The meat of Australia's bush kangaroo may be the highest known source of the healthy fat CLA, a University of Western Australia and CSIRO sponsored PhD student has discovered.
CLA (conjugated linoleic acid) is found in dairy products, beef and lamb.
In trials, CLA has been shown to possess potential anti-carcinogenic and anti-diabetes properties, in addition to reducing obesity and atherosclerosis (high blood pressure).
PhD student Clare Engelke has found that the meat-fat of the Western Grey kangaroo in some circumstances has up to five times higher CLA content than lamb.
"Australian pastoral lamb is considered to be a relatively high source of CLA, so I was surprised to find the levels in kangaroos were that much higher in comparison," Ms Engelke said.
Her study is believed to be the first research on CLA levels in kangaroos available in the public domain.
In collaboration with the University of Adelaide, Ms Engelke compared CLA levels in Western Grey kangaroos and lambs from the Badgingarra region in Western Australia and analysed tissue samples of other Western Greys, Red and Eastern Grey kangaroos from different areas of Australia.
Although kangaroos are not a true ruminant, Ms Engelke became interested in researching Australia's national icon for her PhD in agricultural science because, like ruminants, kangaroos ferment food in their foregut. CLA is produced in the stomach and tissues of ruminant animals such as sheep and cattle during the digestion process.
In Australia, kangaroo meat has traditionally been used for pet food but the European market for the meat grew by 30 percent following the 2001 outbreak of foot and mouth disease.
CSIRO Project Leader Dr Andre Wright said kangaroo meat was very lean with a two per cent fat content.
"Kangaroo meat also has high levels of protein, iron and zinc," Dr Wright said.
Ms Engelke is now working to identify the 'bugs' in the kangaroo's foregut responsible for producing CLA.
"My aim is to find out which microorganisms and circumstances are responsible for CLA formation and why kangaroo meat appears to be the highest known source of these healthy fats," Ms Engelke said.
If successful, it may be possible to increase the CLA content of other meats and products to increase potential health benefits to consumers.
How many kangaroos are there in Australia?
It is estimated there are around 35 million kangaroos in Australia. Five of the 48 species of kangaroo are harvested for meat. The kangaroo meat industry harvests approximately two million animals per annum and provides employment in regional Australia.
What is the nutritional composition of kangaroo meat?
Kangaroo meat is very lean and has less than two per cent fat content. Kangaroo meat also contains very high levels of quality protein, iron and zinc. Due to its leanness, kangaroo meat must be cooked with care to avoid overcooking. A doctoral study undertaken by Clare Engelke, sponsored by the University of Western Australia and CSIRO Livestock Industries, indicates that kangaroo meat is the richest known natural source of CLAs in currently available literature. Dairy milk was previously the highest known source of CLAs, followed by beef and lamb.
What are conjugated linoleic acids (CLA)?
Conjugated linoleic acids (CLA) are polyunsaturated fatty acids that have been the focus of researchers over the past two decades. In animal experiments, CLA have been shown to reduce obesity and heart disease and have anticarcinogenic properties. The majority of research into CLA has focused on the health benefits of CLA to humans. These benefits have only properly been demonstrated in animal models and human cells, not humans themselves. However, one study in humans detected an inverse (reduced) relationship between milk consumption and breast cancer risk. Tests of CLA benefits in humans have been limited by ethical considerations - for example, the illnesses that CLA are reported to protect against cannot be induced in human subjects, nor can lifestyle factors be controlled as easily as with mice or rats in a laboratory. Currently, scientists do not yet have a definitive answer for the amount of CLA required to produce beneficial effects in humans.
Where are CLA found?
CLA are found in products made from the meat and milk of ruminant animals (such as sheep and cattle). Many other foods contain CLA, including vegetable oils, eggs, seafood, poultry and pork but at very low levels. The levels of CLA found in ruminant products depend upon the diet of the ruminant animal, and are generally higher if the animal is grazing on fresh, green pasture. Australian beef and sheep grazed on a pastoral-based grazing system are considered to be richer sources of CLA than lot-fed cattle. Ruminant animals have high levels of CLA because they have bacteria in their gut (rumen) that produce CLA naturally during digestion of feed and later in fat tissues.
What are CLA levels in kangaroo meat?
Kangaroos can have as much as five times more CLA in their fat than ruminants. The level of CLA in kangaroos depends on their diet, as it also does in ruminant animals. Clare Engelke, a PhD student, is studying the level of CLA in kangaroo tissues and attempting to identify the microbes that produce CLA during digestion and why these CLA occur at relatively high levels. In collaboration with the University of Adelaide, she tested the CLA content of Western Grey kangaroos from the Badgingarra region of Western Australia with lambs and found that the CLA levels in kangaroos there were up to five times higher than in the lambs.
Kangaroos are not true ruminant animals but, like ruminants, they ferment feed in their foregut. Ms Engelke also tested Western Grey kangaroos from other areas of Australia and other species - Red kangaroos and Eastern Greys. The CLA levels in these kangaroos were high but varied according to diet, with kangaroos from areas that had fresh pasture proving the richest source of CLA.
At the time of publishing, there were no other reports of CLA levels in kangaroo meat. Although there have been reports of conjugated dienes in quokkas, wallabies and kangaroos, no CLA levels have been recorded.
Is kangaroo meat good for you?
Kangaroo is a uniquely Australian game meat that is lean and healthy with around two per cent fat and very high levels of quality protein, iron and zinc. Because kangaroo meat is so low in fat content, the meat must be cooked quickly to avoid overcooking. Kangaroos are harvested by licensed shooters in accordance with a strict code of practice. Kangaroo exports are subject to stringent inspection requirements by the Australian Quarantine and Inspection Service (AQIS) under the Australian Standard for the Hygienic Production of Game Meat. The discovery of high levels of CLA (healthy fats) in kangaroos may also increase the health benefits of the meat.
Who eats kangaroo?
In Australia, most kangaroo meat is currently sold for use as dog and cat food. However, kangaroo is increasing in popularity in Australia, with high quality kangaroo steaks available in supermarkets. Kangaroo meat is also increasing in popularity in Europe, with European exports rising by 30 per cent following the 2001 UK foot and mouth disease outbreak. Outbreaks in Europe of mad cow disease have also increased international interest in kangaroo meat. In 2002, the Balkans imported more than 2000 tonnes of kangaroo meat, where it is used for steaks, salami or sausages.