Fish oils have received much attention from scientists in the past two decades. However, for all their known benefits, a University of Missouri-Columbia researcher recommends that those with weakened immune systems should avoid large doses of fish oil.

http://www.newswise.com/articles/2001/9/FISHOIL2.UMC.html

University of Missouri, Columbia
21-Sep-01

MU RESEARCHER CAUTIONS AGAINST HIGH DOSES OF FISH OIL SUPPLEMENTS
Large Amounts Might Compromise Disease Resistance

COLUMBIA, Mo. -- Known as a cholesterol reducer and a protective agent for the heart, Omega-3 fatty acids -- also known as fish oils -- have received much attention from scientists in the past two decades. However, for all their benefits, a University of Missouri-Columbia researcher recommends that those with weakened immune systems should avoid large doses of fish oil.

"When the benefits of fish oil were first recognized, they were thought to be a 'magic bullet,'" said Kevin Fritsche, associate professor of animal and nutritional sciences. "However, the influence Omega-3 fatty acids have on immune cell function indicates that under some circumstances, disease resistance is impaired."

Fritsche has studied Omega-3 fatty acids since 1982. Interest in the oils began after researchers discovered that Greenland Eskimos had a low incidence of death caused by cardiovascular diseases, despite the fact that their diet of marine fish was high in fat and cholesterol. Soon after this finding, other health benefits started to be uncovered.

"Among the benefits researchers found was that, in large amounts, Omega-3s had an anti-inflammatory effect," he said. "While this in itself can be beneficial to those suffering from inflammatory diseases such as arthritis, our research indicates that those with weakened immune systems, such as the elderly, could be at risk if they are taking large amounts of fish oil for therapeutic reasons."

Fritsche explained that inflammation plays a key role in the body's defense against infection. It acts like an alarm, notifying the immune system that an infectious agent, such as bacteria, has been detected. In addition, inflammation is designed to help slow the spread of the infection through the body.

In his research, Fritsche studied how mice responded to bacterial infection after being fed diets containing varied levels of two specific Omega-3 fatty acids. He found that mice fed diets containing fish oils responded slower to infection and were more likely to die from the infection than mice fed diets containing no fish oil.

"It appears fish oil causes a decrease in the production of a molecule that helps to shape the immune response, but we don't know what the long-term consequences are to the immune system," he said. "Our goal now is to determine why and how this impairment of the immune system occurs. If we can figure out the mechanisms behind it, we might be able to prevent it."

Contact: Jason L. Jenkins
Senior Information Specialist
(573) 882-6217
JenkinsJL@missouri.edu
 

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