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Food Sources of Conjugated Linoleic Acid

Trans fat has a much deserved negative reputation. But there's one type of trans fat that is actually beneficial. Conjugated linoliec acid is a trans fat, but it has a unique structure that lowers its melting point and gives it beneficial health effects. Just as surprising as the existence of a healthy trans fat is the source of this good fat: beef and dairy products. You may have seen grass-fed beef advertised in your local market and wondered why that should be particularly special. It turns out grass-fed cows is one of the highest concentration food sources of conjugated linoleic acid.

  1. Identification

    • Linoleic acid is a type of omega-6 fatty acid. A subset of at least 28 different structures for the same basic molecule has been found to have surprising qualities. Called conjugated linoleic acids (CLA), these fatty acids have been shown to have anticarcinogenic properties. Further research has indicated a potential for certain types of CLA to prevent cardiovascular disease, lower fat around the midsection, and increase insulin sensitivity.

    Ruminants

    • Some forms of conjugated linoeliec acid are naturally occurring and can be obtained from certain foods. Principal among these are meats and animal products from ruminant animals. Ruminants are animals, like cows, that have more than one stomach. Digestion in these animals begins in an organ called the rumen, where CLA is formed. The animal regurgitates and rechews its cud before eventually digesting the CLAs, where they enter the meat and milk of the animal. Common ruminant food sources include cattle, goats, sheep and deer.

    Grass-Fed

    • Most beef sold in the United States is not grass-fed. Instead, most cattle is raised on grain and other types of feed. The majority of these animals are also treated with hormones and antibiotics. Organic, grass-fed cows have 300 to 500 percent more CLA than cattle raised on other feeds. This is true of the beef, butter, milk and cheese produced from grass-fed cows. Grass-fed cows are the best source of CLA in the American diet.

    Kangaroo and Poultry

    • The highest concentration of CLA in all foods, however, is contained in kangaroo meat. Raised wild in Australia, kangaroo meat is sold in 55 countries including the United States, though it is relatively difficult to find. The meat is typically ground and used in sausage. Kangaroo has only been legal to eat since 1980 and is still not a staple meat in any diet, even in Australia. CLAs are also found to a much lesser extent in poultry. The CLA in eggs withstands the cooking necessary to render it safe from food-borne pathogens.

    Nonmeat sources

    • Fats from vegetable sources are usually low-quality sources of CLA. The major exceptions are heat-treated linoleic acid in safflower and sunflower oils. A variety of synthetic CLAs are also being studied, some of which are available as supplements and, potentially, to enrich other foods. Human breast milk contains some CLA and is the first dietary source many people encounter.

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