Selenium Supplements

Most in US Don't Need Selenium Supplements, Study Says

MyHealthNewsDaily Staff  CREDIT: Selenium photo via Shutterstock

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Selenium supplements may be harmful for people who already get enough of the mineral in their diets — which is most people in the U.S. — and could increase the risk for type 2 diabetes, according to a new review.

Use of selenium supplements has become widespread over the past 10 years, largely due to the belief that selenium can reduce the risk of cancer and other diseases. But "excessive zeal for increasing selenium intake has at times had adverse consequences," study author Margaret Rayman, a professor of nutritional medicine at the University of Surrey in England, wrote in her findings.

Those who get enough selenium in their diets should not take selenium supplements, Rayman concluded. People already get that mineral from grains, seafood and other common elements of the American diet.
The review will be published online Wednesday (Feb. 29) in the Lancet.

"Excessive zeal"

Though selenium supplements have been marketed for a multitude of conditions, this largely has been based on the results of observational studies, according to the paper. However, findings from clinical trials looking to confirm the supplements' effectiveness have been mixed.

Rayman reviewed selenium studies conducted since 1990. She said the mixed findings probably stem from the fact that supplements offer benefits only when the amount of selenium in a person's diet is inadequate.

Research has linked low selenium intake or levels in the blood with an increased risk of dying over a given period, poor immune function and cognitive decline. And higher selenium intake or blood levels have been linked to enhanced male fertility, antiviral effects, and protection against some cancers.

But the new review shows that levels that are too high can bring harmful effects.

Specifically, Rayman found people with high levels had an increased risk of type 2 diabetes. The link might be explained by the fact that selenium is incorporated into a protein, called GpX1, that affects the way insulin works in cells, she wrote.

Selenium in the diet

Selenium is a naturally occurring trace mineral found in soil and water and taken up by plants. The foods with the highest concentrations of selenium are organ meats and seafood, but the mineral is also found in cereals and grains, muscle meats and, to a lesser extent, dairy products, fruit and vegetables, according to the paper.

Recommendations for selenium intake average 60 micrograms per day for men, and 53 micrograms per day for women, according to the paper.

"The implications are clear: People whose serum or plasma selenium concentration is already 122 µg/L or higher — a large proportion of the U.S. population — should not supplement with selenium," Rayman wrote, pointing to data from blood samples taken as part of National Health and Nutrition Examination Survey, a large, ongoing study conducted by the Centers for Disease Control and Prevention.

Pass it on: Most Americans already get enough selenium from their diet, and supplements could raise their risk of diabetes.

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Internet Makes Us Smarter & Stupider!

Stephanie Pappas, LiveScience Senior Writer

What does a tech-savvy brain look like?
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Will constant access to the Internet make today's young people brilliant multitaskers or shallow, screen-bound hermits? A new opinion poll finds that technology experts believe the answer is "all of the above."

According to a new survey of 1,021 technology experts and critics, hyperconnectivity is a mixed bag. Fifty-five percent of those surveyed agreed that the Internet has wired the under-35 crowd differently, and that this rewiring is a good thing, stimulating multitasking talent and an ability to find relevant information fast online. But 42 percent of experts believe that the hyperconnected brain is shallow, with an unhealthy dependence on the Internet and mobile devices.

"Short attention spans resulting from quick interactions will be detrimental to focusing on the harder problems, and we will probably see a stagnation in many areas: technology, even social venues such as literature," Alvaro Retana, a technologist at HP, responded in the survey. "The people who will strive and lead the charge will be the ones able to disconnect themselves to focus."

Dire predictions

According to the Elon University Imagining the Internet Center and the Pew Internet Project, which conducted the survey, the technology expert split is closer to 50-50 on whether the rise of the Internet is a boon or a bane. Many people who responded that Internet-savvy Generation Y is at a mental advantage tempered that opinion with warnings about the dark side of connectedness. [10 Facts About the Teen Brain]

"While they said access to people and information is intensely improved in the mobile Internet age, they added that they are already witnessing deficiencies in younger people's abilities to focus their attention, be patient and think deeply," Janna Anderson, director of Elon's Imagining the Internet Center and a co-author of the report detailing the findings, said in a statement. "Some expressed concerns that trends are leading to a future in which most people are shallow consumers of information, and several mentioned Orwell's '1984.'"

George Orwell's 1949 book described a dystopian society where information was strictly controlled. One respondent who mentioned the book was Paul Gardner-Stephen, a telecommunications fellow at Flinders University.

"[C]entralized powers that can control access to the Internet will be able to significantly control future generations," Gardner-Stephen wrote. "It will be much as in Orwell's '1984', where control was achieved by using language to shape and limit thought, so future regimes may use control of access to the Internet to shape and limit thought."

