by Suzi Fraser
04/05/2006
At a time when one man in six will be diagnosed with prostate cancer during
his lifetime, there is encouraging news: new research shows that men may
keep this disease from spreading by consuming fatty fish, such as canned
tuna, that are rich in essential omega-3 fatty acids.
Published in the March issue of the British Journal of Cancer, the study
was conducted by scientists at the Paterson Institute at the Christie
Hospital in Manchester, England and finds that the omega-3 fatty acids in
fish are able to block the spread of cancerous cells in the prostate gland.
This makes it possible to confine the cancer to the prostate where
treatment with surgery or radiotherapy is very effective. According to the
American Cancer Society, the 5-year relative survival rate for men whose
prostate cancer remains localized is nearly 100 percent.
The new study also examines why omega-3 fatty acids are protective,
suggesting they may block the action of a common fatty acid in prostate
cells called arachidonic acid, which has been found to increase the spread
of tumor cells into the bone marrow. For this reason, the researchers
advocate adding more omega-3 fatty acids to the diet to balance the amount
of arachidonic acid converted in the body from consumption of vegetable
oils. Because Americans eat little fish, they often lack the omega-3s that
restrain the effects of arachidonic acid.
The British study adds to a growing body of research linking two of the
omega-3 fatty acids found in fatty fish -- DHA (docosahexaenoic acid) and
EPA (eicosapentaenoic acid) -- with a lower risk of breast, colon and
prostate cancers. This includes a major study of more than 35,000 women by
the National University of Singapore whose increased consumption of DHA and
EPA lowered the risk of developing breast cancer by 26 percent.
Of the top 10 most commonly consumed fish in the U.S., salmon and canned
albacore tuna have the highest levels of the omega-3 fatty acid DHA,
according to the U.S. Department of Agriculture (USDA) Nutrition Database.
Besides having a protective effect against certain cancers, omega-3 fatty
acids lower the risk of heart disease and stroke and reduce the symptoms of
some inflammatory conditions such as rheumatoid arthritis. Promising
research also suggests these fatty acids may reduce the chance of
Alzheimer's disease and maintain good cognitive function - especially as
people age.