed by lerps living on the branches and leaves of mulga trees and other Australian plants; they are a kind of sap-sucking bug called psyllids. The red mulga lerp produces a tasty nectar, while the mulga gall-wasp produces an edible food on the tree called a mulga apple, because it resembles dried apple in taste. Mulga apple was valued by the Aboriginals and bushmen alike, while mistletoe, a plant that parasitises the mulga bush, also produces fruits that are edible.
The witchetty grub can also be found attacking the roots of Acacias and they are dug up and eaten raw or roasted on hot coals, giving a rich nutty flavour. Honey ants are also much valued by the Aboriginals who find them making their nests nearby the wattles. These ants, grubs, wasps and lerps are an insect-bounty in addition to the abundant edible seeds available to the experienced gatherer from what is a common, but nonetheless invaluable plant. Furthermore, the timber of the mulga provides a very tough wood suitable for making tools and weapons, such as digging sticks, blades, boomerangs and woomeras.
References:
1. Livingston. Edible Plants And Animals. US: Facts On File, Inc.; 1993.
2. Lister. Acacia in Australia: Ethnobotany and Potential Food Crop. Progress in new crops. ASHS Press 1996;Oct.
3. Pascoe B. Dark Emu, Black Seeds: agriculture or accident? Magabala Books; 2014.
4. Coleby P. Natural Goat Care. Australia: McPherson’s Printing Group; 1993.
5. Price W. Nutrition and Physical Degeneration. 6th ed. US: Price-Pottenger Foundation; 2000.
6. Hetzel BS. Historical perspectives on indigenous health in Australia. Asia Pac J Clin Nutr 2000;9:157–63.
7. Low T. Wild Food Plants Of Australia. Angus & Robertson; 1991.
8. Isaacs J. Bush Food, Aboriginal Food And Herbal Medicine. Weldon; 1987.
9. Lee A. The transition of Australian aboriginal diet and nutritional health. World Rev Nutr Diet 1996;79:1–52.
10. Ee KY, Yates P. Nutritional and antinutritional evaluation of raw and processed Australian wattle (Acacia saligna) seeds. Food Chem 2013;138:762–9.