Fish Oil and Heart Disease
By Anita Campus

"Fish oil supplements help thwart the loss of muscle mass in dogs suffering from heart disease", according to a study at Tufts Univ. School of Veterinary Medicine.

"We are very excited about these results," said Dr. Lisa M. Freeman, a veterinary nutritionist at Tufts. "My hunch is that a higher dose of fish oil might have even more of an effect, but we need to do more studies in this area."
Dogs with heart disease, like people, experience a phenomenon called cachexia, or loss of muscle mass, that decreases strength and immune function. When ill, the body produces elevated levels of hormone-like substances called cytokines, the major one being tumor necrosis factor, to help fight the offending pathogen.

But at high levels and for prolonged periods, cytokines can suppress appetite and cause a loss of muscle mass.
"People with heart disease have increased levels of cytokines, probably as a compensatory response to the disease, but this eventually can have detrimental effects for the patient," Freeman said.

"We wanted to study this mechanism to determine if it could be managed nutritionally, and it turns out that fish oil does indeed reduce cytokine levels."
Although veterinarians have observed cachexia clinically in their patients for years, the precise mechanism of the condition had not been studied in dogs before.

Freeman, who also is a researcher at the Jean Mayer USDA Human Nutrition Research Center on Aging (HNRCA) at Tufts, conducted the fish oil study in collaboration with colleagues from the veterinary school and the HNRCA.
In the eight-week study, 28 dogs with congestive heart failure caused by dilated cardiomyopathy, a naturally occurring disease that weakens the heart muscle in some middle-age dogs and is generally fatal within four to six months, were divided into two groups. One group was given fish oil, and the other received a placebo. Both groups were also given appropriate medical treatments for their condition.

Fish oil is not a magic bullet for treating canine heart disease, Freeman cautions, but the Tufts researchers found a reduction in cytokine levels and an improvement in muscle mass in these animals.
"But even more exciting was the finding that reductions in cytokine levels were associated with a longer survival time," Freeman said. "We'll need to study this further, certainly, but it looks promising."

The study was funded by the National Institutes of Health, Hills Pet Products, the Mark Morris Institute and the American Society for Parenteral and Enteral Nutrition.
Reprinted with permission of Canine Times,, a publication of CFNA, Inc. 509-332-3956.

Anita Campus