Saturday, November 06, 2010

Now vitamin E is in the poo

Another great icon of food faddism in trouble. Another black mark for "antioxidants" too. The effect described is quite small but great empires of faddism are built on such foundations

Doctors have warned against "indiscriminate" use of vitamin E supplements after a study found they increased the risk of a particularly serious type of stroke by more than a fifth. Analysis of almost 120,000 people, half given pure vitamin E supplements and half given placebos, found that they increased the risk of a haemorrhagic stroke by 22 per cent. The dose varied between 50mg and 500mg, compared to the EU RDA of 12mg.

Such strokes, where a blood vessel in the brain bursts, can have devastating effects and are sometimes fatal.

However, the study, published today (FRI) in the online version of the British Medical Journal, also found that taking vitamin E reduced the chances of an ischaemic stroke - where blood supply to a part of the brain is blocked - by 10 per cent. Ischaemic strokes tend not to have as severe consequences, although they can be fatal as well.

About one in five strokes are haemorrhagic and the remainder ischaemic.

However, the academics warned: "Given the relatively small risk reduction of ischaemic stroke and the generally more severe outcome of haemorrhagic stroke, indiscriminate widespread use of vitamin E should be cautioned against."

Millions of people take vitamin E supplements in Britain, either in pure form or contained in multivitamin pills. It is a powerful antioxidant that medics have suggested could help prevent cardiovascular disease by stopping fatty deposits building on artery walls.

The academics, led by Markus Sch├╝rks of Harvard Medical School, pointed out that the increased risk of haemorrhagic stroke was relatively small, with only one additional such incident likely for every 1,250 people taking vitamin E. They also said living a healthy lifestyle, reducing blood pressure and cholesterol levels had a far greater impact on reducing ischaemic stroke than taking vitamin E supplements.

Their analysis combined the results of nine individual trials, none of which had found vitamin E significantly altered the risk of stroke. However, they found that when put together the studies identified stark differences when looking at the effects on different types of stroke.

Around 8,500 people suffer bleed strokes every year in Britain, said Dr Peter Coleman, deputy director of research at The Stroke Association said. He said: "This is a very interesting study that shows that the risk of haemorrhagic stroke can be slightly increased by high levels of orally taken Vitamin E, although what is a ‘high level’ has not clearly been ascertained, and more research is required to discover the mechanism of action and the level at which Vitamin E can become harmful."

"The Stroke Association urges people to maintain a lifestyle of a balanced diet, regular exercise and monitoring their blood pressure to reduce their risk of a stroke but would be very interested in seeing further research into this study”.

Dr Carrie Ruxton, of the Health Supplements Information Service, saiid that overall study showed there were 0.6 fewer strokes per 1,000 people. "This suggests an overall benefit of vitamin E," she said. She also noted that the differences between the nine individual studies "hamper firm conclusions".


Zap of electricity makes you better at mathematics?

This is a very tiny study on a non-representative group so conclusions are premature. In my own research I have found high correlations among a small group of students fall away to nothing when a larger and more random sample is used

British-based researchers have found that passing a low current through a specific brain region can double your ability to do mathematics. They believe in future the technique may help people with dyscalculia, or "number blindness" – the mathematical equivalent of dyslexia.

But it is important to get the wiring right. If the electricity flows in the wrong direction it has the opposite effect, creating a person with a poor head for figures. The same team of Oxford University scientists previously showed that temporary dyscalculia could be induced with electrical brain stimulation.

In the new study, 15 student volunteers aged 20 and 21 were given a series of standard tests designed to assess numerical skills. The participants were timed to see how quickly and accurately they could solve mathematical puzzles involving symbols representing numerical values.

During the tests, a one milliamp current was passed across the parietal lobes of two groups of students, while a third group received a "fake" stimulus. The parietal lobe is a brain region that plays a crucial role in mathematical processing.

In one of the stimulated groups, the current flow was from the right to the left parietal lobe, while in the other the direction was reversed. Volunteers who received the right-left stimulus reached double the level of performance in the tests compared to the non-stimulated group after just a few sessions, the scientists reported in the journal Current Biology. In contrast, those stimulated with a left-right current saw their performance drop to about the same level as six-year-old children.

Students who received a fake "placebo" stimulus had results that fell half way between those of the other two groups.

Dr Cohen Kadosh, from Oxford University's Department of Experimental Psychology, who led the research, said: "We are not advising people to go around giving themselves electric shocks, but we are extremely excited by the potential of our findings and are now looking into the underlying brain changes.

"We've shown before that we can induce dyscalculia, and now it seems we might be able to make someone better at maths, so we really want to see if we can help people with dyscalculia, with a possible benefit to the general public. "Electrical stimulation is unlikely to turn you into the next Einstein, but if we're lucky it might be able to help some people cope better with maths."

The study is part of a large-scale project funded by the Wellcome Trust charity aimed at helping people with learning difficulties get better at maths.

One test, the Stroop test, creates counter-intuitive problems. Often it employs colours, where, for instance, the word red is written in green ink. Here, larger values were shown as smaller images and vice versa. Another task involved a mapping test where an image representing a value had to be correctly positioned between two others. In the same way, the number five is placed half way between a one and 9 on a line.

Commenting on the research, Dr Christopher Chambers, from the School of Psychology, University of Cardiff, said: "This is a really intriguing finding, showing that brain stimulation can boost numerosity skills, enhancing the ability to learn the link between arbitrary symbols and numbers, and then processing the symbols as though they actually are numbers. "The findings add to a growing body of research showing that certain types of brain stimulation, in certain contexts, can enhance brain function.

"One obvious implication for these findings lies in the development of methods for enhancing numerical skills in the general population, even for those who are not clinically impaired. Brain stimulation methods ... also have a lot of potential applications in promoting recovery following brain injury or developmental disorders."


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