Humble Soybean vs. Cancer and Pain
By Sean Henahan, Access Excellence
Anaheim, CA (1/25/99)- The humble soy bean contains potent anti-cancer and anti-pain capabilities, report researchers at the annual meeting of the American Association for the Advancement of Science.
Right: Baked Thai-style Tofu Brochettes
Researchers at Wake Forest University reported the results of series of studies with post-menopausal monkeys. When the monkeys received estrogen replacement therapy, precancerous cell proliferation was observed in mammary glands and in endometrial tissue. This was expected. Then the monkeys were fed a diet including plenty of soy products. The precancerous cell changes stopped shortly thereafter.
"These data indicate that soy supplements may decrease breast and endometrial cell proliferation and therefore could decrease cancer risk in these tissues," reported J. Mark Cline, D.V.M., Ph.D., assistant professor of comparative medicine, Wake Forest University.
Cline believes that the the soy protein mimics the action of progestin, which also slows cellular proliferation and is known to reduce cancer risk. he emphasized that much research remains to be done to better understand how soy protein, which contains plant estrogens called phytoestrogens, exerts these actions.
It is likely that the amount of phytoestrogens is important for the overall effect. In another study involving rats whose ovaries had been removed, the soy proteins did not cause an increase in cell proliferation either in the uterus or mammary gland tissues. However, when the animals received low doses of estrogen replacement therapy, the soy estrogen appeared to cause an increase in cell proliferation in breast tissue. Yet at a higher dose of estrogen replacement therapy, the soy diminished the cell proliferation in both the uterus and breast.
"At some dose combinations, the two are additive, and at other dose combinations, they are antagonistic. Widespread consumption of phytochemicals in the human diet and as supplements make it imperative that we understand their effects, particularly as they related to differing developmental and functional stages of the breast," Cline said.
Studies of human populations show a lower incidence of breast cancer in Asia, where diets contain higher amounts of soy protein. Recent studies have shown that American-born children of Asian immigrants have a 60 percent higher risk of developing breast cancer than do native Asians who immigrate to America.
"This implies that the breast-cancer protective effect may occur early in life. The benefit of soy phytoestrogens is clearer for dietary exposures early in life and for pre-menopausal women. The benefit for older women and breast cancer survivors remains to be determined," he said.
Pain Relief
In a recent issue of the journal Neuroscience Letters, researchers at Johns Hopkins University reported that laboratory rats fed a diet high in soy protein develop far less pain after nerve injury than their counterparts on soy-free diets.
"In people, strong individual differences exist in the perception of pain. And while this is undoubtedly due to a number of factors, the idea that diet could affect the pain experience offers fascinating possibilities for understanding our vulnerability to it. Similarities do exist between rats and humans in the biology of pain perception," says Hopkins neurosurgeon James N. Campbell, M.D.
The finding came about accidentally. The researchers were developing an animal model of a phenomenon seen in humans, where pain sensitivity increases following nerve injury. Conflicting results with colleagues in Israel led the investigators to check every aspect of the protocol. Finally, they realized that the only difference had been what was in the food bowl.
It turned out that the rat chow used in the American side of the protocol had a lot more soy protein than the Israeli chow. When the American rats were fed the soy-free diet, their sensitivity to pain also returned.
The next step will be for the researchers to investigate which component of soy meal suppresses sensitivity, and how it does this. That research could help explain individual differences in pain sensitivity, and might lead to new therapies, said Campbell.
Copyright 1999© Info
Ginkgo Extracts Show Promise
By Sean Henahan, Access Excellence
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Washington, DC (October 22, 1997)- An extract of the plant Ginkgo biloba, long used in Chinese medicine, appears to provide some benefit for some patients with Alzheimer's disease, reported clinical researchers at the American Medical Association's 16th Annual Science Reporters Conference.
Researchers from the New York Institute for Medical Research, Tarrytown, N.Y., compared the effects of EGb 761, a particular extract of Ginkgo biloba, and and placebo in a year-long, double-blind study of 309 demented patients with mild to moderately severe cognitive impairment caused by Alzheimer disease, vascular dementia or a combination of the two.
The results indicated that EGb had a measurable effect on cognitive impairment and daily living and social behavior in patients with dementia. Although the treatment effect could not be detected by the clinician's global impression of change, it was demonstrated through objective tests of cognitive performance and was strong enough to be noticed by caregivers.
A little more than one quarter of patients treated for at least six months with EGb achieved at least a four point improvement on the commonly used 70 point Alzheimer Disease Assessment Scale-Cognitive subscale, compared with 14 percent taking placebo. Another rating scale, the Geriatric Evaluation by Relative's Rating Instrument (GERRI), showed improvement in daily living and social behavior of 37 percent of the patients taking EGb, compared with 23 percent taking placebo.
"Compared with the placebo group, the EGb group included twice as many patients whose cognitive performance improved and half as many whose social functioning worsened. In clinical terms, improvement on the ADAS-Cog of four points may be equivalent to a six-month delay in the progression of the disease. EGb appears to stabilize and, in an additional 20 percent of cases (vs. placebo), improve the patient's functioning for periods of six months to one year. Regarding its safety, adverse events associated with EGb were no different from those associated with placebo," reported Pierre L. LeBars, M.D., Ph.D.
"Although it has a reasonably modest effect, it could be meaningful to caregivers. To have a plateau for six months and be able to interact with the person when they're still at a relatively early stage is something that many families would appreciate, I think," Marcelle Morrison-Bogorad, an Alzheimer's disease researcher at the National Institute on Aging at the National Institutes of Health, told the press.
Extracts from the Ginkgo biloba tree have long been used in China for diseases associated with old age. The extract of Ginkgo biloba used in this study , EGb 761, has recently been approved in Germany for the treatment of dementia.
The researchers do not know how EGb exerts its neurological effects. Ginkgo extracts contain antioxidants that may help to protect cells against oxidative damage. Oxidative damage has been seen in the brain cells of Alzheimer's patients. Ginkgo extracts also contains compounds that act as vasodilators, increasing blood flow. They also contain substances which exert strong anti-platelet effects.
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