Cornell University researchers are trying to boost the level of a fatty acid in milk shown to prevent or limit cancer, bolstering milk's health benefits and giving struggling farmers a new market.
Dale Bauman, a professor of food science at Cornell, is heading the research to formulate a diet for dairy cows that will increase a type of conjugated linoleic acid, or CLA, in the milk they produce.
Studies in cell lines and animal models have shown CLA to be effective at preventing the formation of tumors. The fatty acid appears to block angiogenesis, the process by which a tumor creates new blood vessels, said Dr. James Marshall, director of the prevention program at Roswell Park Cancer Institute in Buffalo. Without creating new blood vessels, a tumor's growth stops because it cannot get nutrients or oxygen.
In the next few months, about 80 of the dairy 1,500 cows at Spruce Haven Farm in Union Springs will be given the special diet.
"We've been tracking the scientific info for about five years," said Doug Young, a partner in the operation. "We think it has great potential for dairy farmers to add value to their product and add revenue over time."
Dr. Margot Ip, a researcher at Roswell Park, said research has also shown CLA can destroy cancerous cells. There haven't yet been any studies looking at CLA's effect on human cancer. However, it is being tested in humans for its ability to modify blood lipid profiles, body composition and immune function.
Most of Roswell Park's work with CLA has focused on breast cancer. Since the fat cells in a human breast can accumulate CLA, the fatty acid may be effective in stopping breast cancer tumors, Ip said. Other research has also shown it to be effective in blocking skin cancer.
CLA is a byproduct of metabolism that occurs in the cow's first stomach, or rumen. Bacteria acting on foods containing linolenic and linoleic acid - such as corn and soybeans - convert those fatty acids.
Young's business, part of a group of farms, hopes to eventually find a processor to develop the high-CLA milk.
While milk prices have risen over the past several months, dairy has proved a hard existence in recent years with many dairy farmers unable to recoup their costs.
New York dairy production in December fell 1.3 percent to 959 million pounds of milk from a year earlier, according to the New York Agricultural Statistics Service. The number of milk cows totaled 646,000 head, down 11,000 from December of the previous year.
"Something like 5 to 10 percent of dairy farmers exit the business every year," Young said.
Dairy is the biggest part of New York's agricultural industry, accounting for $1.56 billion in revenue last year. The state ranks No. 3 in the country in milk production, after Wisconsin and California. In 2003, U.S. dairy farms produced 170.3 million pounds of milk, according to the Department of Agriculture.
Researchers say many more questions will need to be answered on CLA's benefits before the medical community is sold on the idea.
"The CLA story is really quite preliminary," Marshall said. "We really need to collect additional data."
By Mark Johnson