Selenium tegen HIV en voor beter geheugen later.*

Uit twee studies blijken weer eens de goede eigenschappen van het mineraal selenium.

Uit een Chinese studie blijkt dat selenium goed is voor de cognitatieve eigenschappen. Als men in zijn leven zorgt voor voldoende selenium in de voeding dan blijkt uit deze studie dat dat een geestelijk leeftijdsverschil van wel 10 jaar kan betekenen met zij die (te) weinig selenium in hun voeding hadden.

Uit een andere Amerikaanse studie blijkt dat selenium goed werk te doen bij een HIV besmetting. Regelmatig voldoende selenium zorgt voor een daling van het aantal virusdeeltjes en een verhoging van het aantal immuuncellen.  Selenium kan dus een veilig en goed hulpmiddel zijn bij de aanpak van HIV.
"Long-term exposure to selenium may be needed to impact brain function later in life," the study says.
But Gao found the results more empowering than disempowering. "Selenium exposure, unlike other factors studied for Alzheimer's disease, is a factor that is easily modifiable by changing dietary habits or through supplements," he said.
Selenium Level and Cognitive Function in Rural Elderly Chinese

Sujuan Gao¹, Yinlong Jin², Kathleen S. Hall³, Chaoke Liang², Frederick W. Unverzagt³, Rongdi Ji², Jill R. Murrell⁴, Jingxiang Cao², Jianzhao Shen¹, Feng Ma², Janetta Matesan¹, Bo Ying², Yibin Cheng², Jianchao Bian⁵, Ping Li⁶ and Hugh C. Hendrie^3,7,8

¹ Department of Medicine, School of Medicine, Indiana University, Indianapolis, IN
² Institute for Environmental Health and Related Product Safety, Chinese Center for Disease Control and Prevention, Beijing, People's Republic of China
³ Department of Psychiatry, School of Medicine, Indiana University, Indianapolis, IN
⁴ Department of Pathology and Laboratory Medicine, School of Medicine, Indiana University, Indianapolis, IN
⁵ Shandong Institute for Prevention and Treatment of Endemic Disease in China, Jinan, People's Republic of China
⁶ Sichuan Provincial Center for Disease Control and Prevention in China, Chengdu, People's Republic of China
⁷ Center for Aging Research, Indiana University, Indianapolis, IN
⁸ Regenstrief Institute, Inc., Indianapolis, IN

Correspondence to Dr. Sujuan Gao, Department of Medicine, Indiana University School of Medicine, 410 West 10th Street, Suite 3000, Indianapolis, IN 46202-2872 (e-mail: sgao@iupui.edu ).

Selenium is a trace element associated with antioxidant activity and is considered to be a protective agent against free radicals through enhanced enzyme activity. Studies on selenium and cognitive function or Alzheimer's disease have yielded inconsistent results. A cross-sectional survey of 2,000 rural Chinese aged 65 years or older from two provinces in the People's Republic of China was conducted from December 2003 to May 2005 by use of the Community Screening Instrument for Dementia, the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) Word List Learning Test, the Indiana University Story Recall Test, the Animal Fluency Test, and the Indiana University Token Test. Over 70% of the study participants have lived in the same village since birth. Nail samples were collected and analyzed for selenium contents. Analysis-of-covariance models were used to estimate the association between quintile selenium levels measured in nail samples and cognitive test scores, with adjustment for other covariates. Lower selenium levels measured in nail samples were significantly associated with lower cognitive scores (p < 0.0087 for all tests) except the Animal Fluency Test (p = 0.4378). A dose-response effect of selenium quintiles was also seen for those significant associations. Results in this geographically stable cohort support the hypothesis that a lifelong low selenium level is associated with lower cognitive function.

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Mineral shows promise on HIV
Selenium is reported to reduce the amount of virus in patients. It's like 'a lion tamer in a circus,' a study author says.

By Jia-Rui Chong

Giving selenium, an antioxidant mineral sold as a dietary supplement, to HIV patients modestly reduced the amount of virus in their blood, according to a study published Monday.

Patients taking 200 micrograms of high selenium yeast daily saw an average 12% drop in blood virus levels, according to the study in the Archives of Internal Medicine.

"I liken selenium to a lion tamer in a circus," said lead author Barry Hurwitz, a professor of psychology and medicine at the University of Miami. "What it appears to do is make [the virus] more docile, less virulent and less likely to replicate."

But Dr. Jeffrey Lennox, principal investigator for Emory University's HIV Clinical Trials Unit who was not involved in the study, said selenium's effect appears small, less than a variation that can be seen in some AIDS patients from week to week.

He added that taking selenium also did not have wide clinical implications in the U.S. because there are already antiretroviral therapies here that can decrease the amount of virus in the blood to undetectable levels.

"The conclusions are intriguing, but they don't change current medical practice," Lennox said. "In people not receiving optimum therapy, selenium might be a benefit."

Selenium is a trace mineral in soil that can be absorbed by plants. Cows and other animals can also absorb the mineral if they feed on grain grown in soil with selenium.

Research has linked selenium deficiency to forms of heart disease, hypothyroidism and a weakened immune system. Previous studies also have found that the mineral suppresses HIV replication in the lab and that some HIV patients have lower selenium levels.

Hurwitz's study, which was funded by the National Institutes of Health, looked at 174 HIV patients in the Miami area. About two-thirds of the patients were already taking antiretroviral drugs. About a third were not taking any AIDS drugs.

The study found that the 50 people who regularly took their selenium pills saw the virus in their blood drop by about 10,000 viral particles per milliliter of blood after nine months, a mean decrease of about 12%. The number of immune cells, known as T-cells, increased by a mean of about 30 cells per microliter of blood.

Selenium had a good effect at nine months regardless of what kind of drug regimen the patients were on, Hurwitz said.

The 83 patients in the placebo group saw the amount of virus in their blood increase by 10,000 to 20,000 viral particles per milliliter of blood. Their T-cells diminish by about 30 cells per microliter.

Another group of 41 people, classified as "nonresponders" because they did not adhere to their selenium schedule or because gastrointestinal problems prevented them from absorbing selenium, had about the same results as the placebo group.

Hurwitz and his colleagues are still analyzing the data on selenium's effects beyond nine months, but he said the benefits appear to be sustained

Jeffrey Blumberg, a professor of nutrition at Tufts University, said that because selenium appears to help and has no serious side effects, there is no reason not to use it as booster with traditional therapies.

"Selenium is a simple, inexpensive and safe adjunct therapy," said Blumberg, who was not involved in the study. "It's pretty reasonable to go forward with this (Maart 2007) (Opm. Meer over selenium.)