CLA is a fatty acid found in beef and dairy fats. Scientific interest in CLA was stimulated in 1988 when a University of Wisconsin researcher discovered its cancer-fighting properties in a study of rats fed fried hamburger. CLA cannot be produced by the human body, but it can be obtained through foods such as whole milk, butter, beef, and lamb.

"The interesting thing is that dairy cattle that graze produce higher amounts of CLA in their milk than those which receive conserved feed, such as grain, hay, and silage," says Agricultural Research dairy scientist Larry Satter. This is true even when the nongrazers eat pasture grass conserved as hay.

Satter, who is based at the Dairy Forage Research Center in Madison, Wisconsin, conducted a study comparing the amount of CLA in milk from cows grazing on pasture to the amount from cows fed hay or silage.

His findings:

Pasture-grazed cows had 500% more CLA in their milk than those fed silage.

Larry Satter is at the USDA-ARS U.S. Dairy Forage Research Center, 1950 Linden Lane, University of Wisconsin, Madison, WI 53706; phone (608) 264-5353, fax (608) 264-5147.

CLA may be one of the most potent cancer-fighting substances in our diet.

In animal studies, as little as one half of one percent CLA in the diet has reduced tumor burden by more than 50 percent.

CLA has also been shown to reduce body fat in people who are overweight.

by Mary Shomon

A double-blind, randomized, placebo-controlled study, published in the December 2000 issue of the Journal of Nutrition found that CLA reduces fat and preserves muscle tissue. According to the research project manager, an average reduction of six pounds of body fat was found in the group that took CLA, compared to a placebo group.

The study found that approximately 3.4 grams of CLA per day is the level needed to obtain the beneficial effects of CLA on body fat.

Dr. Michael Pariza, who conducted research on CLA with the University of Wisconsin-Madison, reported in August 2000 to the American Chemical Society that "It doesn't make a big fat cell get little. What it rather does is keep a little fat cell from getting big."

Pariza's research did not find weight loss in his group of 71 overweight people, but what he did find was that when the dieters stopped dieting, and gained back weight, those taking CLA "were more likely to gain muscle and not fat.'' In a separate study conducted at Purdue University in Indiana, CLA was found to improve insulin levels in about two-thirds of diabetic patients, and moderately reduced the blood glucose level and triglyceride levels.

CLA has been the subject of a variety of research in the past several years, and findings also suggest that some of the other benefits of CLA include the following:

• Increases metabolic rate -- This would obviously be a positive benefit for thyroid patients, as hypothyroidism -- even when treated -- can reduce the metabolic rate in some people.
• Decreases abdominal fat -- Adrenal imbalances and hormonal shifts that are common in thyroid patients frequently cause rapid accumulation of abdominal fat, so this benefit could be quite helpful.
• Enhances muscle growth -- Muscle burns fat, which also contributes to increased metabolism, which is useful in weight loss and management.
• Lowers cholesterol and triglycerides -- Since many thyroid patients have elevated cholesterol and triglyceride levels, even with treatment, this benefit can have an impact on a thyroid patient's health.
• Lowers insulin resistance -- Insulin resistance is a risk for some hypothyroid patients, and lowering it can also help prevent adult-onset diabetes and make it easier to control weight.
• Reduces food-induced allergic reactions -- Since food allergies can be at play when weight loss becomes difficult, this can be of help to thyroid patients.
• Enhances immune system -- Since most cases of thyroid disease are autoimmune in nature, enhancing the immune system's ability to function properly is a positive benefit.

If you're interested in taking CLA to help with weight loss, keep in mind that it's not a magic, and you will need to start a program of diet and exercise in order to successfully lose weight and keep it off.

Conjugated linoleic acid (CLA) is a mixture of positional and geometric isomers of linoleic acid, which is found preferentially in dairy products and meat. Preliminary studies indicate that CLA is a powerful anticancer in the rat breast tumor model with an effective range of 0.1-1% in the diet.

Conjugated linoleic acid is unique because it is present in food from animal sources, and its anticancer efficacy is expressed at concentrations close to human consumption levels.

Conjugated linoleic acid and atherosclerosis in rabbits Lee K.N.; Kritchevsky D.; Pariza M.W. Food Research Institute, Dept. Food Microbiology/Toxicology, University of Wisconsin-Madison, 1925 Willow Drive, Madison, WI 53706 USA Atherosclerosis (Ireland), 1994, 108/1 (19-25)

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