Diets high in omega-3 fatty acids from fish may have the potential to improve prognosis in men who are genetically susceptible to developing prostate cancer
Research in mice suggests that diets high in omega-3
fatty acids from fish may have the potential to improve prognosis in men who are
genetically susceptible to developing prostate cancer, according to an article
in the July 2 issue of the Journal of Clinical Investigation.
“This study clearly shows that diet can tip the balance
toward a good or a bad outcome,” said senior researcher Yong Q. Chen, PhD, from
Wake Forest University School of Medicine. “It’s possible that a change in diet
could mean the difference between dying from the disease and surviving with it.”
In mice that were engineered with a genetic defect that
caused prostate cancer, a diet high in omega-3 fatty acids beginning at birth
reduced tumor growth, slowed disease progression and increased survival.
The goal of the current study was to explore gene-diet
interactions in prostate cancer. The mice were engineered to lack a tumor suppressor
gene and spontaneously developed prostate cancer. This gene (Pten) is absent in
60 to 70 percent of metastatic cancers in humans.
The engineered mice and wild-type mice were fed varying
levels of omega-3 and omega-6 polyunsaturated fatty acids. Many vegetable oils
contain omega-6 fatty acids, whereas. fish such as mackerel, lake trout, herring,
sardines, albacore tuna and salmon are high in omega-3 fatty acids.
The mice were fed either a diet high in omega-3 (ratio
of omega-6 to omega-3 was 1:1) a diet low in omega 3 (ratio omega-6 to omega-3
was 20:1), or a diet high in omega-6 (ratio of omega-6 to omega-3 was 40:1) fatty
acids. The scientists compared survival rates and weighed animals’ prostates to
measure tumor progression.
Mice with the tumor suppressor gene remained free of
tumors and had 100 percent survival regardless of diet. In mice with the gene
defect, survival was 60 percent in animals on the high omega-3 diet, 10 percent
in those on the low omega-3 diet, and 0 percent in those on the high omega-6 diet.
“This suggests that if you have good genes, it may not
matter too much what you eat,” said Chen, a professor of cancer biology. “But
if you have a gene that makes you susceptible to prostate cancer, your diet can
tip the balance. Our data demonstrate the importance of gene-diet interactions,
and that genetic cancer risk can be modified favorable by omega-3 fatty acids.”
Chen noted that the mice got lifetime exposures and that
some people may not be willing to change their diets until they develop cancer.
He hopes to study whether there would be beneficial effects of adding omega-3
fatty acids to the diet after tumors have developed.
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