Could Omega-3s Boost Blood Fat Levels?

Dec. 18 -- THURSDAY, Dec. 17 (HealthDay News) -- In a surprise finding, Canadian researchers report that the immediate effect of the fish oil fatty acids that are good for the heart is a short-term increase in blood fats and the molecules that help them form clots.

"We were surprised to find that the acute response has some potentially negative effects in comparison to what you might expect from chronic, long-term intake," said Lindsay E. Robinson, an associate professor of nutrition at the University of Guelph, and leader of the group reporting the finding in the January issue of the Journal of Nutrition.

However, the study results shouldn't affect the current recommendation for eating more oily fish to get the omega-3 polyunsaturated acids that reduce the risk of blood clots that can cause heart attacks and stroke, Robinson said.

"The recommendation to increase intake is very well-studied, and this doesn't change it," she said.

And the effects were seen in a selected group of middle-aged men with metabolic syndrome, a combination of high blood pressure, obesity and elevated blood fat levels, Robinson noted.

"We don't have any reference to a healthy control group, which the study didn't have," she said. "It's possible that in these individuals, there may be a different response to omega-3 fatty acids."

Still, it does indicate that further study is warranted of the effects of omega-3 fatty acids in the postprandial period, the hours immediately following a meal, Robinson said.

"We spend up to 18 hours a day in the postprandial period," she said.

In the study, eight men had controlled intake of three regimens: high doses of omega-3 fatty acids, low doses of them and just plain water. Robinson and her colleagues measured several blood components involved in clotting, including fats and clotting factors such as plasminogen-activator inhibitor-1 (PAI-1) for the following eight hours.

PAI-1 inhibits the destruction of blood clots, so high levels of it in the blood increase the risk of artery-blocking clots.