Want a Natural Way to Fight Cancer?
Try a Little CLA from the Pasture

By Mary Myers
Logan, Utah

From: "The Stockman Grassfarmer"

CLA or conjugated linoleic acid is a natural anti-carcinogen. It is a fatty acid that occurs naturally in many foods and is especially high in milk and meat from ruminant animals. The acid is produced by bacteria in the rumen. The only way humans can get CLA is by consuming dairy products and beef. CLA has been shown to inhibit cancer growth in laboratory animals.

Since low fat diets have become popular, people have been cutting out not only fat, but CLA as well. Studies have shown that CLA slows the progress of some types of cancer and heart disease, and it appears to actually help reduce body fat and increase lean muscle mass.

Dr. Tilak Dhiman, a University of Utah animal scientist, is examining ways to increase the CLA content of milk, cheese and meat. Dr. Dhiman said, "We must distinguish between types of fats. We tend to think that all fat is bad for us, but nutrition is very complex and we don't know everything about it."

Dr. Dhiman as well as others have found that the CLA content of milk is as much as five times higher when cows graze green, predominantly ryegrass or on natural pastures than when they eat diets consisting of 50 percent conserved forage, such as alfalfa and corn silage and 50 percent grain. Researchers also found that feeding higher amounts of conserved forage in the diet increases CLA content of milk. But, they also found that the CLA level is still not as high as milk from cows grazing pasture.

According to Dr. Dhiman, it is possible that something in green grass enhances the growth of the particular bacteria in the rumen that is responsible for producing CLA. Or it may be that grazing cows have different microbes in the rumen than cows fed inside the barn.

"We cut our consumption of CLA when we changed the way we feed our animals," Dr. Dhiman. He also noted that 30 or 40 years ago animals mostly grazed on pasture. Now their feed is controlled, which might be having a negative impact on human health. "Today we are producing milk more efficiently with controlled feeding," said Dr. Dhiman. "However, we need to couple this efficiency with milk and meat quality."

Dr. Dhiman has also determined that CLA levels can be boosted by supplementing the cow's diet with roasted cracked soybeans added to alfalfa and corn silage. This supplementation resulted in increases of CLA content in milk. When soybean oil and linseed oil were added to dry feed in amounts comprising 2-4 percent of the cows' diet, CLA levels in their milk came close to those of cows eating green pasture. Higher than four percent of oil in the diet can affect the digestibility of the feed. Dr. Dhiman also found that cows fed full fat-extruded soybeans and cottonseed produced almost double the usual amount of CLA. To make the fat or oil easily available to the digestive system Dr. Dhiman has found that roasting and then cracking the seeds helps release the important chemicals.

CLA appears to be very stable, according to Dr. Dhiman. It is not affected by cooking and processing. Dr. Dhiman and Don J. McMahon, professor of Nutrition and Food Science and director of the Western Dairy Research Center at USU, recently prepared cheese using milk from cows fed extruded soybeans and cottonseed. The increased CLA content in the milk was retained in the cheese.

Regular cows' milk available at the grocery store contains an average of 4.5 milligrams of CLA per gram of fat. The lower the fat content of the milk, the less CLA.

General CLA content of various foods (in milligrams per gram of fat)

"Until the results are in, dietary moderation is still the best advice for humans," said Dr. Dhiman. He cautions that people might want to think about the milligrams of CLA they are passing up in their efforts to cut out all the dairy and meat fats from their menus.