Lijnzaad en ginseng bij kanker.*
Uit twee Amerikaanse studies blijkt dat lijnzaad goed kan werken bij kanker en ginseng de moeheid bij kanker duidelijk kan verminderen. In de lijnzaadstudie kregen de helft van 161 mannen met prostaatkanker 30 dagen lang dagelijks 30 gram lijnzaad voordat ze geopereerd werden. Nadat iedereen geopereerd was bleek dat de kankercellen van de mannen in de lijnzaadgroep wel 30-40% minder gegroeid waren. Of lijnzaad ook prostaatkanker kan voorkomen zal in nieuwe studies nog onderzocht moeten worden.
Uit een kleine ginsengstudie blijkt dat dagelijks voldoende ginseng, minimaal 1.000 mg/dag bij meer dan een kwart van kankerpatiënten een duidelijk tot veel beter effect heeft op vermoeidheidverschijnselen.
Flaxseed,
ginseng show benefit in cancer treatment
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Flaxseed slowed the growth of prostate tumors in men, while ginseng helped
relieve the fatigue that cancer patients often feel, U.S. researchers reported
on Saturday in two of the first scientifically rigorous looks at alternative
medicine.
The
studies reflect doctors' efforts to explore the risks and benefits of foods and
supplements routinely taken by their patients but without any scientific
evidence of any benefit.
Americans
spend between $36 billion and $47 billion a year on complementary and
alternative therapies, according to the National Center for Health Statistics.
"Patients
are taking these compounds but we need to know if they are doing any good or any
harm," said Dr. Bruce Cheson of Georgetown University Hospital in
Washington, who led a panel on alternative therapies at a meeting of the
American Society of Clinical Oncology.
In
the flaxseed study, researchers at Duke University Medical Center in North
Carolina and colleagues evaluated the seed's role as a food supplement in 161
men who were scheduled to undergo surgery for prostate cancer.
"The
growth rate was decreased in the men who got flaxseed," said Dr. Nancy
Davidson, an oncologist at Johns Hopkins University in Baltimore who is
president-elect of ASCO. "I think this is fascinating."
Flaxseed
is rich in omega-3 fatty acids and lignans, a fiber found on the seed coat.
"We
were looking at flaxseed because of its unique nutrient profile," said
Wendy Demark-Wahnefried, a researcher in Duke's School of Nursing, who led the
study.
Half
of the men in the study added 30 grams of flaxseed daily to their diets for
about 30 days. Half of the flaxseed group also went on a low-fat diet.
After
the surgery, the researchers looked at the men's tumor cells to see how quickly
the cancer had multiplied.
The
cancer cells in both the flaxseed groups grew about 30 to 40 percent slower than
the control group.
But
Demark-Wahnefried is not ready to prescribe flaxseed.
"It's
a healthy food. It has a lot of vitamins and a lot of fiber. But we can not
definitively say at this point you should take flaxseed because it is protective
against prostate cancer," she said, adding that flaxseed now needed to be
studied to see if it can prevent prostate cancer.
In
the ginseng trial, Debra Barton of the Mayo Clinic in Rochester, Minnesota, and
colleagues tested three different doses of the herb on patients with a variety
of cancers who were expected to live at least six months.
Twenty-five
percent of patients taking a 1,000-mg dose and 27 percent of patients taking a
2,000-mg dose said their fatigue symptoms were "moderately better" or
"much better."
Only
10 percent of those taking a 750-mg dose reported an improvement, which was
about the same as the placebo group.
Patients
in the trial took Wisconsin ginseng from a single crop that was tested for
uniform potency. It was powdered and given in a capsule form.
"I
wouldn't have predicted this, I have to admit," Davidson said in an
interview. "We might want to test this on a large scale."
The flaxseed study was funded by the National Institutes of Health and the ginseng study was supported by U.S. Public Health Service grants. (Juni 2007)