Chicago – The first scientific tests of some popular alternative-medicine products hint that American ginseng might lessen cancer fatigue and that flaxseed might slow the growth of prostate tumors.
But a big study proved shark cartilage worthless against lung cancer, and doctors said people should not take it.
The research was reported Saturday at an American Society of Clinical Oncology conference.
The ginseng and flaxseed studies are small and preliminary, and specialists warned against making too much of them because the substances tested are not the same as what consumers find on store shelves.
But the results suggest that some herbal remedies eventually may find niches for treating specific cancers, symptoms or side effects.
Americans spend millions on these products, which are not approved by the federal Food and Drug Administration, even though no good studies confirm the benefits they tout.
Some “natural” remedies such as laetrile or high doses of vitamin C proved not helpful and even harmful for cancer patients once they were scientifically studied, noted Dr. Bruce Cheson, a cancer specialist at Georgetown University Hospital. Some keep chemotherapy from working as it should.
“Just because it is a vitamin or a leafy green does not ensure it does not have some harmful effects,” Cheson said.
Herbal products vary widely in their purity and the amount and type of active ingredients. The new federally funded studies used standardized compounds so they could say with some certainty whether they have any effect.
Debra Barton, a research nurse at the Mayo Clinic in Rochester, Minn., tested powdered, 4-year-old Wisconsin ginseng root, which is different from Asian ginseng and other varieties commonly sold, to treat the extreme tiredness that most people suffer from cancer or its treatment.
She randomly assigned 282 people with breast, lung, colon and other forms of cancer to take either 750, 1,000 or 2,000 milligrams of ginseng or dummy capsules daily for eight weeks.
One-fourth of those on higher doses said their fatigue was moderately or much better, compared with only 10 percent of those on a low dose or dummy pills.
Results are promising, but it is too soon to recommend that people use ginseng, Barton said. A better idea is exercise – the one treatment already shown to help cancer fatigue, she said.
In the flaxseed study, four groups of about 40 men who were scheduled to have their prostates removed three weeks later were assigned to get either 30 grams of powdered flaxseed, a low-fat diet, both or neither until their surgery.
After the prostates were removed from the men in the study group, researchers found that tumors had been growing 30 percent to 40 percent slower in two groups taking flaxseed, based on how quickly cells were multiplying.
“Our findings are compelling, but they’re preliminary,” cautioned Wendy Demark- Wahnefried of Duke University Medical Center, who led the study.
