June 6, 2007  Mixed Results For Some Natural Products in Cancer Trials

Some bad news and good news reported in the last week from the world of natural products therapeutics.  First, the bad news.  Shark cartilage extract showed no benefits in a study with advanced lung cancer patients.  Because shark cartilage doesn’t have blood vessels, some researchers theorized that the substance probably contains a blood vessel growth inhibitor, which might help starve tumors of nutrients.  But results presented at the annual meeting of the American Society of Clinical Oncology found the shark cartilage to be of no help.

Now some better news.  Another study reported at the meeting found that American ginseng helped cancer patients who suffer from extreme fatigue.  And the amount of fatigue relief was dose dependent, a good sign that it wasn’t just a placebo effect.  An upcoming trial will try to establish an exact dosage.

Finally, an NIH-funded study reported at the oncology meeting found that dietary flaxseed was effective in stopping the growth of prostate tumors.  Flaxseed is rich in omega-3 fatty acids, which may effect how cancer cells attach to other cells.  Flaxseed also contains lignans, which may interfere with the tumor’s blood vessel growth.