|LE Magazine February 2002|
Selenium supplements may reduce risk of prostate cancer
Research has drawn a connection between low blood levels of selenium and prostate cancer. While the exact mechanism and proper doses are still to be ironed out in further studies, findings to date are encouraging. The latest come from a Stanford University study [Brooks JD, et al. J Urol 2001 Dec;166(6):2034-8], which found that low serum levels of selenium confer a four- to five-fold increased risk of prostate cancer. The study included 52 men with prostate cancer and 96 age-matched controls. What makes these findings compelling is that, for the first time, researchers have established that blood selenium levels decrease with age. Moreover, they discovered a direct link between the risk of prostate cancer and selenium levels in older men, demonstrating that those with higher levels of selenium were at lower risk.
An earlier study by University of Arizona researchers similarly showed that selenium treatment significantly reduced prostate cancer incidence by 63% [Clark LC, et al. Br J Urol 1998 May;81(5):730-4]. After treating 974 men with 200 micrograms of selenium or a placebo and following them for 6.5 years, results revealed 13 prostate cancer cases in the selenium-treated group and 35 cases in the placebo group. Another study reported that supplementing with 200 micrograms of selenium daily reduced men’s risk of developing prostate cancer three-fold, compared to a placebo group whose normal dietary intake was estimated to be about 90 micrograms/day [Giovannucci, E, et al. The Lancet 1998 Sep 5;352:755-56]. A large study is currently underway at Stanford and a number of US research sites to assess whether selenium supplements can lower prostate cancer rates.
Researchers explore DHEA for postmenopausal health
The importance of DHEA (dehydroepiandrosterone), a precursor of estrogen and testosterone, in psychological and sexual health has been underlined in a number of studies. For example, a German study found that DHEA-deficient women supplementing with 50 milligrams DHEA daily for four months had decreased symptoms of depression and anxiety, and improved libido [Wiebke A, et al. NEJM 1999 Sep 30 341(14):1013-1020].
A new study by an Italian team of investigators now suggests that DHEA may be an effective option for preserving health in postmenopausal women. The study [Genazzani AD, et al. Fertil Steril 2001 Aug;76(2):241-8] concluded that oral administration of 50 milligrams of DHEA daily for six months mimics the benefits of traditional HRT (hormone replacement therapy), namely estrogen- progestin in terms of its effects on the GHRH-GH-IGF-1 (growth hormone-releasing hormone-growth hormone) axis. The axis oversees the control of several endocrine functions, including the stimulation of osteoblasts (bone cells) to stimulate skeletal growth in children and maintain bone integrity in adults. During menopause, however, the drop in estrogenic activity reduces the secretion of the hormones of this axis and slowly the bone reduces the amount of calcium, and osteoporosis starts.
The study involved 31 postmenopausal women, who were divided according to their age into two groups (50 to 55 and 60 to 65 years). They were tested for hormonal levels at three and then six months of therapy, and were subjected to a GHRH test before and after the study. Researchers measured the effects of DHEA through ultrasound and bone mass density (BMD) examinations before and after the study. Results showed that the levels of all DHEA-derived steroids and osteocalcin, as well as GH and IGF-1, were increased in plasma under DHEA supplementation.
Lead author, Alessandro Genazzani, M.D., Ph.D., at the University of Modena, says that, “DHEA can be considered a possible replacement therapy since it has a lot of beneficial effects on brain as well as on the neuroendocrine functions in postmenopausal women, [as it] induces the production of allopregnanolone, the most potent endogenous anxiolitic (anxiety-relieving) compound.” Further research will be required to firmly establish the use of DHEA as HRT.
New light on how ibuprofen protects against Alzheimer's disease
The discovery that ibuprofen and a few other non-steroid anti-inflammatory drugs (NSAIDS) reduced the risk of developing Alzheimer’s disease was a major breakthrough. Scientists assumed that this risk reduction was due to the anti-inflammatory action of ibuprofen, chiefly its inhibition of the enzymes called cyclooxygenases (COX), known to be involved in the inflammatory response. But a new study done jointly at the University of California, San Diego School of Medicine and the Mayo Clinic in Jacksonville, Florida, suggests that the mechanism may involve ibuprofen’s ability to reduce the levels of a protein called amyloid-beta 42. Amyloid-beta 42 is involved in forming deposits of harmful plaque in the neurons. The accumulation of this plaque increases the levels of free radicals, impairs neural cell function, and eventually induces cell death.
Using animal and in vitro studies, Dr. Edward Koo, a neurologist at the University of California, San Diego, and his colleagues discovered that certain NSAIDS such as ibuprofen help protect against the development of Alzheimer’s disease by decreasing the levels of amyloid-beta 42 rather than by inhibiting COX enzymes. Indomethacin and sulindac were also effective. These NSAIDS were able to reduce amyloid-beta 42 by 50% to 80%—but only when high doses were used, such as the equivalent of 16 Advil tablets per day. Aspirin did not affect the levels of amyloid-beta 42. Naproxen and celeloxib (Celebrex), a selective COX-2 inhibitor, were likewise ineffective.
A separate in-vitro experiment using cells genetically modified to lack the COX enzymes showed that the lowering of amyloid-beta 42 levels by certain NSAIDS did not depend on inhibiting COX.
Because in some people NSAIDS can have serious side effects including ulcers, Koo has stated that we need to seek new drugs targeting amyloid-beta 42. Such drugs would be effective at reducing the amount of amyloid-beta 42, but would have no COX inhibiting activity. Do note, however, that previous studies have shown that taking as little as four Advil tablets (800 mg of ibuprofen) per day reduces the risk of contracting Alzheimer’s without serious side effects. In fact, in one study, anti-inflammatory drugs slashed the incidence of Alzheimer’s by 75%. To learn more refer back to “Ibuprofen—Over-The-Counter Drug Is Treatment For Alzheimer’s” (Life Extension magazine, November 2000, p. 50).
Rainey P. Scientists learn how painkillers cut Alzheimer’s risk. Reuters, 11-7-2001.
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