OT: Fish Oil May Not Help Prevent Cancer

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Fish Oil May Not Help Prevent Cancer

 

By LINDSEY TANNER

 

CHICAGO (AP) - Fish oil, seen as beneficial for reducing heart disease

risks, probably doesn't help prevent cancer, according to a review of

studies involving more than 700,000 patients.

 

Researchers examined data from 38 studies that tracked patients for up

to 30 years, and said most showed there is no cancer protection from

omega-3 fatty acids. Although a few studies found some risk reduction

for cancers of the breast, prostate and lung, those studies were

relatively small and not definitive, said Dr. Catherine MacLean, the

lead author and a researcher at the Rand Corp. and Greater Los Angeles

Veterans Affairs Healthcare System.

 

" It doesn't mean that omega-3 fatty acids don't have other health

benefits - it's just that reducing cancer risk isn't one of them, "

MacLean said.

 

However, the review is unlikely to be the last word on the issue. Diet

is known to play a role in cancer and the researchers evaluated

observational studies, which provide mostly circumstantial evidence.

 

The reviewed studies examined the effects of fish oil - in both pill

form and as food - on 11 kinds of cancer, mostly tumors of the breast,

colon, lung or prostate.

 

The 38 studies are too heterogeneous - involving different population

groups and different levels of fish oil consumption - to provide a

definitive conclusion about whether fish oil reduces cancer risks, said

Julie Buring, a chronic disease researcher at Harvard's Brigham and

Women's Hospital, who was not involved in the study.

 

" It doesn't tell us it's unlikely or likely, " Buring said. " What is

supported is that right now we don't know. "

 

The study appears in Wednesday's Journal of the American Medical

Association. It was funded by the government's Agency for Healthcare

Research and Quality.

 

Omega-3 fatty acids are plentiful in darker, oily fish including salmon,

sardines and mackerel. They are mostly thought to help prevent heart

disease, not cancerand American Heart Association guidelines recommend

at least two servings of fish per week to help prevent heart disease.

 

Several studies have suggested that fish oil can improve heart and blood

vessel function and lower levels of blood fats called triglycerides.

 

Some animal studies have suggested that fish oil might also reduce

cancer risks but the evidence in people is less clear. The potential

connection is bolstered by low rates for certain cancers in countries

including Japan, where fish consumption is high.

 

The American Cancer Society recommends fish as a source of protein

partly because it doesn't contain high amounts of saturated fats that

are in red meat and which some scientists think might increase risks for

prostate and colon cancer.

 

Colleen Doyle, the society's nutrition and physical activity director,

said the new study won't " change our bottom-line message about fish. "

 

" Even though fish might not reduce cancer risk, it's still important to

include it in your diet " because heart disease is the nation's leading

killer, Doyle said.

 

On the Net:

 

JAMA: http://http://jama.ama-assn.org

 

AHRQ: http://www.ahrq.gov

 

01/24/06 22:59

 

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