Online optimism

Many experts praised the talents needed to navigate the Internet, however, and suggested that people who have grown up connected will blossom.

"There is no doubt that brains are being rewired," wrote danah boyd, a senior researcher at Microsoft Research. "The techniques and mechanisms to engage in rapid-fire attention shifting will be extremely useful for the creative class."

Other experts said that the use of the Internet as an "external brain" where facts are stored frees up space for mental processes beyond memorization. [Best Social Networking Sites Online]

"The replacement of memorization by analysis will be the biggest boon to society since the coming of mass literacy in the late 19th to early 20th century," wrote Paul Jones, a new media expert at the University of North Carolina, Chapel Hill.

While there was disagreement about the benefits and costs of an increasingly important Internet, experts were agreed that certain skills and talents would be important for future generations online. Among those were the ability to cooperate to solve problems, also known as crowd-sourcing; the ability to effectively search for information; the ability to synthesize information from many sources; the ability to concentrate; and the ability to filter useful information from the digital "noise" of the Internet.

"There is a palpable concern among these experts that new social and economic divisions will emerge as those who are motivated and well-schooled reap rewards that are not matched by those who fail to master new media and tech literacies," said report co-author Lee Rainie, director of the Pew Research Center's Internet & American Life Project. "They called for reinvention of public education to teach those skills and help learners avoid some of the obvious pitfalls of a hyperconnected lifestyle.”

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Can The Human Brain See Quantum Images?

Nobody knows whether humans can access exotic images based on quantum entanglement. Now one physicist has designed an experiment to find out

The strange rules of the quantum world lead to many weird phenomena. One of these is the puzzling process of quantum imaging, which allows images to form in hitherto unimagined ways.

Researchers begin by creating entangled pairs by sending a single laser  beam into a non-linear crystal, which converts single photons into entangled pairs of lower frequency photons, a process known as parametric down conversion. A continuous beam generates a series of pairs of entangled photons.

Next, they send the entangled photons towards a pair of detectors. Each member of an entangled pair by itself fluctuates in random ways that make its time and position of arrival uncertain.

Use one of the detectors to receive just one half of the entangled photons and the result is a blur, smeared by the process of randomness.

But use two detectors to receive both sets of photons and the uncertainties disappear, or at least are dramatically reduced. In this case, the 'image' is pinsharp. The uncertainty disappears because of the quantum correlation between the entangled pairs.

Researchers have extended this technique by superimposing a pattern on the wavefront of the initial laser beam, creating shapes such as a donut. They've shown that a single detector alone cannot 'see' a such a donut image even though it appears clean and sharp when two detectors pick up both sets of the entangled pairs.

These strange pictures are called quantum images or higher order images and quantum physicists think they can use them to carry out exotic processes such as sending information secretly and performing quantum lithography.

Today, Geraldo Barbosa at Northwestern University in Evanston, Illinois, raises another interesting possibility. He asks whether it is possible for humans to see higher order images and suggests that a relatively simple experiment could settle the question.

This experiment consists of a laser beam shaped into an image, such as the letter A. This laser then hits a non-linear crystal, generating entangled pairs of photons that retain this image shape. The set up is such that these photons are then detected, not by conventional detectors, but by human eyeballs.

The question is whether the human retina/brain combination can access the correlation that exists between the entangled pairs. If so, the human would see the letter A. If not, he or she would see only a blur.

Of course, there are some significant experimental challenges. One is to design the experiment in a way  that ensures the subject can only receive the image through this quantum process and not through some other channel, such as talking to the experimenter. However, that should be straightforward for any psychologist to design.

Another problem, however, is that the retina can only detect photons in groups of 7 or more and these have to arrive within a specific time window. Only then can a human subject 'see' the result. Generating the required intensity of entangled photons is one challenge.

The key question is whether the entanglement survives this group process. If the brain can access the quantum correlations, the image will be visible. If not, the result will be a blur.

That's a fascinating experiment not least because a positive result would be astounding. It would show that we humans can essentially 'see' entanglement.

Barbosa points out that new forms of imaging are not unknown in the animal world. Various animals and insects see in the infrared and ultraviolet, giving them an entirely different perspective on the world.

There is also some evidence that birds can 'see' the earth's magnetic field thanks to the quantum interaction between the field and light sensitive molecules in their retinas.

So the possibility that new ways of seeing the world can emerge is not unprecedented. However, the idea that humans can access higher order images thanks to quantum entanglement is clearly an idea of a different ilk.

Perhaps the most exciting aspect of Barbosa's idea is that it appears feasible now. There's no reason why this experiment couldn't be done in any quantum optics lab in the near future.

We'll look forward to seeing the results.

Ref: arxiv.org/abs/1202.5434: Can humans see beyond intensity images?

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