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The fast-rising promise of CLA

Conjugated linoleic acid is a natural part of beef and dairy foods that science is revealing as significant health booster, opening new market opportunities.

Thank goodness for the cow.

That's one of the first sentiments that pops to mind when viewing a "virtual rumen" contraption in the laboratory of cattle researchers Dr. Bob Forster and Dr. Ron Teather, at the Agriculture and Agri-Food Canada (AAFC) Lethbridge Research Centre.

The Rumen Fermentation Model, an assemblage of beakers, various apparatus, compounds and chemicals, provides a rudimentary model for the researchers to investigate how various micro-organisms behave in the rumen environment.

"Rudimentary" is the operative word. Despite its external simplicity, the bovine animal and the rumen it contains is a remarkable piece of biology that is extremely valuable to humans and impossible to replicate. As scientists learn more about the inner workings of the rumen, it is increasingly recognized as one of the most sophisticated and unique biological environments.

"The rumen is like a big, complex combination of aquarium and composter," explains Teather, a rumen microbiologist. "In a dairy cow, it has a 100 litre volume. The cow keeps it warm, puts feedstuffs in, and takes away waste products. And that environment supports the densest microbial community – and the best at degrading plant fibre – that exists. The rumen really is exceptional compared to any other biological system."

Now Canada's beef and dairy industries are poised to take advantage of this unique system like never before, as researchers learn more about rumen processes that have benefits for increasing the health and commercial value of beef and dairy products. One of the latest and most promising of these is the unique ability of the rumen to facilitate the development of conjugated linoleic acid (CLA) – a natural "good fat" that early animal studies have linked to considerable potential for battling a range of chronic diseases in humans, including cancer and heart disease.

As researchers learn more about CLA and how it is produced in ruminant animals, they are identifying ways to increase natural CLA levels in dairy and beef products through simple livestock feeding strategies and other methods. This progress is creating an opportunity to enhance consumer perceptions of the health value of these products. It is also opening the door for market expansion into new CLA-enhanced branded products, and generating potential for increased production efficiencies.

"Research has indicated that CLA is a very significant nutrient. The health benefits for consumers are very promising," says Dr. Bob Forster, also a rumen microbiologist.

Roundtable discussion with leading CLA researchers

In previous research funded by the Canada Alberta Beef Industry Development Fund (CABIDF), Forster and Teather, along with colleague Dr. Randy Weselake of the University of Alberta, investigated ways to enhance the levels of CLA-producing bacteria in the rumen of beef cattle. Their research revealed an enzyme, from the Butyrivibrio fibrisolvens bacteria in the rumen, which plays a role in the creation of CLA. (For more information on this research, click here.)

In the following "Perspective on Beef Science" discussion, these scientists and other Alberta colleagues in various areas of CLA research offered perspective on three key questions related to the potential for Canada's beef industry to capitalize on the benefits of CLA. Their comments provide an insider's perspective on of what's fast becoming a rising star for Canadian beef science.

Along with Forster and Teather, participants in the discussion included Dr. Spencer Proctor, Director of Metabolic and Cardiovascular Diseases Laboratory, University of Alberta; Dr. David Glimm, cattle genomics researcher, University of Alberta; Dr. Erasmus Okine, ruminant nutritionist, University of Alberta; Dr. Priya Mir, ruminant nutritionist, AAFC Lethbridge Research Centre; and Dr. John Basarab, animal scientist, Alberta Agriculture, Food and Rural Development (AAFRD);

Q: What do we know about the human health benefits of natural CLA found in beef?

Dr. Spencer Proctor: We are very excited and encouraged by the new research knowledge on CLA. We are learning that CLA is important for many human biological systems and has excellent potential to support human health.

In particular, natural CLA found in beef products is showing considerable potential for human health benefits related to cancer, heart disease, obesity, diabetes, kidney disease and bone density.

Dr. David Glimm: Synthetic forms of CLA have been developed for both commercial supplements and research purposes. However the CLA found naturally in dairy and beef products may offer the best avenue for developing CLA health potential.

This is because while there are many different isomers, or types, of CLA, two of these have been studied most extensively and have the strongest links to health benefits. These two isomers, CLA 9,11 and CLA 10,12, are the ones found most prominently in dairy and beef products.

Also known to be present in beef and dairy products is vaccenic acid, which we now know is a precursor to CLA 9,11. This precursor is converted into CLA by a natural human enzyme once inside the human body.

Q: How much CLA is found in beef products, and how much can it be increased?

Dr. Erasmus Okine: The more we learn about the ability of the rumen to produce natural CLA, the more good news there is for consumers and for the beef industry. We know that rumen processes produce CLA that is transferred into beef products. We also know levels of this natural CLA can be increased substantially in these products through simple changes to common livestock production practices.

For example, dietary modifications such as including oilseeds, or more grass and forage in cattle diets, can greatly increase CLA.

Dr. Priya Mir: The specific amount of CLA typically found in beef products depends upon the amount of fat in the muscle. Cuts with higher fat will deliver higher CLA. Also, meat from breeds that have higher intramuscular fat or marbling fat will deliver higher levels of CLA.

Based on the studies conducted so far, it is estimated that the average concentration of CLA is about 27.5 mg/ 100g of beef. That's in meat derived from Canadian beef cattle raised under conventional conditions.

The amount is higher if you include vaccenic acid, which is a precursor to CLA, in the calculation. Typically, vaccenic acid levels of 2.12 mg/ g of total fat are found in general muscle and 2.61mg/ g of total fat are found in skirt muscle.

Based on our research and that of our colleagues, indications are CLA can consistently be doubled with simple modifications to production practices. We have even observed a tripling.

Artificial rumen fermentation system at AAFC Lethbridge

Dr. Bob Forster: The focus of our research has been to find ways to enhance CLA production in the rumen of beef cattle, so there will be a higher level in the meat product. A lot of our work has been culturing rumen bacteria in order to identify new bacterial populations linked to CLA production. If we are able to isolate new populations responsible for producing this desirable compound, we expect it could mean significant benefits for the beef industry and consumers.

This is just one additional avenue among a number being explored by researchers in different areas to increase CLA levels. The research effort as a whole remains at a relatively early stage, but we're seeing consistent progress and some major steps are expected over the next several years.

Q: What's the potential of further research, and where are we ultimately headed?

Dr. Ron Teather: Our work in exploring the rumen environment is a good example of how the potential of CLA research has expanded greatly over the past decade, as our capacity to investigate processes at a molecular level has increased.

Until recently the rumen was just a black box - you'd put something in and see what comes out at the other end. But trying to figure out the complexities of how it works, so you could guess how you might get it to perform better, was a big challenge. Today's methods give us a much better understanding. For example, we used to think the rumen contained 30 or 40 different kinds of bacteria - now we realize it contains more than 500.

Many of those are bacterial that hold the key to many advantageous uses – CLA being just one of them. Potential has expanded in a similar way in other research areas.

Dr. John Basarab: Imagine a possible new niche beef product: grass-finished CLA enriched beef. That's one of the possibilities.

CLA progress opens the door to new ways to promote beef as part of a healthy diet. There will be many opportunities to develop beef products with identified CLA levels, including enhanced CLA levels.

The Omega 3 example is good model. We can develop similar products and capture similar market opportunities with CLA. With continued support for the various research and development efforts, we hope to see CLA-labeled products on the shelves within the next several years. CLA has potential to be a major asset for the beef industry for many years to come.

Support for the development of this Perspectives on Beef Science article was provided by the Canada Alberta Beef Industry Development Fund.

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