Friday, June 1, 2001 - Study: Fish might cut prostate cancer risk
Swedish researchers suggest fatty acids could reduce danger to men by half
Associated Press
Eating even moderate amounts of oily fish such as mackerel, salmon and
sardines might cut the risk of prostate cancer in half, new Swedish
research suggests.
Omega-3 fatty acids, plentiful in dark, oily fish, are known to fight heart
disease. They also have shown promise in protecting against cancers of
the colon, rectum and ovary.
Previous studies have shown fatty fish oils can impede the growth of
prostate cancer cells in laboratory dishes and in animals. In another
study, prostate cancer was found less frequently in men who had high
levels of fatty acids in their blood.
Now, a new study, published this week in The Lancet, a British medical
journal, found that Swedish men who ate greasy fish only occasionally
or not at all were twice as likely to develop prostate cancer as those who
made it a moderate or large part of their diet.
Dr. Regina G. Ziegler, a nutritional epidemiologist at the National Cancer
Institute, was cautious about the Swedish findings. The study was
financed by the Swedish Cancer Society, The John D. and Catherine T.
MacArthur Foundation and the Swedish Council for Planning and
Coordination of Research.
"It's a provocative study," said Dr. Ziegler, who was not involved with
the research. "But there could be other dietary patterns that go along
with eating very little fish that could be at work here."
People who seldom or never eat fish tend to substitute with more red
meat, Dr. Ziegler said, and scientists believe animal fat – butter, cream,
beef, pork and processed meats – may encourage prostate cancer.
"Is the fish really protective, or is red meat causing the cancer?" Dr.
Ziegler cautioned.
Also, Swedish men eat a lot of oily fish, so there weren't many in the
group who ate very little of it. That means that although the study
involved thousands of men, the effect seen was driven by a small
number of men with unusual eating habits. With such a small sample, it
is difficult to rule out the possibility that it was not the fish itself, but
something else about the men who were not big fish eaters, Dr. Ziegler
said.
Prostate cancer strikes about 21 out of every 100,000 men worldwide,
according to the World Health Organization. It is most common in North
America and northwestern Europe.
The study involved 6,272 men followed for about 30 years. During the
study, 466 of them were diagnosed with prostate cancer, on average
when they were 76 years old.
The link between the fatty fish and a reduced frequency of prostate
cancer was even stronger after the results were adjusted to account for
the influence of other eating habits, a genetic predisposition to prostate
cancer and smoking, drinking and exercise habits, the study said.
"We're only talking about a moderate intake. This would be about two
or maybe three servings a week. That is very manageable," said one of
the researchers, Alicja Wolk, professor of epidemiology and nutrition at
the Karolinska Institute in Stockholm, Sweden. "What is also important
is that the fattier the fish it is, the less you have to eat to get the same
benefit."
Sardines have the most omega-3 oil in them, while the concentration in
tuna is quite a lot less, Dr. Wolk said, adding that it doesn't matter if the
fish is canned. |
