![]()
2007/06/21
Based on earlier reporting by Health Day News
Early study with mice suggests a potentially beneficial effect
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.
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 heart disease and even 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.
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, or apoptosis.
"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.
The study is published in the June 21 online edition of the Journal of Clinical Investigation.
Chen said it's important that consumers realize that not all omega-3s are created equal in terms of their potential health benefits.
"In this study, we are only referring to the long-chain form" found in oily fish, such as mackerel, herring, albacore tuna and salmon, he said. Other, shorter-chain varieties can be found in flaxseed and plant sources, but their impact, if any, on cancer is even less clear.
"We are doing a type of study right now to see whether there is any difference," Chen said.