Fish oil may increase effectiveness of chemotherapy, lessen side effects

American Institute for Cancer Research
Wednesday, 21 July 1999

New evidence suggests that by consuming more of certain polyunsaturated fatty acids - the kind found in fish oil - cancer patients can help chemotherapy drugs selectively destroy cancerous cells with less damage to the body's normal cells. Scientists sponsored by the American Institute for Cancer Research (AICR) are investigating an innovative technique that may increase the effectiveness of chemotherapy while reducing its destructive side effects.

Cancer therapies make use of the biochemical differences that exist between cancerous cells and normal cells, according to AICR scientists. Unfortunately, these differences are often too subtle for the drugs used in conventional chemotherapy to utilize effectively.

Drs. Elaine Hardman and Ivan Cameron, researchers at the University of Texas Health Science Center, are investigating a new method of attack. Funded by an AICR grant, they have discovered evidence that normal and cancerous cells differ in a promising - and heretofore unexamined - way.

"The polyunsaturated fatty acids found in fish oil are used by both normal cells and cancerous cells in making up their cell membranes," says Dr. Hardman, the study's principal investigator. "Studies suggest that the more types of these fatty acids the cancer cells incorporate, the more sensitive they become to damage by certain chemotherapeutic drugs. Left unchecked, this damage can initiate a chain reaction that ultimately kills the cancer cell."

In research trials, healthy cells were capable of neutralizing this damage; cancerous cells were not. As a result, cancerous tumors showed significant regressions, while normal cells showed little evidence of damage, if any at all.

"These findings are very promising," says Ritva Butrum, AICR's Vice President of Research. "It may soon be possible for cancer patients to dramatically increase the effectiveness of their chemotherapy simply by making a few dietary adjustments. Such a direct and non-invasive way to augment current treatment is sorely needed, and would represent a great leap forward."

Recent estimates link chemotherapy treatment to the remission of over 138,000 cancer cases each year in America alone. In many other cases, however, prolonged and debilitating side effects cause treatment to be halted before it can complete its work.

The most widely used form of chemotherapy in current use, for example, is based on information that has been well-established: many cancer cells multiply faster than normal cells. Drugs are introduced into the body that slow such rapid proliferation.

But these drugs, say AICR researchers, can also interfere with the many normal cell populations that multiply quickly, causing considerable damage to the body. Many treatments harm the lining of the intestine to such a degree that severe diarrhea results.

Other common side effects of treatment range from minor annoyances like dry mouth and sore throat to chronic and life-altering obstacles like fatigue, nausea, vomiting, malnutrition and dangerous weight loss. "Increasing the amount of fish oil in a patient's diet may delay or eliminate such side-effects," says Dr. Hardman, "allowing effective doses of chemotherapeutic drugs to be administered with a greater margin of safety than ever before."

These promising findings add to the growing body of research into the possible health benefits of omega-3 fatty acids. These compounds, best found in such dietary sources as salmon, striped bass, swordfish and tuna, have already been shown to slow or prevent the growth of tumors and are gaining renown for their apparent role in lowering cholesterol and blood pressure.

If fatty fish doesn't appeal, smaller amounts of omega-3 fatty acids are present in flaxseed, canola oil, soybeans and walnuts. Fish oil capsules are an extremely concentrated source of omega-3 fatty acids, and as with any supplement, patients should check with a physician before taking them.

For more information, or to contact American Institute for Cancer Research, see their website at: www.aicr.org