However, experts caution that the findings are preliminary and do not mean patients should start stocking up on the products.

"They should not substitute but complement standard cancer care," said Bruce D. Cheson, head of hematology at the Lombardi Comprehensive Cancer Center and Georgetown University Hospital. He was not involved in the studies.

On Saturday, researchers released data showing that patients taking Wisconsin ginseng reported less fatigue than those not taking the supplement. There were three different doses given to the nearly 300 patients, and those taking the most ginseng -- 1,000mg a day and 2,000mg a day -- saw the greatest benefit, said presenter Debra Barton, an associate professor of oncology at the Mayo Clinic.

"We're not recommending this," she said, adding that more studies need to be conducted. Until this happens, patients should continue to use the only proven non-drug-related treatment for fatigue, which is exercise, she said.

Ginseng has also been touted to help a variety of other conditions such as depression and anxiety, erectile dysfunction and aging. It is also believed to protect the heart, strengthen digestive functions, and stabilize blood pressure and insulin levels.

However, the American Cancer Society says that consumers should be cautious when taking ginseng because it can cause undesirable side effects in high doses and may even be dangerous when taken with certain medicines, as well as when undergoing surgery.

The research was presented at the American Society of Clinical Oncology meeting.

Meanwhile, combining flaxseed with a low-fat diet appears to slow the growth of tumors in patients with prostate cancer.

The supplement is a rich source of lignans, which may play a role in preventing estrogen-dependent cancers, such as breast cancer. Lignans may also function as antioxidants and may slow cell growth.

Flaxseed is also high in alpha-linolenic acid, an omega-3 fatty acid, which is thought to have beneficial effects against cancer.

For the study, more than 160 prostate cancer patients were randomly assigned to take flaxseed or maintain a low-fat diet either alone or in combination prior to surgery to treat their disease.

The researchers found that those men on the low-fat diet and taking flaxseed (30mg per day) had a significantly lower cell growth rate in their tumors.

Paul Hutson, an associate professor of pharmacy at the University of Wisconsin Carbone Cancer Center, said the good thing is that neither ginseng nor flaxseed caused harm. But while the supplements did make people feel better, it did not translate into a survival benefit for patients with prostate cancer, he said.

However, not all the news was good for complementary approaches for cancer treatment.

Charles Lu, an associate professor of thoracic and head and neck oncology at the University of Texas M.D. Anderson Cancer Center, presented findings showing that shark cartilage extract does not improve survival in patients with non-small-cell lung cancer.

"Our patients are taking these complementary approaches, and we need to know whether they are doing any good or whether they are doing harm," Cheson said.

From the June 18, 2007, Prepared Foods e-Flash