Fish story or fact?

The notion that eating fish is healthy is being challenged in a new study authored by a University of Hawai'i researcher and a part-time Big Island resident.

The work by Claudio Nigg, a researcher with the university's John A. Burns School of Medicine, and retired physician David Cundiff, found a link between people who eat more fish and who led healthier lifestyles. But it couldn't definitively say eating fish lowered heart disease risk.

Instead, it found that people who eat fish regularly are more likely have better diets, smoke less and exercise more.

"Fish may be an indicator of a healthier lifestyle or eating habits," said Nigg, a researcher with the medical school's Department of Public Health Services.

"But it certainly doesn't say that it's fish that's the healthy piece of it."

Nigg said people who consume lots of fish generally eat more fruits and vegetables and have diets with higher fiber content compared to their red-meat-eating counterparts.

He said fish is usually accompanied by a vegetable when ordered in a restaurant, whereas a hamburger tends to arrive with french fries.

Nigg said he was brought into the study by Cundiff, who needed help assessing data in looking at the health benefits of eating fish. Many seafood promoters note some fish are high in omega-3 fatty acids and therefore are a healthy menu choice. The American Heart Association also recommends eating fish at least two times a week because omega-3 fatty acids can reduce risk of heart disease.

Nigg, Cundiff and fellow study author Amy Lanou of the University of North Carolina, noted the Institute of Medicine's food and nutrition committee in October declared a preliminary finding between eating fish and lowering heart disease risk but that the committee said it wasn't certain whether the benefit came from the protective effects of omega-3 or the fact that people weren't eating fattening cuts of meat when they opted for seafood.

"It could be that it's just an indicator of a healthy diet and the healthy diet may be the cause for the long-term health benefits," Nigg said.

To show the link, a study needs to be done where participants are on a controlled diet with some eating fish and others having meat, he said.

Cundiff, Nigg and Lanou didn't test for these effects with their study.

Instead they reviewed dietary data from 1,441 people over a nine-year period. What they found was people who ate a lot of fish tended to eat less, ingest less fat and saturated fat and exercise more.

Those people who ate more red meat ate more saturated fat, exercised less and smoked more.

Nigg said he expected the study will have its share of detractors because of the questions it raises. But he said it may result in more scientific work into the links between fish consumption and lower heart disease risk.

"This will definitely increase the discussion about things," Nigg said. "If we spur some people to discuss things, then we're happy."

Reach Greg Wiles at gwiles@honoluluadvertiser.com.