Fish Oil for Prostate Health
A new study with mice suggests that diets high in omega-3 fatty acids from fish might help slow prostate cancer.
The comparable levels of dietary omega-3s used in the study "are much higher than the average Western diet, but they are not unachievable,"
said senior researcher Yong Chen, a professor of cancer biology at Wake Forest University School of Medicine in Winston-Salem, N.C.
Omega-3 fatty acids -- especially the "long-chain" forms found in oily fish -- have become the latest nutrition superstars, with studies
suggesting they can help prevent prostate cancer.
The exact mechanism driving the purported anti-cancer effect is still unclear, Chen said. One leading theory contends that specific cellular
enzymes metabolize omega-3s in ways that retard malignancy.
The exact mechanism driving the purported anti-cancer/prostate health benefits and effects of fish oil is still unclear, Chen said. One
leading theory contends that specific cellular enzymes metabolize omega-3s in ways that retard malignancy.
However, Chen's team is investigating a much lesser-known mechanism.
"It turns out that [long-chain] omega-3 fatty acids might modulate apoptosis -- a form of cell death," he said.
Cancer cells spread in two ways: either they proliferate uncontrollably, or they bypass natural signaling that tells them to commit suicide,
"It turns out that a key molecule -- that happens to be called 'Bad' -- may be involved in this process," Chen said. His team now believes
that long-chain omega-3s interact favorably with Bad to push cancer cells back into a normal apoptosis.
In their study, the researchers fed mice diets high in both omega-3 fatty acid and the less-healthy omega-6 fatty acids. These mice were
genetically engineered to lack the Pten tumor suppressor gene, leaving them highly prone to prostate tumors. Dysfunctional Pten
plays a key role in about one-third of human prostate cancers, so this mouse is a great model for human disease, Chen said.
As expected, mice with functioning Pten did not develop prostate cancer, the researchers said.
On the other hand, rodents whose Pten was switched off typically developed prostate tumors. However, 60 percent of these mice survived
if they were fed a high omega-3 diet, compared to just 10 percent given a low omega-3 diet. None of the mice given the high omega-6 diet
survived, the team noted.
There was another wrinkle to the study. In the past, it has been tough for researchers to tease out the effects of omega-6 and omega-3 fatty
acids, which usually occur together in foods. But Chen's team introduced another gene into the Pten-less mice. This gene caused the mice
to convert omega-6 fatty acids into the omega-3 form, thereby limiting this confounding factor.
"That's really a big strength of this study; nobody had really ever done that before," Chen said.
The study is published June 21 in the online edition of the Journal of Clinical Investigation.
According to Chen, the study suggests that diets high in long-chain omega-3 fatty acids might give men an edge against prostate cancer.