Neither Vitamin E or Selenium Found To Prevent Dementia

MedicalResearch.com Interview with:

Richard J. Kryscio, Ph.D. Statistics and Chair, Biostatistics and Sanders-Brown Center on Aging Sanders-Brown Center on Aging University of Kentucky

Dr. Richard Kryscio

Richard J. Kryscio, Ph.D.
Statistics and Chair, Biostatistics and Sanders-Brown Center on Aging
Sanders-Brown Center on Aging
University of Kentucky 

MedicalResearch.com: What is the background for this study?

Response: At the time the trial was initiated (2002), there was ample evidence that oxidative stress is an important mechanism in brain aging. Research showed that protein oxidation is linked to the brain’s response to the abnormal proteins seen in Alzheimer disease (amyloid beta plaques in particular) leading to inflammation, DNA repair problems, reduced energy production, and other cellular changes that are identified mechanisms in the Alzheimer brain.

Both vitamin E and selenium are antioxidants. Antioxidants, either through food or supplements, are believed to reduce oxidative stress throughout the body. In the brain, they may reduce the formation of amyloid beta plaques, reduce brain inflammation, and improve other brain processes. Studies in humans support these hypotheses. The Rotterdam study in the Netherlands, as an example, showed that initial blood levels of vitamin E could predict dementia risk. Those people with higher vitamin E levels were 25% less likely to develop dementia. Also, selenium deficiency results in cognitive difficulties and several population-based studies have shown an association between selenium level and cognitive decline (lower selenium levels are linked to thinking changes in the elderly).
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Preliminary Study Suggests Low Selenium Levels Contribute To Liver Cancer Risk

MedicalResearch.com Interview with:

Dr. David Hughes Honorary Lecturer, Centre for Systems Medicine RCSI Physiology & Medical Physics Dept Royal College of Surgeons in Ireland Ireland

Dr. David Hughes

Dr. David Hughes
Honorary Lecturer, Centre for Systems Medicine
RCSI Physiology & Medical Physics Dept
Royal College of Surgeons in Ireland
Ireland

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: Liver cancer is the second most common cause of death from cancer worldwide, and the seventh most common cause of death from cancer in Europe (1).

“The incidence of liver cancers is increasing in developed countries, likely due to Western lifestyle and dietary habits. Liver cancers are often diagnosed at late stages and have limited treatment options,” says IARC scientist Dr Mazda Jenab, one of the study’s authors. “Further research is needed into the modifiable determinants of these cancers and effective prevention strategies.”

A growing body of evidence suggests that suboptimal intakes of the micronutrient selenium contribute to the development of several cancers (2). Selenium is a trace mineral micronutrient that is found in foods like shellfish, salmon, Brazil nuts, meat, eggs, grains, and onions. However, selenium levels in foods depend largely on the levels of selenium in the soil where the food is grown and animals graze. Soil levels tend to be low in many regions in Europe, contributing to lower body levels of selenium in those populations compared with people living in regions with higher soil selenium concentrations, such as North America. In humans, selenium is essential, particularly for the effective functioning of the immune system and in controlling oxidative processes linked to cancer development.

This new study shows that the highest levels of blood selenium or of selenoprotein P, the protein that distributes selenium from the liver around the body, are associated with a decreased risk of developing liver cancer (particularly hepatocellular carcinoma), even when all other major liver cancer risk factors are taken into account. The study also shows that selenium level is not associated with the development of gall bladder or biliary tract tumours (3).

The study was based on the European Prospective Investigation of Cancer and Nutrition (EPIC) cohort, headed by the International Agency for Research on Cancer (IARC) in Lyon, France,  and composed of more than half a million participants across 10 European countries. We used a case–control design of 121 liver cancers and 140 gall bladder and biliary tract cancers matched to equal numbers of individuals free of cancer within the cohort.

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